To see the other types of publications on this topic, follow the link: Staphylococcal disease.
Dissertations / Theses on the topic 'Staphylococcal disease'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Staphylococcal disease.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Nutbeam-Tuffs, Stephen William. "Functional characterisation of superantigens in Staphylococcus aureus disease pathogenesis." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25519.
Full textAbstract:
Bacterial superantigens (SAgs) are virulence factors that induce nonspecific T-cell proliferation contributing to host immune avoidance, and occasionally severe life-threatening toxinoses such as toxic shock syndrome. In the current study, the multiple functions of 3 superantigens named staphylococcal enterotoxin-like toxins X, Y and Z are investigated. SElX and SElZ were non-emetic in a musk shrew model of emesis. SElX is structurally and phylogenetically related to staphylococcal superantigen-like proteins (SSls) which are non-mitogenic but exhibit a variety of immune modulatory properties. We carried out protein and gene expression analysis of mutants of different S. aureus gene regulators and demonstrated that selx expression is controlled by saeRS, a two-component regulator linked to the bacterial response to phagocytic signals. Considering the co-regulation of SElX with known mediators of innate immune evasion we investigated a potential role for SElX in both humoral and cellular innate immune modulation and discovered that SElX strongly binds to human, bovine, murine, and laprine neutrophils and interferes with IgG-mediated phagocytosis, independently of Fcγ receptor signalling. Bacterial survival assays with neutrophils demonstrated that the deletion of selx significantly reduced the ability of S. aureus to resist neutrophil killing. Site-directed mutagenesis in the conserved sialic acid-binding motif of SElX abolished its neutrophil binding capacity, which is consistent with a critical role for glycosylated receptors in this interaction. Importantly, the sialic-acid binding mutants of SElX retained the ability to induce T-cell proliferation demonstrating that the distinct functions of SElX are mechanistically independent. Affinity precipitation experiments identified potential glycoprotein receptors for SElX and the interaction with protein ICAM-3, an important ligand for MAC-1 integrins, was validated suggesting SElX may interfere with cell signalling. Taken together, we present the first example of a bi-functional SAg that can manipulate two distinct arms of the human immune system and contribute to S. aureus survival during infection.
2
Passalacqua, Edward F. "X-ray crystallographic studies of toxic shock syndrome toxin-1 and related superantigens." Thesis, University of Bath, 1995. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295442.
Full text
3
Lindberg, Hanna. "Engineering of Affibody molecules targeting the Alzheimer’s-related amyloid β peptide." Doctoral thesis, KTH, Proteinteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173864.
Full text
4
Röhrbein, Jan Hendrik [Verfasser]. "The influence of the staphylococcal Extracellular Adherence Protein on T cells functions in vitro in the context of the psoriasiform skin disease / Jan Hendrik Röhrbein." Ulm : Universität Ulm. Medizinische Fakultät, 2013. http://d-nb.info/1037395018/34.
Full text
5
Matar, Suzan. "Characterization of staphylococcal small colony variants and their pathogenic role in biomaterial-related infections with special reference to Staphylococcus epidermidis." Thesis, University of Nottingham, 2004. http://eprints.nottingham.ac.uk/12135/.
Full textAbstract:
There are many surgical implanted devices in current use and all are prone to biomaterial-related infections (BRI) associated with staphylococcal biofilm formation. BRI are usually associated with S. epidermidis or S. Aureus and are characterized by treatment failure and chronicity resulting in reoperation, removal of the implant, and loss of function or death. Staphylococcal small colony variants (SCVs) may be generated by exposure to sublethal concentrations of antibiotics or nutrient limitation which may occur in biofilms. Although the characteristics of S. aureus SCVs have been well studied, little information on SCVs of S. epidermidis and their potential role in BRI is currently available. This study was designed to investigate the biochemical and phenotypic characteristics of S. epidermidis SCVs to further identify characteristics which may contribute to their ability to cause these increasingly important infections. Exposure to two to four times the gentamicin MIC led to the emergence of stable S. epidermidis SCVs, and the ability to produce SCVs was strain dependent. These variants were isogenic by PFGE and less immunogenic by western blotting, and SDS-PAGE analysis of whole cell preparations and cell wall fractions showed altered protein profiles when compared to wild type strains. S epidermidis SCVs were resistant to aminoglycosides such as amikacin and/or netilmicin and they were thiamine and/or menadione auxotrophs. Chemiluminescence assays showed a decreased ATP content reflecting the deficiency in electron transport systems which results in a growth rate – all characteristics similar to those of S. aureus SCVs. Analysis of virulence factor production indicated that S. epidermidis SCVs showed increased lipolytic and proteolytic activity when compared to those of S. aureus. Some S. epidermidis SCVs showed phase variation in exopolysaccharide production which enabled them to be more adherent to uncoated plastic -a property that may also be important for the later stages of development of biofilms. Invasion assays demonstrated that some S. epidermidis and S. aureus SCVs were internalised by HUVECs by a receptor-mediated mechanism which differed from that of the wild type strains. Interaction of staphylococci with HUVECs induced cytokine production but SCVs stimulated production of IL1, IL-6 and IL-8 at lower concentrations than their related wild type parents in the first 6 hours of co-incubation. SCVs were also less damaging to the HUVEC cell line after 24 hours when compared to wild type strains. This study supports the suggestion that a switch to the S. epidermidis SCV phenotype could be a mechanism exploited by the wild type strains to facilitate their survival inside the host. The chronicity and increased antibiotic resistance associated with BRI could in part, be explained by the characteristics of SCVs identified in this study. In particular the ability to survive intracellularly combined with reduced immunogenicity and resulting decreased cytokine production, may contribute to persistence of infection. Although SCVs are resistant to some antibiotics, surviving intracellularly may further protect staphylococci from other drugs which are unable to enter mammalian cells. Resistance may be further enhanced for some strains in biofilms where enhanced polysaccharide production may also limit antibiotic access.
6
Ek, Moira. "Bacterial Display of a Tau-Binding Affibody Construct:Towards Affinity Maturation." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278580.
Full textAbstract:
Aggregation of microtubule-associated protein tau is involved in the pathology of several neurodegenerative diseases, including Alzheimer’s disease. The affibody TP4 has been shown to inhibit this aggregation process, and its target-binding positions were previously grafted onto a dimeric affibody scaffold, creating the sequestrin seqTP4. This project constitutes a part of the affinity maturation process of seqTP4, using two different bacterial display methods. An error-prone PCR library was first expressed on Staphylococcus carnosus cells for selection of variants with improved tau-binding properties, resulting in a library of 1.4×107 transformants. Flow cytometric tests indicated difficulties in the setup due to nonspecific interactions, and whereas several different approaches to alleviate the problems were investigated, two cell sorting attempts were ultimately unsuccessful. Subcloning of seqTP4 and the library to an Escherichia coli surface display vector resulted in functional surface expression of seqTP4 on E. coli JK321 and BL21 cells, and a BL21 library size of 1.6×109 transformants. An initial flow cytometric test of this library indicates the presence of improved tau-binding variants, paving the way for future cell sorting.Aggregering av mikrotubuli-associerat protein tau är involverad i patologin av flera neurodegenerativa sjukdomar, däribland Alzheimers sjukdom. Affibodymolekylen TP4 har visat sig inhibera denna aggregeringsprocess, och överföring av dess målbindande positioner till ett dimeriskt affibodyprotein har tidigare gett upphov till seqTP4, en så kallad sequestrin. Detta projekt utgör ett led i processen att affinitetsmaturera seqTP4, med hjälp av två olika metoder för presentation av proteiner på ytan av bakterieceller. Ett error-prone PCR-bibliotek uttrycktes först på ytan av Staphylococcus carnosus-celler för selektion av varianter med ökad affinitet för tau, vilket resulterade i ett bibliotek av 1.4×107 transformanter. Flödescytometriska tester tydde på svårigheter i detta upplägg på grund av ospecifika interaktioner, och emedan flera olika angreppssätt för att förmildra dessa problem undersöktes, misslyckades slutligen två cellsorteringsförsök. Omkloning av seqTP4 och biblioteket till en vektor för ytpresentation på Escherichia coli resulterade i funktionellt ytuttryck av seqTP4 på E. coli JK321- och BL21-celler, och ett BL21-bibliotek bestående av 1.6×109 transformanter. Ett första flödescytometriskt test av detta bibliotek tyder på närvaron av varianter med förbättrad förmåga att binda tau, och vägen ligger nu relativt öppen för cellsortering.
7
Lawal, Opeyemi U. "Evolutionary genomics of Staphylococcus saprophyticus: origin and disease signatures of pathogenic clones." Doctoral thesis, Universidade Nova de Lisboa, Instituto de Tecnologia Química e Biológica António Xavier, 2020. http://hdl.handle.net/10362/96280.
Full textAbstract:
"Staphylococcus saprophyticus is the second only to Escherichia coli as the leading cause of uncomplicated urinary tract infection (UTI), and it is associated with 10-20% of this type of infection in young women. Besides being a uropathogen, S. saprophyticus is also known to be a common coloniser of the gut, vagina, perineum, and the rectum of humans. Moreover, it colonises food producing animals such as pigs, and is a frequent contaminant of meat and fermented food products. Although the source(s) of S. saprophyticus causing UTI in humans are considered to be endogenous, increased contact with animal production settings and consumption of contaminated meat products have been hypothesised to increase the risk of human colonisation and infection with this bacterium.(...)"N/A
8
Brant, Jamet Ann. "Devleopment of an in vitro model of peritonitis complicating continuous ambulatory peritoneal dialysis." Thesis, University of Brighton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337400.
Full text
9
McGregor, Neil Roland. "An Investigation Of The Association Between Toxin-Producing Staphylococcus Biochemical Changes And Jaw Muscle Pain." University of Sydney, 1999. http://hdl.handle.net/2123/4697.
Full textAbstract:
Doctor of PhilosophyThis work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au
10
Thorberg, Britt-Marie. "Coagulase-negative staphylococci in bovine sub-clinical mastitis /." Uppsala : Dept. of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, 2008. http://epsilon.slu.se/10971614.pdf.
Full text
11
Wilson, Gillian Jane C. "Genome scale analysis of the role of superantigens in Staphylococcus aureus disease pathogenesis." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5706.
Full textAbstract:
Staphylococcus aureus produces a family of at least 21 distinct superantigens (SAgs) which include staphylococcal enterotoxins (SEs), staphylococcal enterotoxin-like toxins (SEls), and toxic shock syndrome toxin-1 (TSST-1), and contribute to disease pathogenesis via modulation of the host immune response. Specific SAgs have been shown to cause toxinoses such as staphylococcal food poisoning and toxic shock syndrome, and have been implicated in immunological disorders such as rheumatoid arthritis, psoriasis, and Kawasaki syndrome. However the role of SAgs in disease pathogenesis, in general, is poorly understood. S. aureus is a common cause of bovine mastitis. Analysis of the genome sequence of the bovine strain RF122 revealed genes encoding bovine variants of characterized SAgs, TSST-1, SElL, SEC, SEG, SEI, SElU, SElO, SElN and a truncated form of SElM. In addition we identified 3 genes with sequence homology to characterized SAgs, which are predicted to encode novel SAgs, SElX, SElY and SElZ. Expression of all 11 predicted SAg genes was detected in vitro, including several with growth phase-dependent expression. Characterization of a novel SAg, SElX which is encoded in the core genome of 94% of phylogenetically diverse S. aureus strains from human and animal infections was carried out. In addition to its superantigenic properties, SElX has a unique predicted structure characterized by a truncated SAg B domain. At least 14 different alleles of the selx gene were identified among the common human and animal pathogenic clones, and evidence for assortive recombination of selx alleles between distinct clonal lineages was discovered. SElX was expressed by representative human, bovine and ovine strains in vitro, in a growth phase dependent manner, and during human, bovine and ovine infections, consistent with a broad role in the pathogenesis of different S. aureus diseases in multiple hosts. SElX produced by bovine- and ovine-specialized S. aureus strains had 10-fold greater mitogenic activity and a distinct V activation profile for bovine lymphocytes compared to SElX made by the human strain USA300 indicating functional diversification of selx alleles from different hosts. This is the first description of a core-genome encoded SAg of S. aureus. The discovery that the great majority of S. aureus clinical isolates have superantigenic capacity has important implications for our understanding of staphylococcal disease pathogenesis. To investigate the role of SAgs in disease pathogenesis, a SAg-deficient strain of S. aureus, RF122-8 was constructed by sequential allele replacement. RF122-encoded SAg genes were cloned into the pALC2073 plasmid, which has an inducible promoter allowing controlled expression in the SAg-deficient strain RF122-8. These constructs allowed us to determine that TSST-1bov, SElLbov, SECbov, SElNbov, SEIbov and novel SAgs, SElXbov and SElYbov were mitogenic for bovine Tcells, and stimulated T-cell receptor variable (TRBV) sub-family-specific activation. Preliminary experimental intra-mammary infections of dairy cows revealed that clinical symptoms were similar during infection with wild type RF122 and SAg-deficient strains, including high somatic cell counts (6 LogSCC), and elevated body temperature (106 °F). However a higher infectious dose was required to establish infection with the SAg-deficient strain RF122-8 in comparison to the wild type, RF122 indicating an attenuation of virulence. Overall, these data provide broad new insights into the importance of SAgs in staphylococcal disease pathogenesis.
12
Jansen, van Vuuren Samuel Jacobus. "Identification of methicillin-resistant Staphylococcus aureus in horses using conventional and molecular techniques." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/57309.
Full textAbstract:
Staphylococcus aureus is a coagulase-positive, Gram-positive, coccal bacterium. It is one of the leading causes of both skin and invasive infections. It plays an important role in diagnostics and treatment due to its ability to develop resistance to antimicrobial drugs. Methicillin-resistant Staphylococcus aureus or MRSA is an important nosocomial pathogen in both humans and animals due to its resistance to all ?-lactam antimicrobial agents. Colonization of MRSA in horses poses a great concern. This is considered an important risk factor for development of staphylococcal related diseases in horses admitted to veterinary hospitals. Colonized horses can also be a source of zoonotic MRSA infections. Methicillin-resistant Staphylococcus aureus detection based on a PCR reaction is commonly used and various types of PCR-based assays were developed to assist in early detection of MRSA. The main aim of the study was to compare the currently used conventional microbiological techniques with a published multiplex PCR assay targeting the mecA, spa and pvl genes for the rapid and accurate identification of MRSA in horses admitted to the Onderstepoort Veterinary Teaching Hospital, University of Pretoria. A total of 50 isolates, which consists of isolates from horses and their immediate environment, were included in the study of which 94% (n=47) were shown to be infected with methicillin resistant Staphylococcus aureus using conventional microbiological techniques. The remaining three gave inconsistent results. Their isolates were obtained, DNA was extracted and subjected to the multiplex PCR assay. The PCR results indicated that both the mecA and spa genes were present in 72% (n=36) of these isolates, indicative of MRSA strains. In 20% (n=10) of the isolates, only the spa gene could be detected; suggesting that these cannot be classified as being methicillin resistant. The pvl gene could not be detected in any of the isolates tested. A total of four isolates (8%) yielded results that were inconsistent with being MRSA using molecular identification. Overall there was a good correlation between genotypic analysis by PCR and phenotypic determination using S. aureus species identification and susceptibility testing methods. The multiplex PCR assay had a detection limit of 2.18 x 108 colony-forming units (cfu)/ml. This detection limit is higher compared to other published molecular identification techniques used for Staphylococcus aureus but sensitive enough for the accurate detection of MRSA in overnight cultured isolates. Results suggest that the current PCR assay could be used as a supplementary diagnostic method in the routine diagnosis for rapid, sensitive, and specific detection of S. aureus and its associated antibiotic resistance genes in equine samples.Mini Dissertation (MSc)--University of Pretoria, 2015.
tm2016
Veterinary Tropical Diseases
MSc
Unrestricted
13
Stach, Christopher. "Characterizing the role of the enterotoxin gene cluster in Staphylococcus aureus diseases." Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/1909.
Full textAbstract:
Staphylococcus aureus is the leading cause of infective endocarditis in the United States. Infective endocarditis (IE) is defined as an infection of the endocardium, typically involving the heart valves. The hallmark features of IE are vegetations. Vegetations are cauliflower-like, stratified biofilms of bacteria and host factors that develop on the valve leaflets of the heart. The mechanisms of how vegetations form are not well understood, and as a consequence the bacterial factors that are important for development of IE are not well defined. My studies focus on the role of a family of S. aureus exoproteins known as superantigens and their role in IE.
Superantigens (SAgs) are a class of secreted virulence factors that have been extensively studied for their role in systemic diseases such as toxic shock syndrome (TSS), pneumonia, and food poisoning. The SAg protein family is comprised of 23 distinct members designated as staphylococcal enterotoxin (SE) or enterotoxin-like (SEl) and toxic shock syndrome toxin-1 (TSST-1). The term superantigen is derived from the ability of SAgs to interact with the immune system, resulting in a nearly 3000-fold increase in activation when compared to standard antigens. SAgs have a defined structure that is composed of 2 domains, a carboxy-terminal beta-grasp domain and amino-terminal oligosaccharide/oligonucleotide binding (OB) fold. Defined groups of SAgs are associated with S. aureus strains isolated from specific diseases, but few studies have been done to determine the role of SAgs in diseases outside of TSS and food poisoning.
The enterotoxin gene cluster (egc) is a group of 6 SAgs (selo, selm, sei, selu, seln, and seg) assembled into an operon-like cluster that is present in the majority of S. aureus strains isolated from IE patients. My studies have determined that the egc is able to induce vegetations when expressed in avirulent S. aureus strains. This is the first time the egc has been directly associated with IE. I further characterized the capacity of the individual egc proteins to induce vegetations. Four (selo, selm, sei, and selu) of the 6 egc SAgs were able to induce vegetation formation. This is the first time the individual egc proteins have been characterized and directly associated with IE. I also demonstrated that the egc proteins may not be exclusively expressed as a single polycistronic transcript but that selu and seg contain promoter elements that may drive their individual expression. Lastly, I provide evidence that the egc SAgs may be regulated by MgrA, a global regulator of S. aureus associated with virulence factor expression.
14
Moore, Catrin Elisabeth. "Case-control study of invasive Staphylococcus aureus disease-host genetic susceptibility and bacterial population structure." Thesis, University of Oxford, 2002. https://ora.ox.ac.uk/objects/uuid:85a3a6b4-b0cc-48ed-b584-5037ea884250.
Full textAbstract:
Staphylococcus aureus is a major pathogen associated with serious community-acquired and nosocomial disease. It is carried nasally at some time by 70% of the population, yet severe disease is relatively uncommon. Two case-control studies were conducted in Oxford, UK and Thailand to examine bacterial and host genetic determinants of severe S. aureus disease. Over 800 cases and 1,600 healthy control individuals were recruited into the two studies. The genetic population structures of S. aureus disease and carriage isolate populations from the Oxford study were studied and compared using phage typing, pulsed-field gel electrophoresis, and multilocus sequence typing. Natural populations of S. aureus have a well-defined clonal population structure, but there was no evidence for the existence of hypervirulent clones. The presence or absence of 33 putative bacterial virulence determinants was examined. After adjusting for the effect of clonality, seven determinants (fhbA, cna, sdrE, sej, eta, hlg and ica) were significantly more common in invasive isolates; all contributed independently to virulence. In the host genetic studies a functional single nucleotide polymorphism at amino acid position 131 of the Fc gamma receptor IIA (FcyRIIA) gene was significantly associated with severe disease. In addition an additive x additive epistatic interaction was found between this FcyRIIA polymorphism and the functional FcyRIIIB NA1/NA2 polymorphism. These significant associations were present when community-acquired disease cases were considered alone, but absent in hospital-acquired disease cases. The putatively functional polymorphisms in genes coding for mannose binding lectin and Tolllike receptor 2 were not associated with disease. Both bacterial and host factors are important in determining the occurrence of severe S. aureus disease. In hospital-acquired infection it is likely that acquired host, bacterial and environmental factors predominate, lessening the importance of any host genetic component.
15
Naidoo, Reené. "Epidemiology of Staphylococcus aureus bacteraemia at a tertiary children's hospital in Cape Town, South Africa." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/3064.
Full text
16
Walker, Jennifer B. "Towards a Better Understanding of the Epidemiology of Naturally Occurring Staphylococcus aureus Intramammary Infections." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1261596945.
Full text
17
Loeffler, Anette. "Epidemiological and genetic investigations of meticillin-resistant Staphylococcus aureus in companion animals." Thesis, Royal Veterinary College (University of London), 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558972.
Full textAbstract:
The hypotheses challenged in this project were (1) people are the source for meticillin-resistant Staphylococcus aureus (MRSA) in pets, (2) risk factors for MRSA infection and carriage mirror those described in humans, (3) S. aureus continues to evolve on animals, (4) MRSA is carried by a substantial number of companion animals and (5) pets can be a reservoir for MRSA. Risk factors for MRSA pet infection were determined in a UK-wide case-control study enrolling dogs and cats with S. aureus infection (138 MRSA; 122 MSSA), their veterinary staff and owners. MRSA were typed and 12 paired human-animal isolates were compared by whole genome microarrays. MRSA carriage was examined in selected populations of dogs, cats and horses (n=1692) in the Greater London area and dog-to-dog transmission of MRSA was examined during an outbreak in a rescue kennel. Key findings were (a) an occupational risk for MRSA carriage in UK first opinion veterinary staff (9%), (b) antimicrobial therapy, surgery and admission to veterinary hospitals as major risk factors for pet MRSA infection; (c) human healthcareassociated lineages predominated amongst animals but (d) host-specific variation occurred within the same lineage, (e) MRSA carriage in the studied animal populations was low «1.5%), (f) "classical" risk factors were not involved in animal carriage but co-carriage of other staphylococci was protective against MRSA, (g) decolonisation occurred naturally and (h) dog-to-dog transmission was not observed. MRSA ST398 was identified from one horse, the first isolation from an animal in the UK. These findings support the concept that pets acquire MRSA primarily from people but are unlikely natural hosts for healthcare-associated MRSA. Therefore, rigorous personal and environmental hygiene combined with conscientious use of antimicrobial agents should be highly effective in veterinary clinics. Bacterial interference should be further investigated as a preventative measure. Vigilance is warranted as new strains may evolve on and spread between companion animals.
18
Lindemann, Claudia. "Understanding early transcriptional events in Staphylococcus aureus infection." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:037d5fff-14f7-4587-baf1-39634ec8b9ab.
Full textAbstract:
Staphylococcus aureus remains an important pathogen, which, due to its capability to develop antimicrobial resistance, imposes an increasing threat to human health. Developing preventive means to decrease disease burden is a major aim. However, the development of an S. aureus vaccine, which would be one strategy to achieve such goals, has been complicated through limited understanding of the bacterium's pathogenic mechanisms. This work uses four approaches to address these limitations: Firstly, a reproducible RNA sequencing based method for the determination of gene transcription by S. aureus in vivo during mammalian infection. Secondly, examination of the impact of the bacterial transcription regulator 'Rsp' on the bacterium, which shows that mutations in this gene have profound functional and transcriptional impacts. Thirdly, by examining the in vivo transcription of multiple S. aureus strains during infection, proposing a 'core in vivo transcriptome' of induced genes under the conditions tested. Some of these genes are known to be involved in pathogenesis, others are not completely characterised and may represent suitable vaccine antigens. Finally, this work addresses limited understanding of S. aureus pathogenesis through defining transcriptional changes in vivo, which are induced by an altered immune response in immunised hosts. Together, this body of work contributes to the understanding of S. aureus pathogenesis and provides candidate antigens for future vaccine development.
19
Adegoke, Anthony Ayodeji. "Commensal bacteria belonging to the Staphylococcus Acinetobacter and Stenotrophomonas genera as reservoirs of antibiotic resistance determinants in the environment of Nkonkobe Municipality, Eastern Cape Province , South Africa." Thesis, University of Fort Hare, 2012. http://hdl.handle.net/10353/6539.
Full textAbstract:
A study to assess the potentials of some commensal bacteria that belong to Staphylococcus, Acinetobacter and Stenotrophomonas genera as reservoirs of antibiotic resistance determinants in the environment of Nkonkobe Municipality of the Eastern Cape Province, South Africa, was carried out using standard microbiological and molecular techniques. A total of 120 Staphylococcus isolates which consisted of Staphylococcus haemolyticus (30%), Staphylococcus aureus (23.3%) from pig; Staphylococcus capitis (15%) from goat; Staphylococcus heamolyticus (5%) and Staphylococcus xylosus (15%) from cattle and other Staphylococci (11%) from dead chicken and pigs were isolated. About 23.3% of these isolates were coagulase positive and 76.7% were coagulase negative. This difference in prevalence along coagulase production divide was statistically significant (p < 0.05). Eighty-six Acinetobacter species (Acinetobacter baumannii/calcoaceticus and Acinetobacter haemolyticus) were also isolated from Alice and Fort Beaufort towns samples, while 125 Stenotrophomonas maltophilia isolates were from grass root rhizosphere (96%) and soil butternut root rhizosphere (4%). Between 75-100% of the Staphylococccus species were resistant to Penicillin G, tetracycline, sulphamethaxole and nalidixic acid; about 38 % were methicillin resistant, consisting of 12.6% methicillin resistant Staphylococcus aureus (MRSA) from pig and a total of 12% vancomycin resistant were observed. Also, 12% of the isolates were erythromycin resistant while 40.2 % were resistant to the third generation cephalosporin, ceftazidime. The antibiotic resistance genes vanA, VanB, eryA, eryB, eryC were not detected in all the phenotypically resistant Staphylococccus species, but mec A gene and mph genes were detected. In the Acinetobacter species, a wide range of 30-100% resistance to penicillin G, ceftriazone, nitrofurantoin, erythromycin, and augmentin was observed. Polymerase chain reaction (PCR) revealed the presence of Tet(B) and Tet(39) genes in these species, while Tet (A), Tet(M) and Tet(H) were absent. Also, 9.3% of the Acinetobacter species showed phenotypic production of extended spectrum beta lactamases (ESBLs) while 3.5% were positive for the presence of blaCTX-M-1 genes. The Stenotrophomonas maltophilia isolates showed varying resistance to meropenem (8.9%), cefuroxime (95.6 %), ampicillin-sulbactam (53.9%), ceftazidime (10.7%), cefepime (29.3 %), minocycline (2.2%), kanamycin (56.9%), ofloxacin (2.9%), levofloxacin (1.3%), moxifloxacin (2.8%), ciprofloxacin (24.3%), gatifloxacin (1.3%), polymyxin B (2.9 %), cotrimoxazole (26.1%), trimethoprim (98.6%), aztreonam(58%) and Polymyxin B (2.9 %). The isolates exhibited significant susceptibility to the fluoroquinolones (74.3-94.7 %), polymycin (97.1%) and meropenem (88.1%). Only sul3 genes were the only sulphonamide resistance gene detected among the trimethoprim-sulphamethoxazole resistant isolates. The observed multiple antibiotic resistance indeces (MARI) of >2 for Staphylococcus species, Acinetobacter species and Stenotrophomonas maltophilia suggest that they have arisen from high-risk sources where antibiotics are in constant arbitrary use resulting in high selective pressure. The presence of tetracycline resistance genes in Acinetobacter species justifies the observed phenotypic resistance to oxytetracycline and intermediate resistance to minocycline. High phenotypic resistance and the presence of some resistance genes in Staphylococcus species is a possible threat to public health and suggests animals to be important reservoirs of antibiotic resistance determinants in the environment. Indiscriminate use of antibiotics induces this kind of antibiotic resistance and should be discouraged. Personal hygiene is encouraged as it reduces the load of Acinetobacter species contacted from the environment that may be difficult to control. Commensal Stenotrophomonas maltophilia are as important as their clinical counterparts due to their roles in opportunistic infection, antibiotic resistance and their associated genes, especially sul gene. Personal hygiene is hereby advocated especially when in contact with soil, plants and plants’ rhizospheric soil
20
Hård, af Segerstad Maja, and Elsa Larsson. "Riskfaktorer för spridning av MRSA på somatisk vårdavdelning : En litteraturstudie." Thesis, Uppsala universitet, Institutionen för folkhälso- och vårdvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325072.
Full textAbstract:
Bakgrund: Antibiotikaresistenta bakterier är idag ett stort hot mot folkhälsan. Det här arbetet fokuserar på MRSA och lyfter fram problematiken som dess spridning innebär för patienten, samhället och vårdpersonal. MRSA-bärarskap kan ge både fysiskt och psykiskt lidande och en infektion orsakad av MRSA kan i värsta fall leda till döden för patienten. Sjuksköterskan har en viktig roll i att upprätthålla sin kompetens och arbeta preventivt för att förhindra spridning av MRSA. Syfte: Syftet var att identifiera och beskriva faktorer som leder till spridning av MRSA vid vårdarbetet av patienter på somatisk vårdavdelning. Metod: En litteraturstudie där 11 kvantitativa och en kvalitativ artikel analyserades utifrån Graneheim och Lundmans (2004) metod för innehållsanalys. Artiklarna kvalitetsgranskades med hjälp av Forsberg och Wengströms (2016) granskningsmallar. Resultat: Resultatet delades in i fem huvudkategorier med nio underkategorier som var och en visar på kompetensbrist hos sjuksköterskor. Litteraturstudien påvisar att faktorerna som leder till spridning av MRSA kan vara flera och att hela vårdteamet bär ett ansvar för att förhindra smittspridning. Sjuksköterskans roll i vårdteamet är att undervisa patienter och närstående, följa gällande rutiner och att upprätthålla sin egen kompetens för att arbeta evidensbaserat. Slutsats: Förhindra spridning av antibiotikaresistenta bakterier är en av sjuksköterskans viktigaste arbetsuppgifter i sin roll att lindra lidande hos patienten. Det är många faktorer som kan göra att MRSA sprids, sjuksköterskor måste reflektera och vara självkritiska i sitt arbete på vårdavdelningar. Evidensbaserat arbete var enligt Nightingale sjuksköterskans möjlighet att förhindra lidande för patienten och ligger till grund för den sjuksköterskeutbildning som finns idag.Background: Antibiotic resistant bacteria are today a major threat to the public health. This work focuses on methicillin resistant staphylococcus aureus, highlighting the problem that it involves for the patient, society and healthcare professionals. MRSA carriership can cause both physical and mental suffering and an infection caused by MRSA can in worst case lead to the patient’s death. Nurses play an important role in maintaining their work skills to prevent MRSA from spreading in the somatic care. Aim: The aim of this study was to identify and describe factors that lead to the spread of MRSA to patients in somatic care. Method: A literature study where 11 quantitative and one qualitative article were analyzed based on Graneheim and Lundman's (2004) method. The articles quality were reviewed using Forsberg and Wengström’s (2016) checklists. Results: The results were divided into five main categories with nine subcategories; each showing that nurses had a lack of competence. The study shows that the factors that lead to the spread of MRSA may be several, and that the entire healthcare team has a responsibility to prevent infection. The nurse's role in the team is to teach patients and close relatives, follow current procedures and maintain their own skills to work evidence based. Conclusion: Preventing the spread of antibiotic resistant bacteria is one of the most important tasks in role of nursing and in alleviating patient suffering. There are many factors that can cause MRSA to spread. Nurses must reflect and be self-critical in their work in health care departments. Evidence based work was, according to Nightingale, the nurse's ability to prevent suffering for the patient and is the baseline in nursing education currently available today.
21
Rodgers, J. D. "An investigation into Staphylococcus aureus associated with chicken disease : characterisation, control measures and interactions with the chicken immune system." Thesis, Queen's University Belfast, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396897.
Full text
22
Bacca, Juan David Valencia. "Pesquisa de genes codificadores de adesinas em Staphylococcus spp. isolados de amostras clínicas em cães e gatos." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/10/10134/tde-28082015-124850/.
Full textAbstract:
Os Staphylococcus spp., são bactérias Gram positivas com importância clinica, as quais são capazes de causar uma ampla variedade de doenças em seres humanos e animais. O uso excessivo de antimicrobianos pode selecionar bactérias resistentes aos antimicrobianos de uso comum em Veterinária, o que representa uma grande ameaça para a saúde animal, e a saúde publica no mundo inteiro. Apesar de sua importância clinica, existe um conhecimento limitado sobre a patogênese das infecções estafilococicas em animais de estimação, e os fatores de virulência bacterianos específicos envolvidos em estas doenças. A Infecção estafilocócica iniciasse a partir da adesão do micro-organismo ao tecido do hospedeiro. A adesão é favorecida pela presença de fatores de virulência conhecidos como adesinas, que estão agrupadas em uma família conhecidas como as microbial surface components recognising adhesive matrix molecules (MSCRAMM). Após o isolamento e identificação dos micro-organismos, 118 estirpes de Staphylococcus spp., foram identificadas, 111 (94.07%), estirpes em cães, e 7 (5.93%) em gatos. Entre os Staphylococcus, sete espécies diferentes foram isoladas: 82 (69.49%) Staphylococcus pseudointermedius, 19 (16.10%) Staphylococcus epidermidis, 7 (5.93%) Staphylococcus xylosus, 4 (3.39%) Staphylococcus chromogenes, 3 (2.54%) Staphylococcus spp., 2 (1.69%) Staphylococcus aureus, 1 (0.85%) Staphylococcus schleiferi. A susceptibilidade a 26 agentes antimicrobianos foi determinada em todos os isolados. A pesquisa pelas MSCRAMM e o gene formador de biofilme nas estirpes de Staphylococcus spp., foi realizada usando a reação em cadeia da polimerasa (PCR), foram usados diferentes pares de primers para detectar os genes que codificam para a proteína ligadora de colágeno (cna), proteína ligadora de laminina (eno), proteína ligadora de elastina (ebpS), proteína ligadora de fibrinogênio (fib), proteína A ligadora de fibronectina (FnbA), proteína B ligadora de fibronectina (FnbB), e proteína associada a formação de biofilme (Bap). A resistência apresentada pelas estirpes isoladas aos diversos antimicrobianos foi observada com frequência, a percentagem de resistência geral das cepas de Staphylococcus spp isoladas foi: 54,32% para eritromicina, 40,79% para clindamicina, e 29,91% para norfloxacina. A susceptibilidade a oxacilina tambem foi testada, o 85,96% das estirpes isoladas foram susceptíveis. Todos os genes foram identificados com exceção do Bap e EbpS, o gene mais frequentemente isolado foi o Eno (89,9%), a associação entre os genes Eno/Fib/FnbA e Eno/FnbB foram também detectadas. Nossos resultados evidenciaram que os membros do gênero Staphylococcus apresentam frequentemente resistência in vitro aos antimicrobianos usados comumente. É necessário fazer um uso criterioso de antibióticos em animais de estimação em Medicina Veterinária. A informação sobre o assunto pode permitir o desenvolvimento de estratégias mais eficazes para o tratamento e controle das infeções causadas por Staphylococcus spp., em pequenos animaisStaphylococcus spp., are clinically important Gram-positive bacteria that are capable of causing a wide variety of diseases in humans and animals. The overuse of antimicrobials can select resistant bacteria strains, that represents a major threat to animal and public health worldwide. Despite its clinical importance, there is only very limited knowledge about the pathogenesis of staphylococcal infections in small animals, and the specific bacterial virulence factors involved in causing these diseases. Staphylococcal infection initiates from the adhesion of the microorganism to the tissue of the host. Adhesion is favoured by the presence of virulence factors known as adhesins, which are grouped in a family known as the microbial surface components recognising adhesive matrix molecules (MSCRAMM). After isolation and identification of microorganisms, 118 Staphylococcus strains were identified, 111 (94.07%) strains from canine and 7 (5.93%) from feline origin. Among Staphylococcus, seven different species were isolated: 82 (69.49%) Staphylococcus pseudointermedius, 19 (16.10%) Staphylococcus epidermidis, 7 (5.93%) Staphylococcus xylosus, 4 (3.39%) Staphylococcus chromogenes, 3 (2.54%) Staphylococcus spp., 2 (1.69%) Staphylococcus aureus, 1 (0.85%) Staphylococcus schleiferi. The susceptibility to 26 antimicrobials was determined in all the isolates. The search for MSCRAMM and biofilm-encoding genes in the strains of Staphylococcus spp. was performed using a polymerase chain reaction (PCR). Primers were used to detect the genes encoding for collagen-binding protein (cna), laminin-binding protein (eno), elastin-binding protein (ebpS), fibrinogen-binding protein (fib), fibronectin-binding protein A (fnbA) and fibronectin-binding protein B (fnbB) and biofilm formation-encoding genes (bap). Resistance of isolates to antibiotics was frequently observed, the percentage of resistance in the general Staphylococcus strains was: 54,32% to erythromycin, 40,79% to clindamycin, and 29,91% to norfloxacin. Susceptibility to oxacilin was also tested, 85,96%) % of the isolates were susceptible. All genes were detected except for ebpS and bap. The most frequently detected gene in both species was eno (89, 9%). Association of genes Eno/Fib/FnbA and Eno/FnbB were also detected. Our results highligthed that members of the Staphylococcus genus often exhibit in vitro resistance to commonly used antimicrobials. Its necessary a judicious use of antibiotics in small animals Veterinary Medicine. Such information on the subject allows the development of more efficient strategies for treatment and control of Staphylococcus infection in small animals
23
Masson, Guido Carlos Iselda Hermans [UNESP]. "Staphylococcus aureus na cadeia produtiva de suínos e perfil de resistência a antimicrobianos." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/101216.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:31:10Z (GMT). No. of bitstreams: 0
Previous issue date: 2011-12-16Bitstream added on 2014-06-13T20:01:47Z : No. of bitstreams: 1
masson_gcih_dr_jabo.pdf: 739097 bytes, checksum: 2fef2cb4d684c81bde182928eafa28f3 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
S. aureus é responsabilizado por diversos problemas clínicos em suinocultura e em humanos. Estudos epidemiológicos comprovam o potencial deste microrganismo em adquirir resistência a antibióticos. Atualmente estirpes resistentes a meticilina (MRSA), responsabilizados por casos de infecções nosocomiais, são as mais estudadas uma vez que o MRSA encontra-se disseminado em ambientes extra-hospitalares e frenquentemente tem sido isolado de vários animais domésticos inclusive suínos. O objetivo desde trabalho foi determinar a presença de S. aureus em granjas de suínos, identificar a ocorrência dos genes mecA, icaA e icaD e o perfil de resistência a antimicrobianos. Ao todo foram colhidas 458 amostras de cinco granjas e dois frigoríficos. As amostras foram semeadas em ágar Braid - Parker e ágar sangue seguido de provas bioquímicas. As amostras sugestivas, foram submetidas a PCR para confirmação de espécie, detecção do gene coa, mecA para avaliar a resistência a meticilina além dos genes de virulência icaA e icaD que expressam capacidade para formação de biofilmes. Na sequência, realizou-se o antibiograma para a avaliação de 11 antimicrobianos. Ao todo foram identificados 81 (79%) S. aureus isolados de todas as granjas e frigoríficos incluindo, três amostras isoladas de funcionários das granjas. Nenhuma amostra foi positiva para o gene mecA. Em relação aos genes icaA e icaD, observou predomínio do gene icaD e que 41% das amostras foram positivas para os dois genes. O antibiograma demonstrou grande resistência às penicilinas e tetraciclinas, além de grande quantidade de S aureus multirresistentes
Staphylococcus aureus are involved in a wide range of clinical problems to swine industry as son in humans. Epidemiological researchs prove his potential to acquire resistantence to antibiotics. Nowadays, methicillin-resistant S. aureus (MRSA) are responsabilized for nosocomial infections and many studies are done because MRSA are spread to extra hospitalar enrivonment and frequentely isolated from domestic animals including pigs. The aim of this study was to determine the presence o S. aureus at swine farms and identify the mecA, icaA and icaD genes and the resistant proflife to antibiotics. Overal, 458 swabs were taked from five pigeris and two slautherhouses. All the samples were placed on Braid – Parker and blood agar follow by biochemical analyses. The suspect colonies were submitted to PCR to confirm the S. aureus species, by the detection of the coa gene, mecA to avaible meticillin-resistant as son to the virulence gens icaA and icaD that can determine slime production. Antibiogram were done to evaluate the response to 11 antibiotics. All pigeris and slautherhouse were positive and 81 (79%) samples were S. aureus positive including three isolates from pigs employeers. The mecA gene was not detected. The icaD gene was most frequent and 41% were positive to both genes. The antibiogram show a lot of samples penicillin and tetraciclin resistant. Most of the samples were multirestant
24
Blunt, Catherine Ann. "Antimicrobial susceptibility profiles of Staphylococcus intermedius isolates from clinical cases of canine pyoderma in South Africa." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/24953.
Full textAbstract:
Successful treatment of canine pyoderma has become increasingly difficult due to the development of antimicrobial resistance and recurrence of infection. The development and spread of antimicrobial resistance has major implications because treatment failures have been associated with increased mortality, morbidity and costs related to disease. All canine skin samples submitted to Vetdiagnostix Veterinary Pathology Services for microbiological culture and sensitivity between January 2007 and June 2010, from which Staphylococcus intermedius was isolated, were selected for this investigation. A total of 319 samples from dogs of various ages, sexes and breeds from various locations throughout South Africa were obtained. In addition to the antimicrobial susceptibility data, data relating to dog signalment (age, gender, breed), case history and any other aspects of the history provided e.g. diagnosis, sample type and geographical location of the patient were collected. The number of skin samples yielding Staphylococcus intermedius was high in dogs up to the age of 6 years and, then decreased with only a few cases in dogs aged 11 years or older. The distribution of samples collected in 2010 was unusual in that there were two peaks, one in dogs two years old or less and one in 6 to 9-year-old dogs. With the exception of skin samples taken in 2008, a high percentage of dogs were under the age of one year old. 2008 had a lower percentage of affected dogs less than one year of age compared to the other years. Staphylococcal pyoderma is more common in dogs below the age of five years. Dogs above this age are less likely to contract this condition. The genders tended to be equally distributed throughout the years, with almost equal proportions of affected males and females present. The Bull Terrier types and Shepherd types were grouped separately as they were over-represented and are known to be prone to pyoderma. Large short haired dogs were consistently worse affected throughout the years sampled, followed by the Bull Terrier types. In 2010, small short haired breeds were worse affected compared to the numbers between 2007 and 2009. The monthly distribution, with the exception of 2009, tended to be consistent throughout the years. The unusual temporal distribution in 2009 could be associated with a general distribution in the number of samples compared to the other years sampled. Samples tended to be mainly from practices located in the KwaZulu-Natal province of South Africa. This is most likely due to the fact that the laboratory is located in this province, with a courier network that arranges collection from these practices. Practices in other regions send their samples to the laboratory via private courier companies and the South African Post Office. Antimicrobial resistance of S. intermedius was greatest to ampicillin followed by tetracycline and then potentiated sulphonamides. The results also showed that, in general, antimicrobial resistance was low. Very few methicillin resistant isolates were detected. Temporal trends were not noted, with the exception of ampicillin where isolates became more susceptible and potentiated sulphonamides (co-trimoxazole) where isolates were becoming more resistant. Staphylococcus intermedius is significantly less resistant to erythromycin, clindamycin, cephalexin, oxacillin, amoxicillin-clavulanic acid, enrofloxacin, marbofloxacin and gentamicin, with most strains being susceptible to these drugs. Resistance to penicillin and tetracycline is frequently found in Staphylococcus intermedius and is on the increase. Resistance to most other antimicrobials, particularly newer generation antimicrobial agents such as the fluoroquinolones, is still comparatively low. In general, both the Kirby-Bauer and broth dilution MIC tests yielded similar results for the antimicrobial agents tested. The main difference between the two tests was evident in the over-estimation of resistance by the Kirby-Bauer test in the cases of ampicillin, co-trimoxazole, penicillin and doxycycline. This could be related to the instability of these particular drugs in vitro. Inoculum densities may also have played a role, with denser inocula producing smaller zone sizes for the drugs tested. Using the MIC method, all of the isolates tested were found to be completely sensitive to ticarcillin, oxacillin, amoxicillinclavulanic acid, imipenem, ceftiofur, chloramphenicol, doxycycline, gentamicin, amikacin and co-trimoxazole. Of the isolates tested using the MIC method, between 2-40% showed some level of resistance to the following antimicrobials: erythromycin, penicillin, ampicillin, enrofloxacin, clindamycin and marbofloxacin. The highest level of resistance observed was shown to erythromycin. The increase in resistance to the lincosamides, lincomycin, clindamycin and erythromycin may be attributed to the increased use of these drugs in the last decade. Knowledge of trends in bacterial resistance is important for veterinarians when determining treatment for canine skin infections. The information obtained from the analysis of the antimicrobial susceptibility profiles of Staphylococcus intermedius isolated from canine pyoderma cases will provide veterinarians with valuable information on choosing the most appropriate drug to treat S. intermedius skin infections as well as re-enforcing the need for the prudent use of antimicrobial drugs in companion animals. CopyrightDissertation (MSc)--University of Pretoria, 2011.
Veterinary Tropical Diseases
unrestricted
25
Masson, Guido Carlos Iselda Hermans. "Staphylococcus aureus na cadeia produtiva de suínos e perfil de resistência a antimicrobianos /." Jaboticabal : [s.n.], 2011. http://hdl.handle.net/11449/101216.
Full textAbstract:
Orientador: Luiz Fernando de Oliveira e Silva CarvalhoBanca: Everlon Cid Rigobelo
Banca: Aníbal de Sant'Anna Moretti
Banca: Luiz Carlos Marques
Banca: Mario Roberto Hatayde
Resumo: S. aureus é responsabilizado por diversos problemas clínicos em suinocultura e em humanos. Estudos epidemiológicos comprovam o potencial deste microrganismo em adquirir resistência a antibióticos. Atualmente estirpes resistentes a meticilina (MRSA), responsabilizados por casos de infecções nosocomiais, são as mais estudadas uma vez que o MRSA encontra-se disseminado em ambientes extra-hospitalares e frenquentemente tem sido isolado de vários animais domésticos inclusive suínos. O objetivo desde trabalho foi determinar a presença de S. aureus em granjas de suínos, identificar a ocorrência dos genes mecA, icaA e icaD e o perfil de resistência a antimicrobianos. Ao todo foram colhidas 458 amostras de cinco granjas e dois frigoríficos. As amostras foram semeadas em ágar Braid - Parker e ágar sangue seguido de provas bioquímicas. As amostras sugestivas, foram submetidas a PCR para confirmação de espécie, detecção do gene coa, mecA para avaliar a resistência a meticilina além dos genes de virulência icaA e icaD que expressam capacidade para formação de biofilmes. Na sequência, realizou-se o antibiograma para a avaliação de 11 antimicrobianos. Ao todo foram identificados 81 (79%) S. aureus isolados de todas as granjas e frigoríficos incluindo, três amostras isoladas de funcionários das granjas. Nenhuma amostra foi positiva para o gene mecA. Em relação aos genes icaA e icaD, observou predomínio do gene icaD e que 41% das amostras foram positivas para os dois genes. O antibiograma demonstrou grande resistência às penicilinas e tetraciclinas, além de grande quantidade de S aureus multirresistentes
Abstract: Staphylococcus aureus are involved in a wide range of clinical problems to swine industry as son in humans. Epidemiological researchs prove his potential to acquire resistantence to antibiotics. Nowadays, methicillin-resistant S. aureus (MRSA) are responsabilized for nosocomial infections and many studies are done because MRSA are spread to extra hospitalar enrivonment and frequentely isolated from domestic animals including pigs. The aim of this study was to determine the presence o S. aureus at swine farms and identify the mecA, icaA and icaD genes and the resistant proflife to antibiotics. Overal, 458 swabs were taked from five pigeris and two slautherhouses. All the samples were placed on Braid - Parker and blood agar follow by biochemical analyses. The suspect colonies were submitted to PCR to confirm the S. aureus species, by the detection of the coa gene, mecA to avaible meticillin-resistant as son to the virulence gens icaA and icaD that can determine slime production. Antibiogram were done to evaluate the response to 11 antibiotics. All pigeris and slautherhouse were positive and 81 (79%) samples were S. aureus positive including three isolates from pigs employeers. The mecA gene was not detected. The icaD gene was most frequent and 41% were positive to both genes. The antibiogram show a lot of samples penicillin and tetraciclin resistant. Most of the samples were multirestant
Doutor
26
Nickerson, Emma Katherine Francoise. "Defining the burden of morbidity and mortality due to invasive staphylococcus aureus disease and the Impact of drug resistance in Thailand." Thesis, Open University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522297.
Full text
27
Gibbons, Cheryl Leanne. "Epidemiology of MRSA in Scotland." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20447.
Full textAbstract:
Staphylococcus aureus (S. aureus) is a bacterium that commonly colonises the skin and nares of around one third of otherwise healthy individuals. While colonisation is benign, S. aureus can cross skin and mucosal barriers to cause infections that manifest as clinical disease. Clinical outcomes are diverse and range from mild, non-complicated and often self-limiting skin and soft tissue infections (including boils, abscesses and cellulitis) to more severe and life-threatening conditions including pneumonia, toxic shock syndrome and bacteraemia. Medication isn’t always needed for mild S. aureus infections as often they resolve with time but, for severe or persistent cases, antimicrobial treatment is generally required. Following decades of widespread and intensive usage of topical, enteral and parenteral antimicrobials to treat S. aureus infections; AMR has become an established and ubiquitous problem in the treatment of infections caused by this microorganism, especially when in the methicillin resistant form (i.e. MRSA). The aim of this thesis was to examine aspects of S. aureus epidemiology (including MRSA and methicillin-sensitive S. aureus (MSSA)) in Scotland using statistical methods and data from several large public health databases. More specifically this involved: descriptions of spatial and temporal trends of morbidity and mortality; comparisons of epidemiological and molecular attributes (including antimicrobial resistance) of (1) MSSA and MRSA, and (2) the dominant clones of MRSA (i.e. EMRSA-15 and EMRSA-16); descriptions of spatial and temporal trends of antimicrobial prescribing in primary and secondary care and any associations between prescribing rates and MRSA antimicrobial resistance; and carrying out a hospital-level risk factor analysis of MRSA, testing hypotheses that hospital size, hospital connectivity (through shared transfer patients) and hospital category have an effect on hospital-level incidences of MRSA in mainland Scottish hospitals. Results showed that total S .aureus bacteraemia and MRSA bacteraemia in Scotland statistically declined over time (p < 0.0001), but MSSA bacteraemia did not (p > 0.05). While combined mortality rates (i.e. all MSSA deaths (both primary and secondary cause), or all MRSA deaths (both primary and secondary cause)) mirror these findings; case-fatality ratios (CFR) show no declines over time for either MRSA or MSSA. Results also show that several epidemiological factors point towards a predominant community source for MSSA isolates (i.e. outside healthcare) and hospital source for MRSA. Evidence for this included: (1) the lack of resistance genes in the MSSA population, (2) MRSA was more associated with long-term care and high-risk patients in the specialties care of the elderly, high dependency units/intensive care units (HDU/ICU), and surgery and conversely MSSA with specialties that commonly served outpatients, and (3) the abundance of non-EMRSA-15/non- EMRSA-16 ‘other’ clones in the MSSA population as compared with the hospital-associated CC22 (EMRSA-15) and CC30 (EMRSA-16) clones. EMRSA-15 was by far the most dominant MRSA clone in Scotland with EMRSA-16 declining significantly and non-EMRSA-15/non-EMRSA-16 clones causing an increasing number of infections (over the time period 2003-2013). EMRSA-16 was resistant to a larger number of antimicrobials than EMRSA-15, typically 9 versus 5, and while resistance varied for EMRSA-16 over the study period, resistance remained stable for EMRSA-15. There was little difference between clinical and screening MRSA isolates. Analyses of antimicrobial prescribing showed that prescribing rates of several drugs increased over time (2003-2013). Prescribing was far higher in primary care settings than in secondary care, although this differed between antimicrobials. Significant positive associations between prescribing and resistance rates were found for gentamicin (pr - p<0.0001, se - p<0.0001) and trimethoprim (pr - p<0.01, se - p<0.0001) in both primary (pr) and secondary (se) care, and clindamycin (p<0.0001) in primary care only. Finally, in Scotland there is a threshold of connectivity above which the majority of hospitals, regardless of size, are positive for MRSA. Higher levels of MRSA are associated with the large, highly connected teaching hospitals with high ratios of patients to domestic staff. While there were a number of data limitations, this body of work provides a better understanding of the epidemiology of S. aureus including MRSA in Scotland.
28
Silva, Ana Paula da. "Suscetibilidade antimicrobiana de Staphylococcus spp. isolados de cães com pioderma superficial." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/10179.
Full textAbstract:
Superficial pyoderma is the bacterial infection of the epidermis and hair follicle
and is a common skin disease in dogs. The main etiological agents involved are bacteria
of the Staphylococcus genus. This skin disease represents one of the main indications
for antimicrobial therapy by small animal practitioners, a procedure usually performed
empirically. The emergence of multidrug-resistant staphylococci species in skin
infections has been reported in many countries and implies difficulties in the treatment.
This study aimed to determine the antimicrobial susceptibility and evaluate the presence
of multidrug resistance in 154 isolates of Staphylococcus spp. from skin lesions of dogs
with superficial pyoderma that were assisted by the Veterinary Dermatology Service at
the Hospital Veterinário Universitário (HVU) of the Universidade Federal de Santa
Maria (UFSM). After bacterial culture and identification, the isolates were tested for
antimicrobial susceptibility, and the results showed high rates of resistance to
amoxicillin (60.4%) and penicillin G (60.4%), moderate resistance to potentiated
sulfonamides (29.9%), enrofloxacin (20.1%), ciprofloxacin (18.8%) and azithromycin
(17.5%), and low percentages of resistance to the amoxicillin and clavulanic acid
association (1.9%), cephalexin (1.9 %), cefadroxil (1.9%) and vancomycin (0.6%). The
multidrug resistance was detected in 23.4% (11/154) and the methicillin resistance in
5.8% (9/154) of the samples. It may be concluded that the Staphylococcus spp. isolates
present high susceptibility to key antimicrobials used in the treatment of superficial
pyodermas in dogs at the HVU-UFSM, such as cephalexin and the amoxicillin and
clavulanic acid association, confirming the preference for these drugs when treating
dogs with this disorder. The susceptibility of the isolates to fluoroquinolones, also
recommended in the literature as an alternative in the treatment of pyodermas, allows
suggesting that such drugs should not be considered in the empirical selection. The
identification of multidrug-resistant Staphylococcus spp. in the studied canine
population justifies periodic and regional bacteriological tests of skin lesions in dogs
with superficial pyoderma, to minimize bacterial resistance, possible therapeutic failures
and also motivates wise use of antimicrobial therapy.Pioderma superficial é a infecção bacteriana da epiderme e folículo piloso e é considerada uma das doenças de pele mais frequentes em cães. Os principais agentes etiológicos envolvidos são bactérias do gênero Staphylococcus. Essa dermatopatia representa uma das principais indicações de antimicrobianoterapia pelos clínicos de pequenos animais, procedimento habitualmente realizado de forma empírica. A emergência de espécies estafilococos multirresistentes em infecções cutâneas tem sido relatada em diversos países e implica em dificuldades no tratamento. Este estudo teve como objetivo determinar a suscetibilidade antimicrobiana e avaliar a presença de multirresistência em 154 isolados de Staphylococcus spp. oriundos de lesões cutâneas de cães com pioderma superficial atendidos no Serviço de Dermatologia Veterinária do Hospital Veterinário Universitário (HVU) da Universidade Federal de Santa Maria (UFSM). Após cultura e identificação bacteriana, os isolados foram submetidos ao teste de sensibilidade aos antimicrobianos, cujos resultados evidenciaram elevados percentuais de resistência frente à amoxicilina (60,4%) e penicilina G (60,4%), moderada resistência às sulfonamidas potencializadas (29,9%), enrofloxacina (20,1%), ciprofloxacina (18,8%) e azitromicina (17,5%) e baixos percentuais de resistência à associação amoxicilina e ácido clavulânico (1,9%), cefalexina (1,9%), cefadroxil (1,9%) e vancomicina (0,6%). A multirresistência foi detectada em 23,4% e a resistência à meticilina em 5,8% das amostras. Pode-se concluir que os isolados de Staphylococcus spp. apresentam elevada suscetibilidade aos antimicrobianos comumente utilizados no tratamento dos piodermas superficiais em cães no HVU-UFSM, como a cefalexina e a amoxicilina associada ao ácido clavulânico, confirmando a eleição desses fármacos para o tratamento de cães com esta afecção. A suscetibilidade dos isolados frente às fluoroquinolonas, também recomendadas pela literatura como opção terapêutica nos piodermas, permite sugerir que esses fármacos não devem ser considerados na seleção empírica. A identificação de Staphylococcus spp. multirresistentes na população canina estudada justifica análises bacteriológicas periódicas e regionais de lesões cutâneas de cães com pioderma superficial, a fim de minimizar resistência bacteriana, possíveis falhas terapêuticas e também motiva a antimicrobianoterapia prudente.
29
Roy, Mélanie. "Identification and characterization of differentially expressed genes in response to Escherichia coli and Staphylococcus aureus in bovine mammary epithelial cells and mammary gland." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98785.
Full textAbstract:
Bovine mammary glands respond to infection by foreign pathogens such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) through changes in gene expression. Monitoring the gene expression profiles will contribute to better understanding of the pathology of mastitis, and provide important selective markers for future animal breeding programs. Using cultured bovine mammary duct epithelial cells and somatic cells from infected bovine mammary glands, this study first examined the existence of Toll Like Receptors in these two systems. In cultured duct epithelial cells stimulated with E. coli LPS, both TLR 4 and 2 mRNA up regulation was detected at 2h-72h and 12h-48h respectively. For S. aureus LTA TLR 2 mRNA was up regulated at 48 and 72h whereas for TLR 4 mRNA expression up regulation was detected at 24, 48, and 72h in comparison to the Oh (p<0.05). In the case of PGN, an abundant structural component of S. aureus, the expression of TLR 2 mRNA was significant (p<0.05) at 72h whereas TLR 4 mRNA expression increased at 24, 48, and 72h. The expression of these receptors was also monitored in milk cells from cows infected with either E. coli or S. aureus. However, results obtained from the milk cells were inconclusive due to the high individual variability. Afterwards, differential gene expression profiles were monitored by the Differential Display Polymerase Chain Reaction technique in the cultured duct epithelial cells in response to E. coli and S. aureus structural components. A total of 6 candidate fragments were identified for E. coli LPS induction, whereas only one fragment was identified for S. aureus LTA induction. After LTA induction, a specific band was found to be up regulated and confirmed to be GCP-2, a chemokine involved in neutrophil recruitment. In contrast, PGN induction resulted in no change in GCP-2 levels. In different preparations of cultured duct epithelial cells both GCP-2 and IL-8 were confirmed by real time PCR to be up regulated by LTA with a significance of (p<0.01) when compared to the control cells. In the case of the E. coli identified bands, a different approach is necessary to potentially confirm the origin of these fragments. Further large scale screening of the GCP-2 and IL-8 genes in dairy cattle is necessary to test for their potential use as targets to differentiate the mastitis resistant from the mastitis prone cows.
30
Thompson, James Russell. "Imaging the assembly of the Staphylococcal pore-forming toxin alpha-Hemolysin." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:e320004a-6118-4dac-af2a-eca6e90be7ac.
Full textAbstract:
Alpha-hemolysin is a pore-forming toxin secreted by pathogenic Staphylococcus aureus. Its spontaneous oligomerization and assembly into a trans-bilayer beta-barrel pore is a model for the assembly of many other pore-forming toxins. It is studied here in vitro as a means to probe general membrane protein oligomerization and lipid bilayer insertion. This thesis details the results of experiments to develop and implement a novel in vitro lipid bilayer system, Droplet-on-Hydrogel Bilayers (DHBs) for the single-molecule imaging of alpha-hemolysin assembly. Chapter 2 describes the development of DHBs and their electrical characterization. Experiments show the detection of membrane channels in SDS-PAGE gels post-electrophoresis and DHBs use as a platform for nanopore stochastic sensing. Chapter 3 describes the engineering and characterization of fluorescently-labelled monomeric alpha-hemolysin for use in protein assembly imaging experiments described in Chapter 6. Chapter 4 describes the characterization of DHB lipid fluidity and suitability for single-molecule studies of membrane protein diffusion. In addition, a novel single-particle tracking algorithm is described. Chapter 5 describes experiments demonstrating simultaneous electrical and fluorescence measurements of alpha-hemolysin pores embedded within DHBs. The first multiple-pore stochastic sensing in a single-lipid bilayer is also described. Chapter 6 describes experiments studying the assembly of alpha-hemolysin monomers in DHBs. Results show that alpha-hemolysin assembles rapidly into its oligomeric state, with no detection of long-lived intermediate states.
31
Demircioğlu, Doğan Doruk [Verfasser], and Friedrich [Akademischer Betreuer] Götz. "Investigations on immune sensing of Staphylococcus aureus in allergic and inflammatory bowel diseases / Doğan Doruk Demircioğlu ; Betreuer: Friedrich Götz." Tübingen : Universitätsbibliothek Tübingen, 2015. http://d-nb.info/119705748X/34.
Full text
32
Fontoura, Eduardo Garcia. "Rosmarinus officinalis L. e Triticum aestivum no tratamento da otite externa infecciosa." Universidade Federal de Pelotas, 2014. http://repositorio.ufpel.edu.br/handle/ri/2511.
Full textAbstract:
Made available in DSpace on 2014-08-20T14:37:54Z (GMT). No. of bitstreams: 1
dissertacao_eduardo_garcia_fontoura.pdf: 1413088 bytes, checksum: 273e6ae790ff7b3245afb5b091828f85 (MD5)
Previous issue date: 2014-02-14External otitis is an inflammation of the outer ear and ear canal, which may or may not be of infectious cause. Negligence will lead to recurrence, hampering treatment and causing bacterial resistance to conventional methodologies. In this context, medicinal plants and plant extracts may be an alternative. Triticum aestivum (wheat) has been shown to act as an antioxidant, anti-inflammatory, pain-killer, as well as used in wound healing. Rosmarinus officinalis L. (rosemary) has antibacterial, anti-inflammatory, pain-killer, anti-mutagenic, diuretic, expectorant, and antioxidant effects. In this context, the objective of this study was to assess the use of wheat and rosemary aqueous extracts, and rosemary essential oil, in the treatment of infectious external otitis. Experimental otitis was induced in rats Wistar with croton oil at 5% in acetone, followed by the introduction of Staphylococcus aureus in the outer ear canal. Animals were separated according to the treatment group: GI 25% wheat aqueous extract in propylene glycol; GII 25% rosemary aqueous extract in propylene glycol; GIII 5% rosemary essential oil in propylene glycol; GIV propylene glycol; and GV saline. The animals were treated for up to seven days, and assessed regarding clinical (according to the Emgard & Hellström method) and hitopathological alterations, on days four, six and ten. Promising results were observed on animals treated with both aqueous extracts, primarily in GI (wheat), but also in GII (rosemary), both were able to reduce clinical and histopathological parameters beyond the effect of the control. This study shows that the aqueous extract of both T. aestivum and R. oficinallis promoted the hastening of the healing process of infectious external otitis.
A otite externa é a inflamação do conduto auditivo externo, com etiologia infecciosa ou não. Casos de negligência fazem com que ocorram recidivas, dificultando tratamento e elevando a resistência microbiana aos métodos convencionais, tornando assim as plantas medicinais uma alternativa. O Triticum aestivum (trigo), já demonstrou ação antioxidante, anti-inflamatório, antimicrobiano, hepatoprotetor e cicatrizante. O Rosmarinus officinalis L. (alecrim) possui propriedades medicinais como antimicrobiano, anti-inflamatório, analgésico, antimutagênico, diurético, expectorante e antioxidante. Neste contexto, objetivou-se avaliar a utilização dos extratos aquosos de trigo e alecrim e óleo essencial de alecrim no tratamento da otite externa infecciosa experimental. A otite externa foi induzida em 64 ratos Wistar através da instilação de óleo de cróton 5% em acetona em conjunto com Staphylococcus aureus no conduto auditivo dos animais. Os tratamentos foram divididos em extrato aquoso de trigo 25% em propilenoglicol (GI), extrato aquoso de alecrim 25% em propilenoglicol (GII), óleo essencial de alecrim 5% em propilenoglicol (GIII), propilenoglicol (GIV) e solução fisiológica (GV). Os animais foram tratados por até sete dias e realizadas análises macroscópicas aos quatro, seis e dez dias através do método de Emgård & Hellström para coloração, diâmetro, efusão, além da análise histopatológica, em quatro animais por grupo. Foram observados resultados promissores com o extrato aquoso de trigo (GI), e extrato aquoso de alecrim (GII), sendo capazes de reduzir os parâmetros clínicos macroscópicos, assim como os parâmetros histopatológicos. Nas condições experimentais deste trabalho, a concentração utilizada de óleo essencial não foi efetiva. Assim, demonstrou-se que os extratos aquosos de trigo e alecrim a 25% em propilenoglicol promovem a aceleração da resolução da otite externa infecciosa.
33
Jariwala, Nidhi H. "Characterization of Staphylococcal nuclease and tudor domain containing protein 1 (SND1) as a molecular target in Hepatocellular carcinoma and Non-alcoholic steatohepatitis." VCU Scholars Compass, 2017. https://scholarscompass.vcu.edu/etd/5183.
Full textAbstract:
CHARACTERIZATION OF STAPHYLOCOCCAL NUCLEASE AND TUDOR DOMAIN CONTAINING PROTEIN 1 (SND1) AS A MOLECULAR TARGET IN HEPATOCELLULAR CARCINOMA AND NON-ALCOHOLIC STEATOHEPATITIS
Nidhi Jariwala, PhD
A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Integrative Life Sciences
Virginia Commonwealth University, 2017
Devanand Sarkar, M.B.B.S., PhD.
Associate Professor, Department of Human and Molecular Genetics
Virginia Commonwealth University
Richmond, Virginia
SND1, a subunit of the miRNA regulatory complex RISC, has been implicated as an oncogene in hepatocellular carcinoma (HCC). Oncoprotein SND1 regulates gene expression at a post-transcriptional level in multiple cancers including hepatocellular carcinoma (HCC). In the present study, we characterize oncogenic functions of SND1 in HCC employing a novel transgenic mouse model (Alb/SND1) and present SND1 as a potential molecular target in HCC management. We show that Alb/SND1 mice develop spontaneous HCC with partial penetrance and exhibit more highly aggressive HCC induced by chemical carcinogenesis. Livers from Alb/SND1 mice exhibit a relative increase in inflammatory markers and spheroid-generating tumor initiating cells (TiC). Mechanistic investigations defined roles for Akt and NF-κB signaling pathways in promoting TiC formation in Alb/SND1 mice. Intravenous administration of the selective SND1 inhibitor 3', 5'-deoxythymidine bisphosphate (pdTp) inhibited tumor formation without effects on body weight or liver function. We conclude that SND1 drives pro-oncogenic transcriptomic and proteomic changes in hepatocyte resulting in aggressive HCC. SND1 specific RNA interactome is identified with RNA immunoprecipitation sequencing (RIPSeq) approach. With an adjusted p value of2-fold enrichment over control, 282 mRNAs were identified to significantly associate with SND1 protein. We focused on the tumor suppressor Protein Tyrosine Phosphatase non-receptor type 23 (PTPN23) because its regulation by SND1 and its role in HCC are not known. In current study, we confirm that SND1 post-transcriptionally downregulates PTPN23. Pursuing functional studies with tetracycline inducible overexpression system, we validate that PTPN23 inhibits tyrosine kinase signaling, proliferation, epithelial to mesenchymal transition, migration, invasion and in vivo tumorigenesis.
Alb/SND1 mice also manifest steatosis and fibrosis at one year of age. Coupled with a pro-inflammatory hepatic phenotype, we conclude that Alb/SND1 livers present NASH. High fat diet causes severe NASH and aggressive NASH induced HCC in Alb/SND1 mice. Serum and hepatic lipid profiling shows that hepatocyte specific SND1 overexpression associate with elevated triglyceride and cholesterol LDL levels. Contrarily, hepatocyte specific deletion of SND1 (SND1ΔHEP) in vivo, significantly protects against age dependent steatosis. Association of SND1 in NASH pathology is novel discovery and we present preliminary evidence confirming role of SND1 in promoting NASH.
34
Silva, Nathália Cristina Cirone [UNESP]. "Caracterização molecular de Staphylococcus sp, isolados de leite de vacas com mastite, em diferenes regiões do estado de São Paulo." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/100593.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:30:57Z (GMT). No. of bitstreams: 0
Previous issue date: 2013-06-07Bitstream added on 2014-06-13T19:40:32Z : No. of bitstreams: 1
silva_ncc_dr_botib.pdf: 675325 bytes, checksum: 770804101b6bf91187e2941b56d767bb (MD5)Staphylococcus sp é agente comum da mastite bovina, causando grandes perdas econômicas na pecuária brasileira. Esse micro-organismo possui fatores de virulência bastante conhecidos como a produção de hemolisinas, leucotoxinas e superantígenos como a toxina do síndrome do choque tóxico e enterotoxinas. Além disso, várias espécies de Staphylococcus podem adquirir genes de resistência aos antibióticos β lactâmicos. O objetivo do estudo foi caracterizar molecularmente isolados de Staphylococcus sp provenientes de leite de vacas com mastite clinica e subclínica de várias regiões do estado de São Paulo. Foram realizadas coletas de leite de vacas com mastite clinica e subclínica de diferentes fazendas no estado de São Paulo e realizados testes fenótipicos de resistência a antimicrobianos e de virulência (Toxina de Panton Valentine, sindrome do choque tóxico e toxinas esfoliativas), além de testes moleculares como Pulse Field Gel Eletrophoresis (PFGE), Multiloccus Sequence Typing (MLST) e Spa typing para comparação entre as cepas epidemiologicamente importantes e da tipagem do cromossomo cassette estafilocócico em cepas meticilina reistentes. As cepas resistentes a meticilina apresentaram amplo perfil de resistência e genes de resistência importantes e pouco relatados, sendo observados genes como fexA, lsaE, lnuB. Foram detectados dois novos spatyping (t10852 e t10856), bem como um novo alelo yqiL e um novo ST (2493). Os ECNs apresentaram resistências à maioria dos antibióticos estudados e foi observado a uma deleção no gene ermC, que codifica a resistência à eritromicina.
Staphylococcus sp. is the common agent of bovine mastitis, causing big economic losses in Brazilian cattle. This micro-organism have virulence factors have been well known as the production of hemolysin, and leucotoxinas toxin superantigens such as toxic shock syndrome and enterotoxins. In addition, several Staphylococcus species can acquire antibiotic resistance genes β lactamics. The objective of the study is to characterize molecularly Staphylococcus sp. from milk of cows with subclinical mastitis in various regions of the state of São Paulo. Samples were coleted from milk of cows with subclinical and clinical mastitis from different farms in the state of São Paulo. Tests were performed phenotypic antimicrobial resistance and virulence (toxin Panton Valentine, toxic shock syndrome and exfoliative toxins), molecular tests as Eletrophoresis Pulse Field Gel Electrophoresis (PFGE), Multiloccus Sequence Typing (MLST) and spa typing for comparison between epidemiologically important strains, as well as the typing of strains in staphylococcal cassette chromosome methicillin reistentes. Methicillin-resistant strains showed broad resistance profile and resistance genes important and underreported were detected as fexA, lsaE, lnuB. Two new spatyping (t10852 and t10856) were detected as well as a new allele yqiL and a new ST (2493). The ECN showed resistance to most antibiotics and was observed the deletion in ermC gene encoding resistance to erythromycin.
35
Silva, Nathália Cristina Cirone. "Caracterização molecular de Staphylococcus sp, isolados de leite de vacas com mastite, em diferenes regiões do estado de São Paulo /." Botucatu, 2013. http://hdl.handle.net/11449/100593.
Full textAbstract:
Orientador: Vera Lucia Mores RallCoorientador: João Pessoa Araujo junior
Banca: Ary Fernandes Junior
Banca: Carlos Henrique Camargo
Banca: José Paes de Almeida Nogueira
Banca: Lina Casale Aragon-Alegro
Resumo: Staphylococcus sp é agente comum da mastite bovina, causando grandes perdas econômicas na pecuária brasileira. Esse micro-organismo possui fatores de virulência bastante conhecidos como a produção de hemolisinas, leucotoxinas e superantígenos como a toxina do síndrome do choque tóxico e enterotoxinas. Além disso, várias espécies de Staphylococcus podem adquirir genes de resistência aos antibióticos β lactâmicos. O objetivo do estudo foi caracterizar molecularmente isolados de Staphylococcus sp provenientes de leite de vacas com mastite clinica e subclínica de várias regiões do estado de São Paulo. Foram realizadas coletas de leite de vacas com mastite clinica e subclínica de diferentes fazendas no estado de São Paulo e realizados testes fenótipicos de resistência a antimicrobianos e de virulência (Toxina de Panton Valentine, sindrome do choque tóxico e toxinas esfoliativas), além de testes moleculares como Pulse Field Gel Eletrophoresis (PFGE), Multiloccus Sequence Typing (MLST) e Spa typing para comparação entre as cepas epidemiologicamente importantes e da tipagem do cromossomo cassette estafilocócico em cepas meticilina reistentes. As cepas resistentes a meticilina apresentaram amplo perfil de resistência e genes de resistência importantes e pouco relatados, sendo observados genes como fexA, lsaE, lnuB. Foram detectados dois novos spatyping (t10852 e t10856), bem como um novo alelo yqiL e um novo ST (2493). Os ECNs apresentaram resistências à maioria dos antibióticos estudados e foi observado a uma deleção no gene ermC, que codifica a resistência à eritromicina.
Abstract: Staphylococcus sp. is the common agent of bovine mastitis, causing big economic losses in Brazilian cattle. This micro-organism have virulence factors have been well known as the production of hemolysin, and leucotoxinas toxin superantigens such as toxic shock syndrome and enterotoxins. In addition, several Staphylococcus species can acquire antibiotic resistance genes β lactamics. The objective of the study is to characterize molecularly Staphylococcus sp. from milk of cows with subclinical mastitis in various regions of the state of São Paulo. Samples were coleted from milk of cows with subclinical and clinical mastitis from different farms in the state of São Paulo. Tests were performed phenotypic antimicrobial resistance and virulence (toxin Panton Valentine, toxic shock syndrome and exfoliative toxins), molecular tests as Eletrophoresis Pulse Field Gel Electrophoresis (PFGE), Multiloccus Sequence Typing (MLST) and spa typing for comparison between epidemiologically important strains, as well as the typing of strains in staphylococcal cassette chromosome methicillin reistentes. Methicillin-resistant strains showed broad resistance profile and resistance genes important and underreported were detected as fexA, lsaE, lnuB. Two new spatyping (t10852 and t10856) were detected as well as a new allele yqiL and a new ST (2493). The ECN showed resistance to most antibiotics and was observed the deletion in ermC gene encoding resistance to erythromycin.
Doutor
36
Loberto, Jussara Cia Sanches. "Staphylococcus spp. Na cavidade bucal e na bolsa periodontal de indivíduos com periodontite crônica : presença e sensibilidade aos antibióticos /." São José dos Campos, 2002. http://hdl.handle.net/11449/110737.
Full textAbstract:
Orientador: Antonio Olavo Cardoso JorgeBanca: Antonio Olavo cardoso Jorge
Banca: Elizabete Brasil dos Santos
Banca: José Roberto Cortelli
Banca: Rocha, Rosilene Fernandes da
RESUMO: Staphylococcus não são usualmente estudados na cavidade bucal. Quando presentes são considerados pertencentes à microbiota transitória. Indivíduos que apresentam doença periodontal representam possíveis reservatórios dessas bactérias oportunistas na cavidade bucal. O uso de antibióticos, quer seja para tratamento da doença periodontal, ou em consequência de infecções hospitalares, pode predispor o aumento do número de Staphylococcusspp. naboca, pois estes adquirem facilmente resistência aos antibióticos, podendo resultar em super-infecção. Participaram deste estudo 88 pacientes, com no mínimo 25 anos de idade e apresentando periodontite crônica, com pelo menos dois sítios com profundidade de sondagem maior ou igual a 5mm. Após anamnese e exame clínico periodontal foram feitas coletas de material da bolsa periodontal com cones de papel e da cavidade bucal por meio de bochechos. Do total de pacientes 37,50% apresentaram Staphylocaccusspp. na bolsa periodontal e 61,36% na cavidade bucal, sendo que 27,27% apresentaram a bactéria nos 2 sítios, não sendo necessariamente a mesma espécie. S. epidermidisfoi a espécie mais prevalente para bolsa periodontal (15,9%) e cavidade bucal (27,27%). Foram positivos para S. aureus na bolsa periodontal, 4,5% e para cavidade bucal 25%, sendo 3,4% positivos para os dois sítios. Não houve diferença estatística significante quanto à presença desses microrganismos entre as faixas etárias, hábito de fumar e aumento da profundidade de sondagem. A maioria das cepas de Staphylococcus isoladas mostrou resistência aos antibióticos testados, indicando que a utilização sistêmica destas drogas, como adjunto à terapia periodontal. deve ser vista com cautela
ABSTRACT: "Staphylococcus" are not usually studied in the oral cavity, when this happens, they are considered to belong to transitory microflora. Individuals that present periodontal disease represent possibles reservoirs of these opportunist bacteria in the oral cavity. The use of antibiotics whether for treatment of periodontal disease or due to hospital infections, may predispose the increase of the "Staphylococcus" spp. in the oral cavity because they easily become resistant to antibiotics, resulting in superinfection. The study was made with 88 patients, minimum age- 25 years old, presenting chronical periodontitis, with, at least, two sites having a probing pocket bigger or equal to 5mm. After anamnese and clinical periodontal examination samples were taken from the periodontal pocket using paper cones and from the oral cavity using mouth rinse. Of the total patients 37,50% presented "Staphylococcus" spp. in the periodontal pocket and 61,36% in lhe oral cavity; 27,27% presented bacteria in the two sites, not necessarily of the same specie. "S. epidermidis" was the most prevailing specie in periodontal pocket (15,9%) and oral cavity (27,27%). Positive for "S. aureus" in the periodontal pocket were 4,5% and for the oral cavity 25%, and 3,4% were positive for the two sites. There was not found significative statistical difference referring to the presence of the microorganisms as to age, smoking habit and increase of the probing depth. The majority of the isolated "Staphylococcus" samples showed resistance to the tested antibiotics, indicating that the drugs as an adjunct to periodontal therapy, must be seen with caution
Doutor
37
Loberto, Jussara Cia Sanches [UNESP]. "Staphylococcus spp. Na cavidade bucal e na bolsa periodontal de indivíduos com periodontite crônica: presença e sensibilidade aos antibióticos." Universidade Estadual Paulista (UNESP), 2002. http://hdl.handle.net/11449/110737.
Full textAbstract:
Made available in DSpace on 2014-11-10T11:10:01Z (GMT). No. of bitstreams: 0
Previous issue date: 2002-05-06Bitstream added on 2014-11-10T11:57:21Z : No. of bitstreams: 1
000164631.pdf: 2914434 bytes, checksum: 63a362e437b9653b359c2844495da99f (MD5)Staphylococcus não são usualmente estudados na cavidade bucal. Quando presentes são considerados pertencentes à microbiota transitória. Indivíduos que apresentam doença periodontal representam possíveis reservatórios dessas bactérias oportunistas na cavidade bucal. O uso de antibióticos, quer seja para tratamento da doença periodontal, ou em consequência de infecções hospitalares, pode predispor o aumento do número de Staphylococcusspp. naboca, pois estes adquirem facilmente resistência aos antibióticos, podendo resultar em super-infecção. Participaram deste estudo 88 pacientes, com no mínimo 25 anos de idade e apresentando periodontite crônica, com pelo menos dois sítios com profundidade de sondagem maior ou igual a 5mm. Após anamnese e exame clínico periodontal foram feitas coletas de material da bolsa periodontal com cones de papel e da cavidade bucal por meio de bochechos. Do total de pacientes 37,50% apresentaram Staphylocaccusspp. na bolsa periodontal e 61,36% na cavidade bucal, sendo que 27,27% apresentaram a bactéria nos 2 sítios, não sendo necessariamente a mesma espécie. S. epidermidisfoi a espécie mais prevalente para bolsa periodontal (15,9%) e cavidade bucal (27,27%). Foram positivos para S. aureus na bolsa periodontal, 4,5% e para cavidade bucal 25%, sendo 3,4% positivos para os dois sítios. Não houve diferença estatística significante quanto à presença desses microrganismos entre as faixas etárias, hábito de fumar e aumento da profundidade de sondagem. A maioria das cepas de Staphylococcus isoladas mostrou resistência aos antibióticos testados, indicando que a utilização sistêmica destas drogas, como adjunto à terapia periodontal. deve ser vista com cautela
Staphylococcus are not usually studied in the oral cavity, when this happens, they are considered to belong to transitory microflora. Individuals that present periodontal disease represent possibles reservoirs of these opportunist bacteria in the oral cavity. The use of antibiotics whether for treatment of periodontal disease or due to hospital infections, may predispose the increase of the Staphylococcus spp. in the oral cavity because they easily become resistant to antibiotics, resulting in superinfection. The study was made with 88 patients, minimum age- 25 years old, presenting chronical periodontitis, with, at least, two sites having a probing pocket bigger or equal to 5mm. After anamnese and clinical periodontal examination samples were taken from the periodontal pocket using paper cones and from the oral cavity using mouth rinse. Of the total patients 37,50% presented Staphylococcus spp. in the periodontal pocket and 61,36% in lhe oral cavity; 27,27% presented bacteria in the two sites, not necessarily of the same specie. S. epidermidis was the most prevailing specie in periodontal pocket (15,9%) and oral cavity (27,27%). Positive for S. aureus in the periodontal pocket were 4,5% and for the oral cavity 25%, and 3,4% were positive for the two sites. There was not found significative statistical difference referring to the presence of the microorganisms as to age, smoking habit and increase of the probing depth. The majority of the isolated Staphylococcus samples showed resistance to the tested antibiotics, indicating that the drugs as an adjunct to periodontal therapy, must be seen with caution
38
Oliveira, Larissa Marques de. "Detecção e caracterização molecular de Staphylococcus aureus meticilina resistente em amostras de pacientes hepatopatas." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5134/tde-11052015-133426/.
Full textAbstract:
Introdução: Staphylococcus aureus é um patógeno que frequentemente coloniza pacientes cirróticos e transplantados de fígado. A colonização por S. aureus aumenta o risco de infecções invasivas por MRSA (Methicillin Resistant Staphylococcus aureus) o que aumenta a duração da hospitalização, os custos, a morbidade e a mortalidade. Com isso, é de grande importância o desenvolvimento de estratégias para identificação rápida, prevenção e controle de MRSA nesta população de pacientes. Objetivos: detectar MRSA em pacientes hepatopatas e descrever as características fenotípicas e moleculares de isolados MRSA neste grupo de pacientes. Metodologia: swabs nasais e inguinais foram coletados de 126 pacientes pré-transplante e 64 pacientes transplantados de fígado. Os swabs foram destinados para cultura microbiológica e também para extração direta de DNA. Foi determinada a Concentração Inibitória Mínima de 10 antimicrobianos de todos os isolados MRSA os quais também foram submetidos à caracterização de SCCmec, PFGE e spa typing. Amostras de DNA também foram submetidas à PCR 16S, MPCR coA/mecA e caracterização de SCCmec. Resultados: de acordo com a cultura microbiológica 12% dos swabs cultivados apresentaram crescimento de MRSA, resultando em 44 isolados MRSA. Todos os isolados foram resistentes à oxacilina, penicilina e sensíveis à vancomicina; todos amplificaram os genes coA e mecA; SCCmec tipo II e spa t002 predominaram nos dois grupos de estudo; além disso houve um cluster entre os isolados, o qual foi relacionado ao clone New York/Japan. O Clone Endêmico Brasileiro (BEC) foi relacionado somente à 4 isolados póstransplante. 98% das amostras de DNA amplificaram o gene 16S; a M-PCR identificou a presença de MRSA em 71% amostras de DNA e 61% das amostras tiveram a caracterização de SCCmec. O SCCmec tipo II predominou nos dois grupos de estudo. Conclusão: uma alta proporção de pacientes hepatopatas está colonizada com MRSA. Pacientes transplantados de fígado foram mais colonizados que pacientes cirróticos pela cultura microbiológica. A M-PCR coA/mecA diretamente de swabs foi mais sensível que a cultura microbiológica para identificar MRSA. Além disso, o PFGE demonstrou ter maior poder discriminatório que spa typing e não houve uma boa concordância entre os padrões de PFGE e spa types. Este estudo também demonstrou que está havendo uma mudança de clones MRSA em nosso hospital, devido à substituição do clone BEC pelo clone NY/Japan na última décadaIntroduction: Staphylococcus aureus is a pathogen that frequently colonizes cirrhotic and also liver transplanted patients. The S. aureus colonization increases the risk of invasive infections by MRSA (Methicillin Resistant Staphylococcus aureus) that increases the duration of hospitalization, costs, morbidity and mortality. Thus, it is of great importance to develop strategies for early identification, prevention and control of MRSA in this population of patients. Objectives: to detect MRSA in patients with liver diseases, in addition to observe the phenotypic and molecular characteristics of MRSA isolates in this group of patients. Methods: nasal and groin swabs were collected from 126 patients pre-transplant and 64 liver transplanted patients. The swabs were designed to microbiological culture and also to direct extraction of DNA. Determined the Minimum Inhibitory Concentration of 10 antimicrobials of all MRSA isolates which were also submitted to M-PCR of coA/mecA, characterization of SCCmec, PFGE and spa typing. DNA samples were also submitted to PCR of 16S, M-PCR of coA/mecA and characterization of SCCmec. Results: according to microbiological culture, 12% of swabs showed growth of MRSA, resulting in 44 MRSA isolates. All isolates were resistant to oxacillin, penicillin and vancomycin susceptible; all amplified the coA and mecA genes; SCCmec type II and spa t002 predominated in both groups; in addition there was a cluster among isolates, which was related to clone New York / Japan. Furthermore Brazilian Endemic Clone (BEC) was also related to 4 post transplantation isolates. 98% of DNA samples amplified 16S gene; M-PCR identified the presence of MRSA in 71% of DNA samples and 61% of the samples had the characterization of SCCmec. SCCmec type II was predominant in the two study groups. Conclusion: a high proportion of patients with liver disease are colonized with MRSA. Liver transplant patients are more colonized that cirrhotic patients by culture method. M-PCR CoA / mecA directly from swabs was more sensitive than microbiological culture to identify MRSA. Moreover, the PFGE shown to have a higher discriminatory power than spa typing and there was no good concordance between PFGE patterns and spa types. This study also demonstrated that there is a change of MRSA clones in our hospital, due to the replacement of the clone BEC by NY/Japan clone in the last decade
39
Johnson, Colin Wolcott. "Comparative Susceptibility and Mechanisms of Resistance to Host Defense Peptides in Daptomycin-Susceptible and Non-Susceptible Clinical Isolates of Staphylococcus aureus." Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/cmc_theses/1303.
Full textAbstract:
Host defense peptides (HDPs) provide innate immune defense against invasive S. aureus infection. Recent studies suggest potential cross-resistance between HDPs and the lipopeptide antibiotic, daptomycin (DAP). Isolates that exhibit DAP non-susceptible phenotypes may have virulence advantages and pose challenges to effective treatment. The current studies were performed to compare the efficacies and mechanisms of action of native and engineered HDPs vs. clinical S. aureus strain pairs which differed in susceptibility to daptomycin in vitro. Ultrasensitive radial diffusion and multi-colored flow cytometry were employed to analyze distinctive susceptibilities and mechanisms of resistance, respectively. Overall efficacies were greater vs. DAP-susceptible (DSSA) vs. DAP non-susceptible (DNSA) S. aureus isolates for some but not all HDPs. Efficacy profiles of certain HDPs were influenced by pH, regardless of whether the particular isolate was DSSA or DNSA phenotype. Mechanistically, DSSA and DNSA isolates differed in responses to specific HDPs regarding cell energetics, membrane permeability, cytoplasm membrane turnover, and cell death protease induction. DSSA and DNSA strain pairs exhibited non-identical mechanisms of resistance to HDPs. At pH 7.5, as expected, HDPs hNP-1 and RP-1 exerted significantly greater efficacy on susceptible control strain ISP479C vs. its resistant counterpart ISP479R. These data suggest different mechanisms of HDP resistance are active in differing DNSA strains. These preliminary results are under further investigation, as are the genetic determinant(s) that may emerge during infection. If substantiated, these findings would imply multiple modes of survival of S. aureus in the face of DAP or HDPs.
40
Salaam-Dreyer, Zubeida. "Genotypic characterization of Staphylococcus aureus isolates causing bacteraemia in patients admitted to Tygerberg Hospital, Western Cape Province, South Africa." Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4095.
Full textAbstract:
Thesis (MScMedSc (Pathology. Medical Microbiology))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: S. aureus causes serious infections in the hospital and community settings. The rate of MRSA infections are rapidly increasing worldwide. Currently, at Tygerberg hospital, approximately a third of S. aureus isolates are MRSA. This was the first epidemiological study of S. aureus conducted at Tygerberg Hospital that included prospective clinical data on patients with S. aureus bacteraemia together with spa typing of strains and the detection of the mecA and pvl genes in a multiplex PCR. Clonal cluster groups of S. aureus isolates were obtained by BURP analysis and compared to international important clones. The molecular epidemiology of hospital acquired (HA), health-care associated (HCA) and community acquired (CA) S. aureus bacteraemic strains at this hospital was examined. Lastly, repeat isolates of patients were collected to analyse any possible organism-related factors associated with persistent and recurrent bacteraemia. We investigated a total number of 113 S. aureus strains from 104 patients (70% MSSA, 30% MRSA). Repeat strains consisted of nine isolates (from 5 patients). All isolates were obtained from blood cultures collected during the period March 2008 to May 2009. Phenotypic and genotypic detection of methicillin resistance correlated well. According to the literature, most CA-MRSA strains are distinguishable from HA-MRSA strains based upon the presence of the PVL toxin. However, no CA-MRSA was detected in our study, therefore the association between HA-MRSA versus CA-MRSA strains could not be analysed. In this study, CA-MSSA was identified in 22% of all MSSA isolates versus 0% CA-MRSA. PVL positive strains were found in 22.7% of all MSSA isolates with no detection in MRSA isolates. It was noted that MRSA strains clustered in spa CC-701 and CC-012, whereas CC-002 only contained MSSA strains. Likewise HA-strains representing the majority of MRSA strains also clustered in spa CC-701 and CC-012. Forty nine spa types were identified in 89.3% of all isolates, whereas 9.7% of these strains were non-typeable. Five novel spa types were revealed. We detected a diverse number of spa-types that correlated to international clones. The most predominant spa type found in our setting was t037 (only in MRSA), followed by t891. According to the literature, t037 is associated to the Brazilian/Hungarian clone (SCCmec type III; ST 239). Our findings, as well as other South African studies, indicate that t037 has been identified in clinical strains from numerous provinces in South Africa. Interestingly, all isolates from spa type t891 were PVL positive MSSA. Bacteraemia cases were predominantly related to catheter sepsis, followed by skin and soft tissue infections (SSTI). Only one persistent bacteraemia case was identified related to a HA-SSTI. Recurrent bacteraemia cases were found in patients on dialysis for chronic renal failure and in burns patients related to intravascular catheter infections. The local epidemiology of S. aureus and the prevalence rate of different strains are important to investigate. The information provided contributes to the epidemiology of staphylococcal strains causing bacteraemia in our setting. These insights are useful for optimal diagnostic and therapeutic measures. The techniques developed can be used to identify outbreaks and recurrent infections.
AFRIKAANSE OPSOMMING: S. aureus veroorsaak ernstige infeksies in die hospitaalomgewing en in die gemeenskap. Wêreldwyd, neem metisillien-weerstandige S. aureus (MRSA) infeksies vinnig toe. Huidiglik by Tygerberg hospitaal is ongeveer ‘n derde van S. aureus isolate MRSA. Hierdie is die eerste epidemiologiese studie by Tygerberg hospitaal wat prospektiewe kliniese data van pasiënte met S. aureus bakteremie saam met spa tipering en aantoning van die mecA en pvl gene in ‘n multipleks PKR insluit. Klonale groepe (spa-CC) van MRSA en MSSA isolate is deur BURP analise verkry, en vergelyk met internasionaal belangrike klone. Die molekulêre epidemiologie van hospitaalverworwe (HA), gesondheidsorgverworwe (HCA) en gemeenskapsverworwe (CA) S. aureus bakteremie by hierdie hospitaal is ondersoek. Laastens, oorspronklike en daaropvolgende herhaal isolate is gekollekteer om moontlike organisme- faktore geassosieerd met persisterende en herhalende bakteremiese episodes te analiseer. Ons het in totaal 113 S. aureus isolate van 104 pasiënte ondersoek (70% MSSA, 30% MRSA). Nege isolate (van 5 pasiënte) was herhaal isolate. Alle isolate was afkomstig vanaf bloedkulture wat gedurende die periode Maart 2008 tot Mei 2009 gekollekteer is. Fenotipiese en genotipiese aantoning van metisillien weerstandigheid het goed gekorreleer. Volgens die literatuur kan die meeste CA-MRSA isolate van HA-MRSA isolate onderskei word op grond van die teenwoordigheid van die PVL toksien. Geen CA-MRSA is egter in ons studie gevind nie, dus kon die assosiasie tussen HA-MRSA en CA-MRSA isolate nie ondersoek word nie. CA-MSSA was in 22% van alle MSSA geidentifiseer teenoor 0% CA-MRSA. PVL is in MSSA isolate gevind (22.7% van alle MSSA) maar glad nie in MRSA nie. Dit is opgemerk dat MRSA isolate hoofsaaklik in spa CC 701 en CC-012 kloongroepe voorkom, teenoor kloongroep CC-002 wat slegs MSSA isolate bevat het. Soortgelyk het HA-isolate wat die meerderheid van MRSA isolate verteenwoordig het ook in kloongroepe 1 & 2 gegroepeer. Nege-en-veertig spa tipes is geïdentifiseer in 89.3% of alle isolate en 9.7% was nie-tipeerbaar. Vyf nuwe spa tipes is getoon. Ons het ‘n diverse aantal spa-tipes geïdentifiseer wat met internasionale klone gekorreleer het. Die mees dominante spa tipe in ons omgewing was t037 (slegs in MRSA), gevolg deur t891. Volgens die literatuur word t037 met die Brasiliaanse/Hongaarse kloon geassosieer (SCCmec tipe III; ST 239). Ons bevindings, asook ander Suid Afrikaanse studies, dui aan dat t037 in kliniese isolate vanaf talle provinsies in Suid-Afrika aangetoon is. Van belang is dat al die isolate van spa tipe t891 MSSA en PVL positief was. Bakteremiese gevalle was hoofsaaklik geassosieer met kateter-sepsis, gevolg deur vel en sagteweefsel infeksies (SSTI). Slegs een persisterende bakteremiese geval was geïdentifiseer geassosieer met HA-SSTI. Herhalende bakteremiese episodes is in pasiënte op dialise vir kroniese nierversaking en in brandwonde pasiënte met intra-vaskulêre kateter infeksies aangetoon. Die lokale epidemiologie van S. aureus en die prevalensie koers van verskillende stamme is van belang. Hierdie inligting dra by tot kennis van die epidemiologie van stafilokokkale stamme wat in ons omgewing bakteremie veroorsaak. Hierdie insigte is nuttig vir optimale diagnostiese en terapeutiese riglyne. Die tegnieke wat ontwikkel is, kan gebruik word om uitbrake en herhalende infeksies te identifiseer.
41
Widerström, Micael. "Molecular epidemiology of coagulase-negative staphylococci in hospitals and in the community." Doctoral thesis, Umeå universitet, Klinisk bakteriologi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-34289.
Full textAbstract:
Background Coagulase-negative staphylococci (CoNS) and in particular Staphylococcus epidermidis have emerged as major pathogens primarily causing nosocomial infections in patients with indwelling medical devices. These infections are often caused by multidrug-resistant strains of S. epidermidis (MDRSE). Other clinical entities due to CoNS are lower urinary tract infections (UTI) in women and native valve endocarditis. The purpose of this work was to investigate the frequency of antibiotic resistance and the molecular epidemiology of both hospital and community-associated isolates of S. epidermidis in order to examine if certain clones are related to MDRSE infections. Furthermore, we aimed to explore if specific clones of S. saprophyticus are associated with UTI in women. Methods A total of 359 hospital-associated methicillin-resistant isolates of CoNS obtained from 11 hospitals in northern Europe and 223 community-associated staphylococcal isolates were examined. Furthermore, 126 isolates of S. saprophyticus isolated from women with uncomplicated UTI from five different locations in northern Europe were analyzed. Pulsed-field gel electrophoresis (PFGE) was used for genotyping. Additionally, some of the S. epidermidis isolates were analyzed with multilocus sequence typing (MLST). Antibiotic susceptibility was determined for all isolates by the disc diffusion test. Results 293 of the 359 (82%) hospital-associated and 124 of the 223 (56%) community-associated isolates belonged to the species S. epidermidis. Among the hospital-associated S. epidermidis isolates, two dominating PFGE types (type A and B) were distinguished, comprising 78 (27%) and 51 (17%) isolates, respectively. Type A, which was detected in a Norwegian and eight Swedish hospitals, corresponded with a novel sequence type (ST215). Type B was discovered in a German, a Danish and seven Swedish hospitals and corresponded with ST2. In contrast, community-associated isolates of S. epidermidis were genetically extremely diverse with no predominating genotype, and showed a low rate of antibiotic resistance; only two (1.6%) methicillin-resistant strains were detected. Among 126 analyzed isolates of S. saprophyticus, 47 different PFGE profiles were identified. Several clusters of genetically highly related isolates were detected among isolates obtained from different locations and periods of time. Conclusion We have demonstrated the occurrence, persistence and potential dissemination of two multidrug-resistant S. epidermidis (MDRSE) genotypes, including a novel sequence type (ST215), within hospitals in northern Europe. Community-associated isolates of S. epidermidis showed a low rate of methicillin-resistance and were genetically heterogeneous. These results indicate that MDRSE by large are confined to the hospital setting in our region. Moreover, although the S. saprophyticus population was quite heterogeneous, indistinguishable isolates of S. saprophyticus causing lower UTI in women were identified in different countries 11 years apart, indicating the persistence and geographical spread of some clones of S. saprophyticus.
42
McBryde, Emma Sue. "Mathematical and statistical modelling of infectious diseases in hospitals." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16330/.
Full textAbstract:
Antibiotic resistant pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant enterococci (VRE), are an increasing burden on healthcare systems. Hospital acquired infections with these organisms leads to higher morbidity and mortality compared with the sensitive strains of the same species and both VRE and MRSA are on the rise worldwide including in Australian hospitals. Emerging community infectious diseases are also having an impact on hospitals. The Severe Acute Respiratory Syndrome virus (SARS Co-V) was noted for its propensity to spread throughout hospitals, and was contained largely through social distancing interventions including hospital isolation. A detailed understanding of the transmission of these and other emerging pathogens is crucial for their containment. The statistical inference and mathematical models used in this thesis aim to improve understanding of pathogen transmission by estimating the transmission rates of contagions and predicting the impact of interventions. Datasets used for these studies come from the Princess Alexandra Hospital in Brisbane, Australia and Shanxi province, mainland China. Epidemiological data on infection outbreaks are challenging to analyse due to the censored nature of infection transmission events. Most datasets record the time on symptom onset, but the transmission time is not observable. There are many ways of managing censored data, in this study we use Bayesian inference, with transmission times incorporated into the augmented dataset as latent variables. Hospital infection surveillance data is often much less detailed that data collected for epidemiological studies, often consisting of serial incidence or prevalence of patient colonisation with a resistant pathogen without individual patient event histories. Despite the lack of detailed data, transmission characteristics can be inferred from such a dataset using structured HiddenMarkovModels (HMMs). Each new transmission in an epidemic increases the infection pressure on those remaining susceptible, hence infection outbreak data are serially dependent. Statistical methods that assume independence of infection events are misleading and prone to over-estimating the impact of infection control interventions. Structured mathematical models that include transmission pressure are essential. Mathematical models can also give insights into the potential impact of interventions. The complex interaction of different infection control strategies, and their likely impact on transmission can be predicted using mathematical models. This dissertation uses modified or novel mathematical models that are specific to the pathogen and dataset being analysed. The first study estimates MRSA transmission in an Intensive Care Unit, using a structured four compartment model, Bayesian inference and a piecewise hazard methods. The model predicts the impact of interventions, such as changes to staff/patient ratios, ward size and decolonisation. A comparison of results of the stochastic and deterministic model is made and reason for differences given. The second study constructs a Hidden Markov Model to describe longitudinal data on weekly VRE prevalence. Transmission is assumed to be either from patient to patient cross-transmission or sporadic (independent of cross-transmission) and parameters for each mode of acquisition are estimated from the data. The third study develops a new model with a compartment representing an environmental reservoir. Parameters for the model are gathered from literature sources and the implications of the environmental reservoir are explored. The fourth study uses a modified Susceptible-Exposed-Infectious-Removed (SEIR) model to analyse data from a SARS outbreak in Shanxi province, China. Infectivity is determined before and after interventions as well as separately for hospitalised and community symptomatic SARS cases. Model diagnostics including sensitivity analysis, model comparison and bootstrapping are implemented.
43
BARROS, Mércia Rodrigues. "Epidemiologia molecular das infecções por Mycoplasma ssp., Escherichia coli e Staphylococcus spp., em frangos de corte e poedeiras comerciais no estado de Pernambuco." Universidade Federal Rural de Pernambuco, 2011. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/5768.
Full textAbstract:
Submitted by (edna.saturno@ufrpe.br) on 2016-10-19T14:56:21Z
No. of bitstreams: 1
Mercia Rodrigues Barros.pdf: 1115649 bytes, checksum: deca3723de48b7c3ba11045f77777fa2 (MD5)Made available in DSpace on 2016-10-19T14:56:21Z (GMT). No. of bitstreams: 1 Mercia Rodrigues Barros.pdf: 1115649 bytes, checksum: deca3723de48b7c3ba11045f77777fa2 (MD5) Previous issue date: 2011-02-02
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
This investigation had the objective of studying the molecular epidemiology of infections by Mycoplasma spp., Escherichia coli and Staphylococcus spp., in broilers and commercial layers of the state of Pernambuco. A hundred and twenty birds were used from 24 flock of which 55 healthy broilers, 35 broilers and 30 commercial layers with respiratory and digestive signs. For the study of Mycoplasma spp., the bacteriological exam, the Polymerase Chain Reaction (PCR) and Nested-PCR were used. For the isolation of Escherichia coli the medium Eosine Methylene Blue Agar (EMB) was used. The pathogenicity test in vitro was carried out in Congo Red magnesium oxalate agar while the PCR was used, to evaluate the presence of virulence genes and the phylogenetic determination of groups A, B1, B2 and D. For the study of citotoxicity, the samples were inoculated in Vero cells. For the detection of plasmids, the extraction of DNA and the visualization of the plasmid profile was used. For Staphylococcus spp., isolation the bacteriological exam was used, with biochemical proof of species identification. The formation of the biofilm Congo Red Agar (ACR), and the detection of the mecA gene by PCR were verified. For Escherichia coli and Staphylococcus spp., a resistance profile was carried out through tests of disc diffusion and Minimum Inhibitory Concentration (MIC). In the PCR for Mycoplasma spp., it was observed that seven (29.17%) samples were positive for MS and one (4.17%) for MG, in samples of birds with respiratory signs, the positive sample was further confirmed as vacinal strain MG-F; in the bacteriological exam all samples were negative. From the 35 isolated Escherichia coli submitted to PCR, the number of positive E coli isolates for virulence genes of were: iss (16), iutA (10), hlyF (17), ironN (11), ompT (16), crl (10), fimA (14), tsh (5), papA (2), csgA (0) and iucA (2). They were phylogenetically classified into groups A (71.42%) and B1 (28.58%). The presence of hemolysis in agar blood was superior to the detection of the hlyF gene by the PCR. The pathogenicity test in Congo Red agar showed five (14.29%) positive isolated E coli, and for the cytotoxicity evaluation in vitro, in Vero cells, all the isolated E coli were negative. On the resistance profile to antibiomicrobials, it was observed that 33 (94.28%) of the E coli isolates were resistant to three or more antibiotics and that lincomicine presented the highest percentage of resistance (100%). On the CIM, multiresistance to various antimircrobials was observed. With respect to the plasmids, a frequency of 80.0% (28/35) was observed in E. coli isolates, where 16 E. coli isolates presented plasmid of 88 MDa. From the 24 processed samples 16 Staphylococcus isolates were, five being coagulasis-positive (SCP) and 11 coagulasis-negative (SCN). The biofilm production test, six (37.5%) isolates were positive. Regarding PCR for the detection of the mecA gene, all the isolates were negative. It was observed that 15 isolates presented a multiresistance profile to antimicrobials. Based on the results, these bacteria participate in the respiratory disease of the studied chickens populations and they must be considered in the control and treatment measures used in aviculture, together with the performance of in vitro tests.
Objetivou-se com este trabalho estudar a epidemiologia molecular das infecções por Mycoplasma spp., Escherichia coli e Staphylococcus spp., em frangos de corte e poedeiras comerciais no Estado de Pernambuco. Foram utilizadas 120 aves provenientes de 24 granjas, das quais 55 frangos de corte sadios, 35 com sinais respiratórios e 30 poedeiras comerciais com sinais respiratórios e digestivos. Para a pesquisa de Mycoplasma spp., utilizou-se o exame bacteriológico e a reação em cadeia da polimerase (PCR) e Nested-PCR. Para o isolamento de Escherichia coli foi utilizado o meio ágar Eosina Azul de Metileno (EMB), o teste de patogenicidade in vitro foi realizado em ágar oxalato de magnésio acrescido de vermelho congo, enquanto a PCR foi realizada para avaliar a presença de genes de virulência e determinação filogenética dos grupos em A, B1, B2 e D. Para o estudo de citotoxicidade, as amostras foram inoculadas em células Vero e para a detecção de plasmídios foi utilizada a extração de DNA e visualização do perfil plasmidial. Para o isolamento de Staphylococcus spp., utilizou-se o exame bacteriológico, com provas bioquímicas para a identificação das espécies. Verificou-se a formação de biofilme em ágar Vermelho Congo (ACR), e detecção do gene mecA pela PCR. Para Escherichia coli e Staphylococcus spp., realizou-se perfil de resistência através dos testes de disco difusão e Concentração Inibitória Mínima (CIM). Na PCR para Mycoplasma spp., observou-se que sete (29,17%) amostras foram positivas para MS e uma (4,17%) para MG em amostras de aves com sinais respiratórios, sendo a amostra positiva confirmada como cepa vacinal MG-F; no exame bacteriológico todas as amostras foram negativas. Dos 35 isolados de Escherichia coli submetidos a PCR, o número de isolados positivos para os genes de virulência foi: iss (16), iutA (10), hlyF (17), ironN (11), ompT (16), crl (10), fimA (14), tsh (5), papA (2), csgA (0) e iucA (2). Foram classificados filogeneticamente nos grupos A (71,42%) e B1 (28,58%). A presença de hemólise em ágar sangue foi superior à detecção do gene hlyF pela PCR. O teste de patogenicidade em ágar vermelho congo revelou cinco (14,29%) isolados positivos e para avaliação da citotoxicidade in vitro em células Vero todos os isolados foram negativos. No perfil de resistência aos antibiomicrobianos observou-se que 33 (94,28%) isolados foram resistentes a três ou mais antibióticos e a lincomicina apresentou o maior percentual de resistência (100%). Na CIM observou-se multirresistência a vários antimicrobianos. Quanto aos plasmídios observou-se frequência de 80,0% (28/35) nos isolados de E. coli, onde 16 isolados apresentaram plasmídio de 88 MDa. Das 24 amostras processadas foram isolados 16 Staphylococcus, sendo cinco coagulase-positiva (SCP) e 11 coagulase negativa (SCN), e no teste de produção de biofilme, seis (37,5%) isolados foram positivos. Na PCR para detecção do gene mecA todos os isolados foram negativos. Observou-se que 15 isolados apresentaram perfil de multirresistência a antimicrobianos. Com base nos resultados obtidos, essas bactérias participam da doença respiratória na população estudada e devem ser consideradas nas medidas de controle e tratamento nos plantéis avícolas em conjunto com a realização de testes in vitro.
44
Barros, Priscila de Oliveira. "Avaliação da resposta imune a Staphylococcus aureus, Escherichia coli e Candida albicans em pacientes com neuromielite óptica e sua correlação com o grau de incapacidade neurológica." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=4909.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorA Neuromielite Óptica (NMO), anteriormente considerada como um subtipo de Esclerose Múltipla, é uma doença autoimune, inflamatória do sistema nervoso central, na qual o sistema imune ataca a mielina dos neurônios localizados nos nervos ópticos e medula espinhal, produzindo, então, mielite e neurite óptica simultânea ou sequenciais. A patogênese da neuromielite óptica é influenciada pela combinação de fatores genéticos e ambientais, incluindo agentes infecciosos. Diferentes doenças infecciosas podem tanto desencadear como exacerbar a autoimunidade. Portanto, o objetivo do presente estudo foi de analisar a responsividade imune in vitro a Escherichia coli, Staphylococcus aureus e Candida albicans em pacientes com NMO recorrente-remitente, e a correlacionar ao nível de incapacidade neurológica. Nesse contexto, a extensão da linfoproliferação e perfil de citocinas em resposta a S. aureus e C. albicans, em culturas de células mononucleares do sangue periférico (CMSP) foram similares entre pacientes com NMO e indivíduos saudáveis. Entretanto, maior proliferação de células T associada à elevada liberação de IL-1β, IL-6 e IL-17 foi observada em culturas de células derivadas de pacientes com NMO quando estimuladas com E. coli. Ademais, nessas culturas, a produção de IL-10 foi significativamente menor quando comparada ao grupo controle. Ensaios conduzidos em culturas de CMSP depletadas de diferentes subtipos de linfócitos demonstraram que, enquanto células T CD4+ e T CD8+ produzem IL-6 em resposta a E. coli, a produção de IL-17 foi praticamente restrita às células T CD4+. Os níveis de IL-6 e IL-17 in vitro induzidos por E. coli foram correlacionados positivamente às incapacidades neurológicas. Essa maior tendência a produzir citocinas relacionadas ao perfil Th17 foi diretamente associada aos níveis de IL-23 produzidos por monócitos ativados com LPS. De modo interessante, níveis elevados de LPS foram quantificados no plasma de pacientes com NMO e estes foram correlacionados aos níveis plasmáticos de IL-6. Em conclusão, nossos resultados sugerem que uma maior responsividade a E. coli poderia estar envolvida na patogênese da NMO. Esse tipo de investigação é muito importante pois inibidores da ligação ou sinalização do TLR poderiam ser considerados terapias com grande potencial como adjuvantes no tratamento de pacientes com NMO.
Neuromyelitis optica (NMO), once considered as a subtype of Multiple Sclerosis, is an autoimmune, inflammatory disorder of the central nervous system in which the immune system attacks myelin of the neurons located at the optic nerves and spinal cord, thus producing a simultaneous or sequential optic neuritis and myelitis. The pathogenesis of neuromyelitis optica (NMO) is influenced by a combination of genetic and environmental factors, including infectious agents. Different infectious diseases can both trigger or exacerbate autoimmunity. Therefore, the objective of the present work was to evaluate the in vitro immune responsiveness to Escherichia coli, Staphylococcus aureus and Candida albicans in remittent-recurrent NMO patients, and correlate it to the level of neurological disability. In this context, the extent of lymphoproliferation and cytokine profile in response to S. aureus- and C. albicans-stimulated peripheral blood mononuclear cells (PBMC) cultures was similar between NMO patients and healthy individuals. Nevertheless, a higher in vitro T cell proliferation associated with elevated IL-1β, IL-6 and IL-17 release was observed in NMO-derived E. coli-stimulated cell cultures. Additionally, in these cultures, the IL-10 production was significantly lower as compared with control group. Experiments performed with PBMC cultures depleted with different lymphocytes subsets demonstrated that, while both CD4+ and CD8+ T cells produced IL-6 in response to E. coli, the IL-17 production was mainly depended with CD4+ T cells.The in vitro E.coli-induced IL-6 and IL-17 levels were positively related with neurological disabilities. This higher tendency in producing Th-17-related cytokines was directly associated with IL-23 levels produced by LPS-activated monocytes. Interestingly, elevated LPS levels were quantified in the plasma of NMO patients and they were related to plasmatic levels of IL-6. In conclusion, our results suggest that a higher Th17-responsiveness to E. coli could be involved in the NMO pathogenesis. This kind of investigation is very important because inhibitors of TLR binding or signaling could be considered as great potential therapeutics as adjuvant in the treatment of NMO patients.
45
Lopez, Gerardo Urquijo. "Transfer of Microorganisms from Fomites to Hands and Risk Assessment of Contaminated and Disinfected Surfaces." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/272839.
Full textAbstract:
It is now widely accepted that surface contamination plays an important role in the transmission of both respiratory and gastrointestinal infections in the domestic environment and community setting. The efficiency of transfer of a pathogen to the hand from a fomite is important in modeling transmission in microbial risk assessment models. The objective of this study was to use published literature to assess the role of fomites and hands in disease transmission, and to conduct fomite-to-finger transfer studies from various porous and nonporous fomites under different relative humidity condition using non-pathogenic strains of Escherichia coli, Staphylococcus aureus, MS2 coliphage, Bacillus thuringiensis spores, and poliovirus 1; to evaluate the persistence of bacteria and viruses on surfaces; to examine bacteria and virus transfer from treated surfaces; and to conduct a foodborne quantitative microbial risk assessment using Campylobacter jejuni from the data obtained in these studies. It was found that numerous factors influence the transfer efficiency of microorganisms, with moisture being the most important, with greater transfer under humid conditions. Other factors influencing transfer include drying time, contact time, pressure, friction, type of material, and porosity of the fomite. Percent transfer was greater under high relative humidity for both porous and nonporous surfaces. Most organisms on average had greater transfer under high relative humidity (40 - 65%) compared to low relative humidity (15 - 32%). Relative humidity and fomite type influenced the survival of all studied organisms; survival was greater on nonporous surfaces than those for porous surfaces. Test organisms were reduced up to 99.997% on the fomites after the surfaces were wiped with a disinfectant wipe. Microbial fomite-to-finger transfer from disinfectant wipe-treated surfaces were, lower than from non-treated surfaces. The disinfectant-wipe intervention reduced the risk of Campylobacter infection, illness, and death by 2 to 3 orders on all fomites. The disinfectant-wipe intervention reduced the annual risk of illness below the reported national average of diagnosed Campylobacteriosis cases 1.3E-04. This risk assessment demonstrates that the use of disinfectant wipes to decontaminate surface areas after chicken preparation reduces the risk of C. jejuni infections up to 99.2%.
46
Rocha, Larissa Carneiro. "Estudo de marcadores de prognóstico em crianças com doença flaciforme e sua associação com colonização de nasofaringe e orofaringe." reponame:Repositório Institucional da FIOCRUZ, 2011. https://www.arca.fiocruz.br/handle/icict/4230.
Full textAbstract:
Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2012-07-20T21:34:48Z
No. of bitstreams: 1
Larissa Carneiro Rocha.pdf: 1632038 bytes, checksum: 82deed6171da78f07c96b948629b2896 (MD5)Made available in DSpace on 2012-07-20T21:34:48Z (GMT). No. of bitstreams: 1 Larissa Carneiro Rocha.pdf: 1632038 bytes, checksum: 82deed6171da78f07c96b948629b2896 (MD5) Previous issue date: 2011
Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, Bahia, Brasil
A doença falciforme (DF) possui prevalência mundial elevada e manifestação clinicamente variável, sendo que as infecções constituem risco elevado e causa de óbito nas crianças diagnosticadas com anemia falciforme (HbSS). A colonização da nasofaringe pode ser fator importante para a ocorrência de doença local ou sistêmica. O Streptococcus pneumoniae é um patógeno de importância epidemiológica mundial e causador de infecções entre os pacientes com DF. A prevalência da colonização pelo pneumococo em nasofaringe varia de acordo com a população estudada e condições ambientais. O Staphylococcus aureus também pode colonizar a nasofaringe, além de causar infecção de pele e tecidos moles, pneumonia, septicemia e infecções ósteo-articulares. Diferentes biomarcadores têm sido associados à modulação clínica na DF e eles são comumente associados à hemólise e inflamação. O presente estudo teve como objetivo estabelecer o perfil de biomarcadores em indivíduos com DF associando-os ao perfil de colonização nasofaríngea e orofaríngea, com ênfase para os marcadores de infecção e hemólise que possam estar associados ao prognóstico clínico dda doença. As análises bioquímicas foram realizadas para a avaliação do perfil lipídico, hepático, inflamatório e hemolítico; marcadores clássicos de biologia molecular, como a talassemia α, os haplótipos ligados aos genes da globina beta e os polimorfismos no gene da mieloperoxidase foram também investigados. Desta forma, foi desenvolvido um estudo de corte transversal, com casuística composta por 154 pacientes com DF em idade pediátrica e em estado estável da doença, sendo 68,2% (105/154) HbSS e 31,8% (49/154) com doença SC (HbSC), todos provenientes do estado da Bahia. As crianças HbSS apresentaram diferenças significativas na grande maioria das variáveis laboratoriais analisadas e associadas ao metabolismo lipídico, renal, hepático e à hemólise e inflamação, quando comparadas ao grupo HbSC e ao controle saudável. A colonização em nasofaringe/orofaringe pelo S. pneumoniae esteve presente em 14 (9,6%) pacientes e pelo S. aureus em 81(56,6%) pacientes. Quanto ao perfil de sensibilidade dos isolados de pneumococos da população estudada, não foi observado o aumento da resistência pneumocócica à penicilina. A avaliação de modelos de análise multivariada demonstrou que a presença de colonização nasofaríngea e orofaríngea esteve associada à ocorrência de infecção juntamente com a contagem de leucócitos, sendo que o genótipo exibido pelo paciente foi fator de risco para a ocorrência de pneumonia. Os mesmos modelos apontaram o envolvimento dos polimorfonucleares neutrófilos na ocorrência de vaso-oclusão. Os resultados demonstram que os pacientes colonizados em nasofaringe pelo S. pneumoniae e pelo S. aureus apresentaram elevação dos valores de HCM, VCM, AST, ALT e Ferritina; investigações rotineiras de biomarcadores clássicos associados ao estudo da colonização de nasofaringe e orofaringe podem ter papel importante no acompanhamento da evolução clinica de indivíduos com DF, uma vez que os achados significativos sugerem que a presença de colonização tem papel importante na modulação dos eventos hemolítico, inflamatório e infeccioso presentes na doença.
The sickle cell disease (SCD) has a high prevalence worldwide and a variable clinical manifestation and infections are considered an event of high risk and cause of death in children diagnosed with sickle cell anemia (HbSS). The colonization of nasopharynx and oropharynx can be an important factor for the occurrence of local or systemic disease. The Streptococcus pneumoniae is a pathogen of epidemiological importance worldwide and cause of infection among SCD patients. The Staphylococcus aureus may also colonize the nasopharynx and may be cause of infection of skin and soft tissue infections, pneumonia, sepsis and osteo-articular infections. Different biomarkers have been associated with clinical modulation in SCD and they are commonly associated with hemolysis and inflammation. This study aimed to establish a profile of biomarkers in individuals with SCD in association with the profile of oropharyngeal and nasopharyngeal colonization, with emphasis on infection and hemolysis markers that may be associated with clinical prognosis. Biochemical analysis were performed to evaluate the lipid profile, liver, hemolytic and inflammatory markers and classical molecular biology, such as α-thalassemia, the haplotypes linked to the beta globin genes and polymorphisms in the myeloperoxidase gene were also investigated. Thus, it was developed a cross-sectional study and the casuistic was composed of 154 children with SCD in a steady-state, with 68.2% (105/154) HbSS and 31.8% (49/154) with SC disease (HbSC), all from the state of Bahia. HbSS children showed significant differences in almost every mean values analyzed for variables associated with lipid metabolism, kidney, liver and hemolysis and inflammation when compared to HbSC and control group. In the present study there was colonization in the nasopharynx / oropharynx by S. pneumoniae in 14 (9.6%) patients and by S. aureus in 81 (56.6%) patients. The profile of sensitivity of pneumococcal isolated from the studied population did not show an increase in pneumococcal resistance to penicillin. The evaluation of models of multivariate analysis showed that the presence of oropharyngeal and nasopharyngeal colonization was associated with the occurrence of infection and white blood cell count, and the patient genotype was a risk factor for the occurrence of pneumonia. The same models indicated the involvement of polymorphonuclear neutrophils in the occurrence of vaso-occlusion. The results presented in this study demonstrate that patients colonized in the nasopharynx by S. pneumoniae and S. aureus have elevated values of MCH, MCV, AST, ALT and ferritin, suggesting that a routine investigation of biomarkers associated with the classic study of the colonization of the nasopharynx and oropharynx may play a role in monitoring the clinical course of patients with SCD, once that significant findings described here suggest that the presence of colonization plays an important role in modulation of hemolytic events, inflammatory state, and infectious presented by patients.
47
Maurin, Max. "Rôle du pH phagolysosomial dans l'action des antibiotiques sur les bactéries intracellulaires." Paris 7, 1994. http://www.theses.fr/1994PA077067.
Full textAbstract:
L'absence d'activité d'un antibiotique sur un microorganisme à vie intracellulaire peut correspondre à son incapacité à pénétrer dans la cellule eucaryote, a une localisation subcellulaire différente de celle du microorganisme considéré, ou à une inactivation intracellulaire de l'antibiotique. Nous avons testé l'hypothèse d'une inactivation des antibiotiques dans le milieu phagolysosomial acide, à travers deux modèles de bactéries vivant dans ce compartiment cellulaire ; staphylococcus aureus et coxiella burnetii. Nous avons vérifié dans un premier temps la possibilité d'alcaliniser le ph phagolysosomial par l'utilisation d'agents lysosomotropes. Nous avons ensuite démontré l'effet bactéricide de l'association des agents lysosomotropes aux antibiotiques, alors que ni les agents lysosomotropes ni les antibiotiques n'étaient bactéricides isolement. L'alcalinisation phagolysosomiale est le mécanisme par lequel les agents lysosomotropes ont rétabli l'activité des antibiotiques. Nous avons par ailleurs élaboré un nouveau modèle expérimental d'endocardite à staphylococcus aureus chez le cobaye. Du fait de la méthodologie utilisée, ce modèle est plus proche de l'endocardite sur valve native. Notre but final est de créer un modèle d'endocardite à coxiella burnetii. Ce modèle permettrait notamment de tester in vivo l'activité de l'association des agents lysosomotropes aux antibiotiques.
48
Olivier, Dedré. "The influence of thermal and nonthermal food preservation methodologies on the liberation and ultrastructure of bacterial endotoxins." Thesis, Bloemfontein : Central University of Technology, Free State, 2010. http://hdl.handle.net/11462/123.
Full textAbstract:
Thesis (D. Tech. (Biomed. Tech.)) -- Central University of Technology free State, 2010Consumer demands for fresh, microbiologically safe foods with high organoleptical and nutritional quality has led to the development of novel food preservation technologies as alternatives or enhancements to traditional preservation techniques. An example of these novel preservation technologies is high hydrostatic pressure (HHP) processing. It involves the applications of static pressure of 50 to 1 000 mega Pascals (MPa) to solid or packaged liquid foods, with varying holding times. The combination of factors to enhance preservation is increasingly being used in industry, e.g. the use of different temperatures and additives (hurdles) can enhance the preservative effect of HHP. In this study the influence of HHP on organism viability and growth response was assessed. The organisms evaluated included Escherichia coli O111, Listeria monocytogenes (UAFSBCC) and Staphylococcus aureus (ATCC 25923), in peptone water, which was subjected to HHP of 200 MPa for 15 minutes at 8 and 50 ºC respectively. Subsequent to the mentioned pressurisation, sub-culturing was performed and growth responses were evaluated at 0, 6, 18, 24, 30, 42 and 48 hours. Bacterial survival and growth response was measured by means of intact cell count, colony forming units and optical density. From the results it was eminent that bacterial cells were only sublethally injured and were able to repair within 48 hours of enriched sub-culturing. E. coli O111 proved to be most sensitive to HHP with Staphylococcus aureus (ATCC 25923) most resistant. This study also proved that bacterial concentration and inactivation rate are inversely proportionate to each other. Subsequent to growth and cell repair assessments, E. coli O111 was selected as a model to evaluate the effect of sublethal HHP on the liberation and toxicity of bacterial endotoxins (free and cell wall bound). It is also known that different extraction procedures extract different lipopolysaccharides (LPS) fractions and therefore LPS was extracted from the test broth by a combination method of Folch, Lees & Sloane-Stanley, and Venter and Ivanov. The extraction yielded a biphasic system, LPS with reduced lipid content in the upper phase (aqueous) and LPS with increased lipid content in the lower phase (organic). Following extraction the Limulus amebocyte lysate (LAL) test was performed to quantify the concentration (assumed) of LPS in the aqueous and organic phases. Free LPS was detected within six hours in the supernatant in the high and low bacterial loads, moreover the toxicity response of post HHP cell damage was more pronounced at 50 ºC (hurdle) than that observed for the treatments at 8 ºC (hurdle) and more so in the organic phases. The latter implied that HHP not only resulted in quantity LPS variation but also in structural change. However membrane repair was apparently complete after 48 hours, as differences in toxicity were no longer evident. Furthermore, the use of a porcine IL-6 ELISA assay was evaluated as an alternative for the customary LAL as a biomarker for pyrogenic substances in matrixes. Porcine whole blood was challenged for IL-6 production by LPS in the samples from the organic and aqueous systems. A porcine IL-6 enzyme-linked immunosorbent assay was used to assess IL-6 expression in whole blood after being challenged with LPS. From the results it emanated that HHP caused in a change in LPS structure which resulted in a decreased IL-6 expression in whole blood, indicating that structural adaptation of the cell membrane in response to HHP influenced the ability of LPS to stimulate macrophages and monocytes. Therefore, further research and development would be required to evaluate the influence of post HHP LPS on human IL-6 expression. When comparing the porcine IL-6 with the LAL no correlation in toxicity could be established in any of the treatment parameters. Finally it can be concluded that HHP had an influence in the structural morphology of LPS. These structural changes could result in LPS being more toxic, it could also have an effect on the accuracy of immunological assessments, the ability to form biofilm, and susceptibility to phages.
49
Engelbrecht, Fredrika. "The antimicrobial susceptibility and gene-based resistance of Streptococcus Agalactiae (group B Streptococcus) in pregnant women in Windhoek (Khomas region), Namibia." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2238.
Full textAbstract:
Thesis (MTech (Biomedical Sciences))--Cape Peninsula University of Technology, 2015.BACKGROUND AND OBJECTIVES: Group B Streptococci (GBS) can asymptomatically colonise the vagina and rectum of women. Studies have shown that this bacterium is the leading cause of septicemia, meningitis and pneumonia in neonates. In Namibia no known studies have investigated GBS colonisation and the antibiotic resistance profile of GBS isolates in pregnant women. This study accessed the GBS colonisation rate amongst the pregnant women who attended the Windhoek Central Hospital Antenatal Clinic (Khomas region), in Namibia for a period of 13 months. Furthermore, using the VITEK 2 system, the GBS isolates were tested against the following antimicrobial substances; benzylpenicillin, ampicillin, clindamycin, erythromycin, tetracycline, vancomycin, cefotaxime, ceftriaxone, linezolid and trimethoprim/sulfamethoxazole. Penicillin G is the drug of choice in the majority of studies, and seems to be the most effective drug for intrapartum antibiotic prophylaxis (IAP). All the GBS isolates found in this study were also analysed for the presence of selected genes known to be associated with resistance to key antibiotics using specific primers within a polymerase chain reaction (PCR).
50
Forrester, Marie Leanne. "Epidemic models and inference for the transmission of hospital pathogens." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16419/.
Full textAbstract:
The primary objective of this dissertation is to utilise, adapt and extend current stochastic models and statistical inference techniques to describe the transmission of nosocomial pathogens, i.e. hospital-acquired pathogens, and multiply-resistant organisms within the hospital setting. The emergence of higher levels of antibiotic resistance is threatening the long term viability of current treatment options and placing greater emphasis on the use of infection control procedures. The relative importance and value of various infection control practices is often debated and there is a lack of quantitative evidence concerning their effectiveness. The methods developed in this dissertation are applied to data of methicillin-resistant Staphylococcus aureus occurrence in intensive care units to quantify the effectiveness of infection control procedures. Analysis of infectious disease or carriage data is complicated by dependencies within the data and partial observation of the transmission process. Dependencies within the data are inherent because the risk of colonisation depends on the number of other colonised individuals. The colonisation times, chain and duration are often not visible to the human eye making only partial observation of the transmission process possible. Within a hospital setting, routine surveillance monitoring permits knowledge of interval-censored colonisation times. However, consideration needs to be given to the possibility of false negative outcomes when relying on observations from routine surveillance monitoring. SI (Susceptible, Infected) models are commonly used to describe community epidemic processes and allow for any inherent dependencies. Statistical inference techniques, such as the expectation-maximisation (EM) algorithm and Markov chain Monte Carlo (MCMC) can be used to estimate the model parameters when only partial observation of the epidemic process is possible. These methods appear well suited for the analysis of hospital infectious disease data but need to be adapted for short patient stays through migration. This thesis focuses on the use of Bayesian statistics to explore the posterior distributions of the unknown parameters. MCMC techniques are introduced to overcome analytical intractability caused by partial observation of the epidemic process. Statistical issues such as model adequacy and MCMC convergence assessment are discussed throughout the thesis. The new methodology allows the quantification of the relative importance of different transmission routes and the benefits of hospital practices, in terms of changed transmission rates. Evidence-based decisions can therefore be made on the impact of infection control procedures which is otherwise difficult on the basis of clinical studies alone. The methods are applied to data describing the occurrence of methicillin-resistant Staphylococcus aureus within intensive care units in hospitals in Brisbane and London