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1
Jones, Eleanor. "Osmotic adaptations of Staphylococcus aureus." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310928.
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Fox, Paige McCarthy. "Characterization of Vancomycin Resistance in Staphylococcus Aureus." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd/1243.
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In the past decade, Staphylococcus aureus has developed two distinct vancomycin resistance mechanisms. First, the bacterium is capable of generating a thickened, poorly crosslinked cell wall that creates false targets. These targets cause vancomycin to bind at the periphery of the thickened peptidoglycan, allowing normal cell wall formation to continue at the cell membrane. Second, S. aureus has acquired genes from Enterococcus that encode an alternative stem peptide. The genes, known as van genes, alter the target of vancomycin, rendering vancomycin treatment ineffectual.In this work, we attempted to further characterize both mechanisms of vancomycin resistance. First, a potential link between up-regulated purine biosynthesis and increased vancomycin resistance due to a thickened cell wall was examined. Despite exploration of multiple mechanisms to increase purine levels within the cell, increased purine synthesis did not provide S. aureus with any advantage in the presence of vancomycin. However, during the investigation, purine biosynthesis in S. aureus was further characterized by confirming purr as the repressor of the purine pathway and demonstrating its sensitivity to mutation.Next, the relationship between homotypic oxacillin resistance and increased vancomycin resistance in the absence of the van genes was investigated. Vancomycin passage of two heterotypic methicillin resistant S. aureus (MRSA) caused these strains to convert to homotypic oxacillin resistance in the absence of oxacillin exposure. Additionally, conversion of heterotypic oxacillin resistant strains to homotypy by oxacillin passage increased strain survival in vancomycin. The SOS response was examined as the possible link between conversion to homotypic oxacillin resistance and increasing vancomycin resistance due to a thickened cell wall. The current study, however, detected no induction of the SOS response during vancomycin exposure.Lastly, the relationship between oxacillin resistance and vancomycin resistance due to the acquisition of the van genes was examined. In vitro and in vivo methods were utilized to determine the effectiveness of a combination of β-lactam antibiotics and vancomycin to treat vancomycin resistant S. aureus (VRSA) infections. Combination therapy provided a significant advantage over untreated control or either antibiotic alone in the rabbit model of endocarditis.
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Vance, Lindsey. "The Inhibitory Effects of a Novel Gel on Staphylococcus aureus Biofilms." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/honors/435.
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Antibiotic resistance is an ever-growing topic of concern within the medical field causing researchers to examine the mechanisms of resistance to develop new antimicrobials. Bacteria’s ability to form biofilms is one mechanism which aids in antimicrobial resistance. Staphylococcus aureus is of special interest as it is one of the most frequent biofilm-forming bacteria found on medical devices causing infections and posing dangerous threats in a clinical setting. A recently developed antimicrobial gel has been shown to have profound effects on treating bacterial infections and wound healing. This research is centered upon examining the antimicrobial effects of this gel on the three different stages of biofilm formation in clinical and laboratory strains of S. aureus. Through a series of experiments examining the effects this gel has on S. aureus at the stages of biofilm attachment, maturation, and dispersion, the gel has shown significant levels of inhibition. These findings indicate that the novel gel disrupts biofilm forming processes of S. aureus, which provides useful information for fighting infections in the medical field. Further research on the uses and effects of this new gel could lead possibility using the antimicrobial compound for a variety of clinical purposes.
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Johnson, Adam L. "Characterization of a Novel Protease in Staphylococcus aureus." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3943.
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A newly discovered cysteine protease, Prp, has been shown to perform an essential, site-specific cleavage of ribosomal protein L27 in Staphylococcus aureus. In Firmicutes and related bacteria, ribosomal protein L27 is encoded with a conserved N-terminal extension that must be removed to expose residues critical for ribosome function. Uncleavable and pre-cleaved variants were unable to complement an L27 deletion in S. aureus, indicating that this N-terminal processing event is essential and likely plays an important regulatory role. The gene encoding the responsible protease (prp) has been shown to be essential, and is found in all organisms encoding the N-terminal extension of L27. Cleavage of L27 by Prp represents a new target for potential antibiotic therapy. In order to characterize this protease, Prp has been overexpressed and purified. Using an assay we have developed, based on cleavage of a fluorogenic peptide derived from the conserved L27 cleavage sequence, we have undertaken an analysis of the enzyme kinetics and substrate specificity for Prp cleavage and tested predictions made based on a structural model using active-site mutants.
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Evans, Jane E. "The conjugation system of Staphylococcus aureus." Thesis, University of Oxford, 1986. https://ora.ox.ac.uk/objects/uuid:1c1f5c11-f854-4af5-b9cf-34fdf279fb28.
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A conjugation system in Staphylococcus aureus has been investigated and shown to be determined, at least in part, by genes carried on plasmids. Conjugation required cell-to-cell contact but not calcium ions. The frequency of conjugation depended on the recipient used and on the incubation conditions. Two conjugative plasmids were mapped by restriction enzyme analysis but experiments to clone the conjugation-determining region were unsuccessful although separate regions specifying gentamicin resistance, ethidium bromide resistance and cadmium resistance were cloned. The gentamicin resistance determinant was probably part of Tn4001. Deletion of various sized pieces of DNA from one of the plasmids resulted in reduction of its ability to specify conjugation but no specific part of this plasmid could be implicated in the process. Further experiments led to the conclusion that this particular plasmid (p8325-4) is probably not self-transmissible but transferred by a phage-mediated system. Strains of Staphylococcus aureus produced a pheromone-like substance that elicited a clumping response in Streptococcus faecalis but no evidence was found for the involvement of staphylococcal conjugative plasmids in this. The conjugative plasmid, p8325-2, mobilized a small plasmid (pT181) but not a chromosomal gene. Insertion of transposon Tn551 was used to produce mutants of the conjugative plasmid p8325-2. Some twenty-six mutants were studied and the position of Tn551 in them mapped. There were preferred regions of insertion for Tn551 and twenty out of the twenty-six mutants had altered ability to conjugate. One showed a significantly higher frequency of conjugation and the other nineteen, all with substantially lower frequencies of conjugation, were mapped to two well-separated regions of the plasmid. Similarity between the locations of these putative regions and those reported for some other conjugative plasmids from staphylococci is striking and suggests a common origin.
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Piemont, Yves. "Les Exfoliatines de Staphylococcus aureus." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37608872c.
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Griffin, Blakeley. "A Study of the Polymicrobial Inhibitory Interactions Between Alcaligenes faecalis and Staphylococcus aureus." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/honors/579.
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Members of the Staphylococcus genus are found as a part of normal microflora in humans and can commonly be found on the skin or in the nasal cavity. However, these microorganisms can cause serious and life-threatening opportunistic infections when there is a break in the physical barrier of skin. These infections have become difficult to treat as resistant strains emerge, particularly Methicillin Resistant Staphylococcus aureus (MRSA). MRSA has become a commonly acquired nosocomial infection which is difficult to treat with conventional antibiotics of the blactam class. Even Vancomycin, a last resort antibiotic, has been ineffective on some infections. Furthermore, S. aureus readily forms biofilms on implanted medical devices which establishes a hardy and difficult to treat infection. These biofilms serve as a point of infection to the bloodstream. Research involving polymicrobial interactions and the inhibitory effects of bacterial-bacterial interactions could be a starting point for the discovery of a new therapeutic treatment for infections. It has been shown in our lab that Alcaligenes faecalishas inhibitory effects on Staphylococcus aureusplanktonic growth. Therefore, in this study, we wanted to examine 1) The mechanism by which A. faecalisinhibitsS. aureus growth and 2) how A. faecalisimpacts the various phases of S. aureusbiofilm growth. It was found that A. faecalislikely inhibits S. aureususing a physical mechanism that requires close contact, rather than using a secreted molecule. However, a Type VI secretion system could also produce similar results. Further research involving the formation of mutants to find the gene allowing A. faecalisto inhibit S. aureuswas started, but no viable mutants were created during the course of this research. A. faecaliswas found to inhibit the formation of S. aureus biofilm growth, but when added to a mature S. aureusbiofilm, the slow growth rate of A. faecaliscould not overtake the quickly replicating S. aureus. Further research in the polymicrobial interactions between S. aureus and A. faecaliscould lead to a finding of a new therapeutic target for antibiotics or the use of A. faecalisin infections.
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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.
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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.
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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.
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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.
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Najar, A. G. "Protein exported by Staphylococcus aureus and the effect of some membrane modifying agents." Thesis, University of Kent, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383048.
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Krikler, S. J. "Carriage and attempted eradication of Staphylococcus aureus in an isolated community in Antarctica." Thesis, University of Aberdeen, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384403.
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This study was conducted on twenty-eight men at Halley Base, Antarctica, in total physical isolation from all other human contact from beginning March to end December 1983. Aims of study: observe S. aureus carriage in this community; monitor effects on carriage of topical antibacterials. Initially, weekly nasal, axillary and perineal swabs taken. From week 24 throat swabs taken from known nasal carriers. Two courses of antibacterials given to all subjects, regardless of carrier status. Two further courses given to known carriers. Eight subjects consistently carried own phage type throughout study, despite application of antibacterials. Eradication appeared successful in two, possibly three individuals, but after significant interval (39 weeks in one) S. aureus found of phage type either not isolated before in study, or not found for prolonged period. May reflect inadequacy of conventional sampling methods. S. aureus in throat of nine of twelve nasal carriers. No consistent skin carriers. Seven subjects intermittent nasal carriers. Four probably acquired strain from consistent carriers. Approximately 90% of stored isolates revived for phage on return to UK. Two consistent carriers and one intermittent carrier yielded non-typable strains. Alternative typing method developed. All phage types indistinguishable by polyacrylamide gel electrophoresis (PAGE) of whole cell extracts. Insufficient protein in supernatants for PAGE. Western Blotting of supernatants using normal human plasma as anti-staphylococcal antibody source distinguished between different phage types, but non-typable strains still indistinguishable. Conclusions: 1) Individuals' carrier status stable over many months. Living in proximity to persistent carriers, some individuals never gave positive swab. 2) Throat may be significant carriage site. 3) Topical antibacterial application unlikely to eradicate S. aureus from nose, particularly in persistent carriers. 4) Apparent eradication may represent suppression. 5) Western Blotting of culture supernatants may provide alternative typing method, also information on strains of direct clinical significance.
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Graziano, Talita Signoreti 1988. "Effects of statins in the bacterial viability and on biofilm of Staphylococcus aureus." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289491.
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Orientadores: Karina Cogo Müller, Francisco Carlos GroppoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: As estatinas são um grupo de fármacos que atuam como inibidores competitivos da enzima 3-Hidroxi-3-MetilGlutaril Coenzima-A Redutase (HMG-CoA redutase). Além de atuarem como importantes agentes hipolipemiantes, também apresentam outros efeitos, chamados de pleiotrópicos. Diversos estudos têm explorado um possível efeito protetor das estatinas atuando na redução na morbidade e mortalidade de várias doenças infecciosas. A atividade antimicrobiana das estatinas tem sido reportada por estudos in vivo e in vitro. O objetivo desse estudo foi avaliar os efeitos das estatinas sobre o crescimento e viabilidade de bactérias aeróbias patogênicas, e o efeito da sinvastatina sobre o biofilme de Staphylococcus aureus. Culturas das espécies de Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli e Enterococcus faecalis foram avaliadas na forma planctônica quanto à sensibilidade à atorvastatina, pravastatina e sinvastatina, através do teste de Concentração Inibitória Mínima (CIM). Além disso, diante da atividade apresentada pela sinvastatina contra S. aureus, foi determinada a ação dessa droga sobre a viabilidade celular através dos testes de Time-kill e Efeito pós-antibiótico (EPA). Também foi verificado um possível efeito sinérgico entre a sinvastatina e vancomicina. Por fim, a ação da sinvastatina foi avaliada contra biofilmes de S. aureus. Os valores de CIM da sinvastatina para o microrganismo S. aureus foram: 15,65 µg/ml (ATCC 29213) e 31,25 µg/ml (ATCC 33591, 43300, 14458 e 6538). A sinvastatina apresentou um perfil bacteriostático, e na concentração de 4xCIM seu EPA foi similar ao da vancomicina. Não foi encontrado nenhum tipo de interação entre a associação de sinvastatina e vancomicina. Entretanto, a sinvastatina foi capaz de reduzir a formação do biofilme nas concentrações entre 1/8CIM à 4xCIM. Além disso, na concentração 4xMIC foi capaz de diminuir a viabilidade, biomassa e a produção de polissacarídeos extracelulares e aumentar a produção de polissacarídeos intracelulares de biofilmes maduros de S. aureus. A produção de proteínas pelo biofilme não foi alterada. Em conclusão, os resultados encontrados mostram que a sinvastatina possui um grande potencial a ser explorado, principalmente em relação ao descobrimento de novos antimicrobianos
Abstract: Statins are drugs that competitively inhibit the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA). Besides their important lipid-lowering action, they also are pleiotropic agents. Several studies have explored a possible protective effect of statins to reduce the morbidity and mortality of various infectious diseases. The antimicrobial activity of statins has been reported by in vivo and in vitro studies. The aim of this study was to evaluate the effects of statins on the growth, viability and biofilm formation of pathogenic aerobic bacteria. The Minimum Inhibitory Concentrations (MIC) of atorvastatin, pravastatin and simvastatin against planktonic cells of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis strains were obtained. Since simvastatin showed activity against S. aureus, its effects on cell viability were evaluated in a time-kill and post-antibiotic effect (PAE) assays. A possible synergistic effect between simvastatin and vancomycin was also assessed. In addition, the effect of simvastatin against biofilms of S. aureus was tested. The MIC values of simvastatin for S. aureus were: 15.65 µg/ml (ATCC 29213) and 31.25 µg/ml (ATCC 33591, 43300, 14458 and 6538). Simvastatin showed a bacteriostatic profile, and in a 4x>MIC concentration the PAE was similar to vancomycin. No synergistic effect was found between simvastatin and vancomycin. Simvastatin was able to reduce the formation of biofilms in concentrations ranging from 1/8MIC to 4xMIC. In addition, the 4xMIC was able to decrease the viability, biomass and production of extracellular polysaccharides and increase the production of intracellular polysaccharides on mature biofilm of S. aureus. The protein production on biofilm was not altered in the presence of simvastatin . In conclusion, our results showed that simvastatin has a great potential to be explored, especially in relation to the development new antimicrobial agents
Mestrado
Farmacologia, Anestesiologia e Terapeutica
Mestra em Odontologia
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Wong, Chi-wai Bonnie. "Essentiality of methionine aminopeptidase in staphylococcus aureus." Thesis, Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B31479212.
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Billaud, Anne-Claire. "Studies on inhibition of Staphylococcus aureus by coastal marine bacteria, with emphasis on antibiosis." Thesis, Heriot-Watt University, 1989. http://hdl.handle.net/10399/1970.
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Tegmark, Wisell Karin. "Regulation of virulence gene expression in Staphylococcus aureus /." Stockholm : [Karolinska Univ. Press], 2000. http://diss.kib.ki.se/2000/91-89428-01-3/.
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Melo, Poliana de Castro [UNESP]. "Estudo epidemiológico, genotípico e fenotípico de estirpes de Staphylococcus aureus produtoras de biofilmes isoladas do ambiente de ordenha e de casos de mastite bovina." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/103794.
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000687721.pdf: 1246842 bytes, checksum: dbed8301c1438aca9f1068b68d770d11 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A prevalência da mastite por Staphylococcus aureus em rebanhos leiteiros ocorre devido à sua alta infectividade associada a fatores de virulência que conferem ao microrganismo a capacidade de se instalar no parênquima mamário. Sendo assim o objetivo da presente pesquisa foi avaliar as características fenotípicas, genotípicas e epidemiológicas das estirpes de S. aureus oriundas de leite de vacas com mastite bovina, leite do tanque de expansão, insufladores, mangueiras condutoras de leite, borracha do vácuo, borracha da tampa do tanque de equilíbrio, saída do tanque de equilíbrio, superfície do tanque de expansão e mãos de ordenhadores, em uma propriedade leiteira no município de Indianópolis-MG, no período de Agosto de 2008 a Setembro de 2009. Para tanto foram utilizados os seguintes testes: California Mastitis Test, isolamento microbiológico, provas bioquímicas, extração de DNA, reação em cadeia da polimerase, teste de microplacas, teste do Ágar vermelho congo, microscopia eletrônica de varredura, eletroforese de campo pulsado, teste de sensibilidade aos antimicrobianos, contagem de unidades formadores de colônias, ATP-bioluminescência, eficiência do hipoclorito de sódio e isolamento de pró-fagos e fagos. Os resultados revelaram 440 estirpes de S. aureus com produção de biofilme visualizados nos testes fenotípicos e na microscopia de varredura sendo hla, clfab, agrA e sarA os genes mais prevalentes. Foram também observados a presença de 70 pulsotipos diferentes, sendo o leite de vacas e insufladores os locais com maior quantidade de pulsotipos. Quanto a resistência bacteriana frente aos antimicrobianos foi observada uma maior resistência da Penicilina (90%), Eritromicina (80%)...
The prevalence of Staphylococcus aureus on dairy herds occur due to the high infectivity associated with virulence factors that give the organism the ability to install on the mamary gland, forming microabscesses. Therefore the objective of this study was to evaluate the phenotypic, genotypic and epidemiological strains of S. aureus derived from milk of cows with mastitis, milk tank, foamed milk conductive hoses, vacuum rubber, rubber tank cap balance, leaving the balance tank, the surface of the expansion tank and hands of milk manipulators on a dairy property in the city of Indianapolis-MG in the period August 2008 to September 2009. According to this, the following tests were used: California Mastitis Test, microbiological isolation, biochemical tests, DNA extraction, polymerase chain reaction test, microplate test, Congo red Agar test, scanning electron microscopy, pulsed-field electrophoresis, test antimicrobial susceptibility, counting colony forming units, ATP-bioluminescence, efficiency of sodium hypochlorite and isolation of pro-phages and phages. The results revealed 440 strains of S. aureus to produce biofilm showed in phenotypic tests and scanning electron microscopy and hla, clfAB, agrA and heal the most prevalent genes. It was also observed the presence of 70 different pulsotypes, and the milk of cows and blowers sites with higher amounts of pulsotypes. The bacterial resistance to antimicrobials was observed as increased resistance of penicillin (90%), erythromycin (80%) and clindamycin (74%). When the strains of S. aureus were tested with cell susceptibility to antimicrobials in biofilms it showed the highest efficiency at a concentration of 100mg / L were gentamicin and vancomycin. Concentration of 500mg / L to greater efficiency occurred against vancomycin and gentamicin... (Complete abstract click electronic access below)
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Faria, Rafael César Bolleli. "Resistência a antimicrobianos em Staphylococcus aureus." Universidade Federal de Uberlândia, 2008. https://repositorio.ufu.br/handle/123456789/15785.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorMultiple antibiotic resistant Staphylococcus aureus represent a big problem in the control of hospital infections. Resistance pattern of isolated S. aureus presented in central vascular catheter of patients interned in the Intensive Therapy Center of the School Hospital of the Universidade Federal do Triângulo Mineiro was evaluated by antimicrobial tests, in which it was possible to detect high level of resistance to penicillin (94.7%) and ampicillin (86.8%), only considering the samples that presented resistance, beyond one strain that presented resistance to vancomycin. The oxacillin resistance evaluation was confirmed by PCR with the presence of the gene mecA. The association of the results obtained in the phenotypic test with the presence of the gene mecA, considered the reference method, was confirmed through the Table of Contingency and the Test of Χ2 with Yates correction. In 49 isolates evaluated, 23 were resistant to oxacillin, being possible to detect the mecA gene in 21 samples. The test of molecular screening by RAPD allowed the separation of the phenotypic groups in two different grouping patterns, the ones that presented resistance to antimicrobials and the sensible ones, with a dissimilarity of 73,3%. There is a higher genetic similarity between groups that present the same type of resistance, thus confirming the phenotypic analyses. Molecular markers for detection of resistance to oxacillin, like the gene mecA, were more sensitive than the phenotypic markers.
Staphylococcus aureus resistentes a múltiplos antibióticos representam um grande problema no controle das infecções hospitalares. O perfil de resistência a antimicrobianos de isolados de S. aureus presentes em cateteres vasculares central de pacientes internados em leitos do centro de terapia intensiva do Hospital Escola da Universidade Federal do Triângulo Mineiro foi avaliado por meio de testes antimicrobianos, pelos quais foi possível detectar um elevado nível de resistência à penicilina (94,7%) e ampicilina (86,8%), considerando-se somente as amostras que possuíam resistência, além de uma cepa resistente à vancomicina. A avaliação da resistência à oxacilina foi confirmada por PCR através da presença do gene mecA. A associação dos resultados obtidos no teste fenotípico com a presença do gene mecA, considerado um método de referência, foi confirmada através da Tabela de Contingência e do Teste de Χ2 com correção de Yates. Em 49 amostras avaliadas, 23 apresentaram resistência à oxacilina, sendo possível detectar a presença do gene de resistência mecA em 21 amostras. O teste de tipagem molecular por RAPD permitiu a separação dos grupos fenotípicos em dois padrões diferentes de agrupamento, os que possuíam resistência e os sensíveis aos antimicrobianos, com uma dissimilaridade de 73,3%. Há maior similaridade genética entre grupos que apresentam o mesmo tipo de resistência, confirmando assim as análises fenotípicas. Marcadores moleculares para detecção de resistência à oxacilina, como o gene mecA, foram mais sensíveis que os marcadores fenotípicos.
Mestre em Genética e Bioquímica
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Bjertsjö, Rennermalm Anna. "Staphylococcal cell wall associated proteins : characteristics and host interactions /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-542-9/.
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Colque-Navarro, Patricia. "Serum antibodies against Staphylococcus aureus antigens in healthy individuals and patients with invasive infections." Stockholm, 2010. http://diss.kib.ki.se/2010/978-91-7409-841-9/.
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Wiltshire, Michael David. "The identification of genes important to the growth of Staphylococcus aureus in in vitro models mimicking infection." Thesis, University of Sheffield, 2001. http://etheses.whiterose.ac.uk/14812/.
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Staphylococcus aureus is a major pathogen, which causes a wide range of infections. Despite its obvious clinical importance, little is known about the mechanisms of pathogenesis. An in vitro model mimicking infection was developed in order to identify putative virulence determinants. The model involves the growth of S. aureus in serum under microaerobic conditions. All known virulence factors tested were shown not to be required for growth, or preferentially expressed, in serum. Tn917 transposon libraries of S. aureus were screened to identify genes preferentially expressed in serum, compared to a nutrient-rich growth medium. 73 clones were identified and the transposon insertion site was characterised for 23 of these clones. Analysis of sequence flanking the transposon insertion revealed the identity of the mutated loci. 10 out of 23 sequenced clones, contained transposons inserted within genes involved in the biosynthesis of the aspartate family of amino acids (lysine. threonine, methionine and isoleucine). These were: the two common pathway enzymes; aspartokinase (lysC) , and aspartate semi aldehyde dehydrogenase (asd) , along with; dihydrodipicolinate dehydrogenase (dapA), and cystathionine y-synthase (yjcf) , involved in the biosynthesis oflysine and methionine respectively. Analysis of methionine biosynthesis indicated that S. aureus possesses only a single pathway, which proceeds via cystathionine. Several genes encoding methionine biosynthetic enzymes were found clustered on the S. aureus chromosome. The genes lyse, asd and dapA were found to be encoded by the first three genes of an eight gene operon, which also contains three other genes involved in lysine biosynthesis. This operon named the dap operon, is the major lysine biosynthetic operon of S. aureus. lysC, asd and dapA were all found to be repressed at the transcriptional level primarily by lysine, although factors other than the availability of lysine may be responsible for the regulation of lysine biosynthetic gene expression in serum. lysC, asd and dapA were all found to be expressed in vivo, in a murine pyelonephritis model using both RT-PCR and TaqMan techniques. However, these genes were not found to be important in three murine pathogenicity models. Finally, in addition to the development of a model mimicking infection, and the identification of genes with a potentially important role in vivo, this thesis has enhanced our understanding of both methionine and lysine biosynthesis in S. aureus.
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Weidman, Chelsea. "Increasing Staphylococcus Aureus Antibiotic Susceptibility Through Membrane Charge Manipulation Using Peptides and Small Molecules." Thesis, Boston College, 2017. http://hdl.handle.net/2345/bc-ir:107694.
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Thesis advisor: Jianmin GaoWith the rapid evolution of antibiotic resistance, the need for more effective antibiotics is imminent. Bacterial membranes are an appealing target due to their accessibility and relatively conserved structures. Membrane targeting antibiotics, especially cationic antimicrobial peptides (CAMPs) such as host defense peptides, have been increasingly explored as novel antibiotics and tunable innate antimicrobials. The latter could be achieved by treatment with an antibiotic adjuvant: a compound that would increase the potency of host CAMPs without killing the bacteria on its own. Boosting the host’s own immune system with an adjuvant is beneficial over using antibiotics and would theoretically avoid triggering bacterial resistance. One mechanism of bacterial resistance is increasing the cationic charge of the membrane. As CAMPs are electrostatically attracted to anionic bacterial membranes, making the membrane more cationic decreases that attraction, rendering CAMPs less effective. To target this resistance mechanism chemically, two antibiotic adjuvant strategies were explored as co-treatments with various CAMPs: membrane targeting peptides used to bind and block surface amines, and small molecules used to either acetylate surface amines or convert a cationic membrane phospholipid to an anionic phospholipid. Co-treatment of the Staphylococcus aureus (S. aureus) membrane targeting peptide KAM-CT and various CAMPs increased S. aureus susceptibility to those CAMPs. Bacterial surface acetylation using sulfo-NHS-acetate followed by CAMP treatment caused up to 10 times increased CAMP potency. Hydrazine and hydroxylamine were shown to cleave the lysine moiety from the lysyl-phosphatidylglycerol (Lys-PG) phospholipid to generate phosphatidylglycerol (PG) in liposome models. S. aureus was treated with a hydroxylamine-CAMP conjugate, but it showed decreased antibiotic activity compared to the CAMP alone. To better understand what was happening in the bacteria, a novel Lys-PG quantification protocol was created by fluorophore labeling Lys-PG and quantifying the labeled Lys-PG via normal phase high-performance liquid chromatography (NP-HPLC). Cyclic peptides, such as KAM-CT, represent complex yet synthetically attainable moieties that could be used as novel antibiotics adjuvants. Expanding the repertoire of reversible covalent chemistries, especially those applied to peptide cyclization, is desirable due to the high potency and selectivity of such interactions. Herein, we also describe a novel reversible covalent chemistry between 2-formylphenylboronic acid (FPBA) and 2,3-diaminopropionic acid (Dap): the imidazolidino boronate (IzB) conjugate. It was found to be potent (Kd = 100 μM) and quickly reversible (t1 = ~6 sec) under physiological conditions. IzB formation was successfully employed as a peptide cyclization strategy as there was little interference from biologically relevant small molecules, except cysteine. Cysteine interference was utilized to create “smart” peptides that can linearize upon increasing cysteine concentrations via thiazolidino boronate (TzB) formation with the FPBA moiety in the peptide. Such “smart” peptides could be used as pH-responsive peptides or cysteine sensors able to report on the cysteine concentration in complex media
Thesis (MS) — Boston College, 2017
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Casarin, Letícia Sopeña. "Sobrevivência de Escherichia coli,Staphylococcus aureus e Salmonella Enteritidis durante o armazenamento de hambúrguer de frango." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/5369.
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Com o objetivo de avaliar a sobrevivência ao congelamento de microrganismos potencialmente patogênicos, hambúrgueres de frango foram contaminados com Escherichia coli (ECHC), Staphylococcus aureus (SAFH) e Salmonella Enteritidis (SE86) e armazenados a -18ºC. Os mesmos microrganismos e ainda E. coli ATCC 25972, S. aureus ATCC 25923, and S. Enteritidis ATCC 13076 também foram inoculados em água peptonada 0,1% e congelados a -18ºC, a fim de avaliar um possível efeito protetor dos componentes do hambúrguer sobre os microrganismos. A quantificação dos microrganismos foi realizada nos intervalos de 0, 1, 2, 3, 4, 7, 14, 21 e 28 dias de congelamento. Com o propósito de estudar as alterações nos ácidos graxos das células microbianas expostas ao congelamento, foram extraídos os ácidos graxos de cada bactéria, congelada e não congelada, e estes foram analisados por cromatografia gasosa. Os resultados demonstraram que, de modo geral, houve uma redução média de menos de 1 unidade logarítmica (log10) no número de células artificialmente inoculadas em hambúrgueres de frango. As reduções obtidas para cada microrganismo em água peptonada 0,1% foram significativamente (P0,05) maiores do que as reduções observadas em hambúrguer de frango, sugerindo a existência de um efeito crioprotetor dos componentes do hambúrguer. Em todos os experimentos, as reduções mais expressivas foram observadas nas primeiras semanas de congelamento. Ocorreram alterações expressivas na composição de ácidos graxos de S. aureus (SAFH) e S. aureus ATCC 25923, o que pode indicar que estes microrganismos alteraram a composição dos seus ácidos graxos como resposta ao estresse causado pelo congelamento.
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Souza, Rodrigo Malzoni de. "Capacidade de resistência à fagocitose e atividade bactericida de neutrófilos por distintas cepas de estafilococos associadas à mastite em vacas primíparas e multíparas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/10/10136/tde-09042018-094125/.
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O grupo de estafilococos não-aureus (SNA), frequentemente isolados de quartos mamários com mastite subclínica, ápice do teto e ambiente, possue variabilidade ecológica que desafia a compreensão da patogenia a estes atribuída. Os fatores espécie-específicos associados à essa infecção ainda não foram identificados e a susceptibilidade difere entre vacas e quartos e promove diferentes perfis de infecção. Com o objetivo de avaliar a resistência à fagocitose e atividade microbicida, comparou-se a viabilidade, a produção intracelular de espécies reativas de oxigênio (ERO) e a fagocitose de neutrófilos sanguíneos de vacas primíparas e multíparas frente a distintos isolados viáveis de estafilococos. Utilizou-se doze vacas sadias (seis primíparas e seis multíparas) em terço médio de lactação e SO isolados viáveis de estafilococos (38 SNA e 12 Staphylococcus aureus) de diferentes nichos ecológicos. A viabilidade de neutrófilos (P = 0,55), produção de ERO (P = 0,12) e atividade funcional dos fagócitos (P = 0,33) foram semelhantes entre as primíparas e multíparas testadas . Contudo, foram observadas diferenças (P ≤0,05) entre os distintos grupos de espécies e estirpes de estafilococos quanto ao estímulo da produção intracelular de ERO pelos neutrófilos e à fagocitose. S. chromogenes de origens distintas, ápice do teto (P = 0,01), infecção intramamária transiente (P < 0,01) e infecção intramamárias persistente (P < 0,01) estimularam mais a produção de ERO pelos neutrófilos do que as outras espécies. Todos isolados foram fagocitados pelos neutrófilos, mas S. chromogenes resistiram mais eficientemente que as outras espécies de SNA, principalmente, S. chromogenes isolados do ápice do teto (P < 0,01). S. haemolyticus isolados do ápice do teta (P = 0,02) e infecção intramamária transiente (P < 0,01), assim como, S. fleurettii (P < 0,01), foram substancialmente fagocitados do mesmo modo que S. aureus isolado de suabe nasa\\ (P = 0,03). Mais evidente do que possíveis variações entre as respostas mamárias de primíparas e multíparas é a variação entre os SNA. Quanto mais adaptado à mama, maior resistência à fagocitose.The group of non-aureus staphylococci (NAS), often isolated from mammary quarters with subclinical mastitis, teat apex and environment, has ecological variability that challenges the understanding of the pathogenesis attributed to them. The species-specific factors associated with this infection have not yet been identified and the susceptibility differs between cows and quarters and promotes different infection profiles. In order to evaluate the resistance to phagocytosis and I or microbicidal activity of these pathogens, the viability , intracellular production of reactive oxygen species (ROS) and blood neutrophil phagocytosis of primiparous and multiparous cows were compared to different viable isolates of staphylococci. Twelve healthy cows (six primiparous and six multiparous) were used in the middle third of lactation and 50 viable isolates of staphylococci (38 SNA and 12 Staphylococcus aureus) from different ecological niches. Neutrophil viability (P = 0.55), ROS production (P = 0.12) and phagocyte functional activity (P = 0.33) were similar among the primiparous and multiparous groups tested. However, differences (P <0.05) between the different groups of species and strains of staphylococci were observed for the stimulation of intracellular ROS production by neutrophils and phagocytosis. S. chromogenes of different origins, ceiling apex (P =0.01), transient intramammary infection (P <0.01) and persistent intramammary infection (P <0 .01) further stimulated the production of ROS by neutrophils than species. All isolates were phagocytosed by neutrophils, but S. chromogenes resisted more efficiently than the other SNA species, especially S. chromogenes isolated from the apex of the ceiling (P <0.01). S. haemolyticus isolated from apex to ceiling (P =0.02) and transient (P <0.01) intramammary infection, as well as S. fleurettii (P <0.01), were substantially phagocytosed in the same manner as S. aureus isolated from nasal swab (P = 0.03). More evident than possible variations between mammary responses of primiparous and multiparous is the variation between ANS. The more adapted to the breast, the greater resistance to phagocytosis.
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Cechinel, Angélica Bauer. "Bacteremias por Staphylococcus aureus meticilina resistentes em um hospital terciário : análise clínica, microbiológica e molecular." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/131211.
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Introdução: Staphylococcus aureus é um patógeno que causa uma variedade de infecções nosocomiais e comunitárias. Bacteremia por Staphylococcus aureus meticilina resistente (MRSA) está associada com uma elevada morbidade e mortalidade. Alguns autores consideram uma maior taxa de mortalidade em bacteremia por MRSA em comparação aos observados em bacteremia causada por Staphylococcus aureus sensível a meticilina. O uso da vancomicina no tratamento de infecções por MRSA tem estado sobre crescente vigilância nos últimos anos, já que existe uma grande preocupação sobre a redução de sua eficácia no tratamento de pacientes com bacteremia por MRSA. Estudos sugerem que a vancomicina tem atividade reduzida contra infecções por MRSA quando os valores da concentração inibitória mínima (CIM) se aproximam do valor máximo considerável como susceptível. O locus (acessory gene regulator) regula a expressão de vários genes de virulência, de aderência e produção de biofilme, e pode estar envolvido com a diminuição da sensibilidade a vancomicina. O staphylococcal cassette chromosome (SCCmec) carreia o gene mecA que caracteriza o fenótipo clássico de MRSA e confere resistência aos antibióticos β-lactâmicos. Objetivos: Avaliar as CIMs dos antibióticos: vancomicina, por microdiluição em caldo, e daptomicina, linezolida, tigeciclina e quinopristina/dalfopristina e teicoplanina pela metodologia de Etest®; caracterizar o polimorfismo do locus agr e os tipos de SCCmec de isolados de MRSA de pacientes internados em um hospital, terciário e acadêmico, no sul do Brasil. Métodos: Estudo retrospectivo de coorte no qual foram avaliados todos os episódios de bacteremia causada por MRSA nos Centros de Terapia Intensiva (CTIs) durante o período de junho de 2009 a dezembro de 2011. A detecção dos grupos agr (agr tipo I, II, III e IV) e SCCmec (SCCmec I, II, III, IV e V) foi realizada a partir da técnica da reação em cadeia da polimerase (PCR). Resultados: Foram incluídos no total 21 pacientes. Os isolados de MRSA testados se apresentaram sensíveis a todos os antibióticos testados. O locus agr foi determinado em todos os isolados, sendo que onze pertencem ao grupo agr I (52,4%) e dez ao grupo agr II (27,6%). Já a caracterização dos tipos de SCCmec, não foi possível para onze isolados; para o restante, foi encontrado dois isolados SCCmec tipo I, cinco SCCmec tipo III e três SCCmec tipo IV. Conclusão: Apesar do pequeno número de pacientes e da necessidade de maiores estudos em nosso meio, nossos resultados sugerem que a vancomicina continua a ser a primeira opção de escolha para o tratamento de infecções por MRSA, como recomendado pela Infectious Diseases Society of America. No entanto, a publicação de uma série de estudos sugerindo a susceptibilidade reduzida à vancomicina, mesmo com CIMs próximas ou no ponte de corte, a terapia com vancomicina não seria recomendada a estes pacientes, sendo necessário a avaliação de um novo esquema terapêutico.Background: Staphylococcus aureus is a versatile pathogen that cause a variety of nosocomial and community infections. Bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA) is associated with high morbidity and mortality. Some authors consider a higher rate of mortality in MRSA bacteremia compared to those observed in bacteremia caused by methicillin-sensitive Staphylococcus aureus. The use of vancomycin to treat infection due to MRSA has been under increased vigilance in recent years, since there is great concern about reducing their effectiveness in treating patients with MRSA bacteremia. Studies suggest that reduced activity against vancomycin has MRSA when the values of the minimum inhibitory concentration (MIC) approach the upper end of the range of susceptibility. The agr locus (acessory regulator gene) and regulates the expression of several virulence genes, adherence and biofilm production and can be involved in reduced sensitivity to vancomycin. The staphylococcal cassette chromosome (SCCmec) carries the mecA gene that characterizes the classic phenotype of MRSA and confers resistance to β-lactam antibiotics. Objectives: Evaluate MICs of antibiotics: vancomycin, by broth microdilution, and daptomycin, linezolid, tigecycline and quinopristina / dalfopristin and teicoplanin by Etest® methodology; characterize the polymorphism of the agr locus and SCCmec types of MRSA isolates from patients in a hospital, tertiary and academic, in southern Brazil. Methods: A retrospective cohort study which evaluated all episodes of bacteremia caused by MRSA in intensive care units (ICUs) during the period June 2009 to December 2011. The detection of agr groups (agr type I, II, III and IV) and SCCmec (SCCmec I, II, III, IV and V) were performed using the technique of polymerase chain reaction (PCR). Results: We included a total twenty one patients. The MRSA isolates tested were susceptible to all antibiotics tested. The agr locus was determined in all isolates, eleven belong to agr group I (52.4%) and ten to agr group II (27.6%). Already characterization of SCCmec types, it was not possible to eleven isolates; for the remaining two isolates found was SCCmec type I, five SCCmec type III and three SCCmec type IV. Conclusions: Despite the small number of patients and the need for further studies in this area, our results suggest that vancomycin remains the first choice option for the treatment of MRSA infections, as recommended by the Infectious Diseases Society of America. However, the publication of a series of studies suggesting reduced susceptibility to vancomycin, even with MICs near or on cut off, with vancomycin therapy would not be recommended for these patients, the evaluation of a new regimen is necessary.
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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.
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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
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Alvarez, Vega Luis Guillermo. "Detección de Staphylococcus pseudintermedius y Staphylococcus aureus aislados de piodermias caninas mediante PCR-RFLP." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2019. https://hdl.handle.net/20.500.12672/11838.
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A nivel mundial la piodermia es una de las enfermedades de la piel más diagnosticada en
caninos. Entre los agentes involucrados se encontraba Staphylococcus intermedius, el que
se creía el principal agente de las piodermias caninas; sin embargo, en el año 2005 fue
reclasificado en 3 especies: S. intermedius, S. pseudintermedius y S. delphini.
Posteriormente, estudios en diferentes países reportaron que el Staphylococcus
pseudintermedius es en realidad el agente bacteriano más frecuentemente aislado en
piodermias, seguidamente surgieron los primeros reportes de aislados resistentes a
meticilina. Por otro lado, Staphylococcus aureus, patógeno importante en medicina
humana, se aísla con más frecuencia en muestras de piodermias caninas, siendo estos
potenciales reservorios para reinfecciones en humanos de cepas resistentes a antibióticos.
Por ello, este estudio buscó determinar la presencia S. pseudintermedius y S. aureus en
141 aislados de Staphylococcus sp. provenientes de casos de piodermia canina del periodo
2016 - 2018. El ADN de los 141 aislados fue extraído y analizado mediante PCR-RFLP,
el cual consistió en la amplificación del gen pta y la digestión con la enzima MboI.
Obteniendo que los aislados de Staphylococcus sp. fueron identificados como
Staphylococcus pseudintermedius en un 87.9%, 12.1% como otros Staphylococcus sp. y
no se detectó Staphylococcus aureus. Concluyéndose que el Staphylococcus más
frecuentemente involucrado en piodermias caninas es el Staphylococcus
pseudintermedius; sin embargo, no se debe omitir el rol potencial que puede cumplir
Staphylococcus aureus como patógeno en caninos.Universidad Nacional Mayor de San Marcos (Lima). Vicerrectorado de Investigación y Posgrado
Tesis
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Shannon, Oonagh. "Biological effects of extracellular fibrinogen binding protein (Efb) in Staphylococcus aureus infection /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-275-6/.
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Melo, Poliana de Castro. "Estudo epidemiológico, genotípico e fenotípico de estirpes de Staphylococcus aureus produtoras de biofilmes isoladas do ambiente de ordenha e de casos de mastite bovina /." Jaboticabal : [s.n.], 2011. http://hdl.handle.net/11449/103794.
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Orientador: Antonio Nader FilhoCoorientador: Paulo Pinto Gontijo Filho
Banca: Antonio Sérgio Ferraudo
Banca: Luiz Augusto do Amaral
Banca: Denise Von Doliger de Brito
Banca: Domingas do Rosário Veríssimo Jacinto Tavares de Oliveira
Resumo: A prevalência da mastite por Staphylococcus aureus em rebanhos leiteiros ocorre devido à sua alta infectividade associada a fatores de virulência que conferem ao microrganismo a capacidade de se instalar no parênquima mamário. Sendo assim o objetivo da presente pesquisa foi avaliar as características fenotípicas, genotípicas e epidemiológicas das estirpes de S. aureus oriundas de leite de vacas com mastite bovina, leite do tanque de expansão, insufladores, mangueiras condutoras de leite, borracha do vácuo, borracha da tampa do tanque de equilíbrio, saída do tanque de equilíbrio, superfície do tanque de expansão e mãos de ordenhadores, em uma propriedade leiteira no município de Indianópolis-MG, no período de Agosto de 2008 a Setembro de 2009. Para tanto foram utilizados os seguintes testes: California Mastitis Test, isolamento microbiológico, provas bioquímicas, extração de DNA, reação em cadeia da polimerase, teste de microplacas, teste do Ágar vermelho congo, microscopia eletrônica de varredura, eletroforese de campo pulsado, teste de sensibilidade aos antimicrobianos, contagem de unidades formadores de colônias, ATP-bioluminescência, eficiência do hipoclorito de sódio e isolamento de pró-fagos e fagos. Os resultados revelaram 440 estirpes de S. aureus com produção de biofilme visualizados nos testes fenotípicos e na microscopia de varredura sendo hla, clfab, agrA e sarA os genes mais prevalentes. Foram também observados a presença de 70 pulsotipos diferentes, sendo o leite de vacas e insufladores os locais com maior quantidade de pulsotipos. Quanto a resistência bacteriana frente aos antimicrobianos foi observada uma maior resistência da Penicilina (90%), Eritromicina (80%)... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The prevalence of Staphylococcus aureus on dairy herds occur due to the high infectivity associated with virulence factors that give the organism the ability to install on the mamary gland, forming microabscesses. Therefore the objective of this study was to evaluate the phenotypic, genotypic and epidemiological strains of S. aureus derived from milk of cows with mastitis, milk tank, foamed milk conductive hoses, vacuum rubber, rubber tank cap balance, leaving the balance tank, the surface of the expansion tank and hands of milk manipulators on a dairy property in the city of Indianapolis-MG in the period August 2008 to September 2009. According to this, the following tests were used: California Mastitis Test, microbiological isolation, biochemical tests, DNA extraction, polymerase chain reaction test, microplate test, Congo red Agar test, scanning electron microscopy, pulsed-field electrophoresis, test antimicrobial susceptibility, counting colony forming units, ATP-bioluminescence, efficiency of sodium hypochlorite and isolation of pro-phages and phages. The results revealed 440 strains of S. aureus to produce biofilm showed in phenotypic tests and scanning electron microscopy and hla, clfAB, agrA and heal the most prevalent genes. It was also observed the presence of 70 different pulsotypes, and the milk of cows and blowers sites with higher amounts of pulsotypes. The bacterial resistance to antimicrobials was observed as increased resistance of penicillin (90%), erythromycin (80%) and clindamycin (74%). When the strains of S. aureus were tested with cell susceptibility to antimicrobials in biofilms it showed the highest efficiency at a concentration of 100mg / L were gentamicin and vancomycin. Concentration of 500mg / L to greater efficiency occurred against vancomycin and gentamicin... (Complete abstract click electronic access below)
Doutor
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Haggar, Axana. "Interaction between Extracellular adherence protein (Eap) from Staphylococcus aureus and the human host." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-496-1/.
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Holdren, Cortlyn. "Deciphering the Mechanisms of Alcaligenes faecalis’ Inhibition of Staphylococcus aureus and Synergism with Antibiotics." Digital Commons @ East Tennessee State University, 2021. https://dc.etsu.edu/honors/628.
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Staphylococcus aureus has developed resistance to several antibiotics including vancomycin, which is often used as a “last resort” treatment. There is an ever-increasing need to develop novel antimicrobial treatments to combat S. aureus and other drug resistant bacteria. Microorganisms are most often found in polymicrobial communities where they either exhibit synergistic or antagonistic relationships. Competition between microorganisms can lead to the discovery of new antimicrobial targets as the specific mechanisms of resistance are elucidated. In addition, synergistic treatments are being evaluated for their combined effect and potential to decrease the concentration of drugs needed, and thus the side effects also. Alcaligenes faecalis is a microorganism that our lab has previously shown to inhibit S. aureus and other various bacterial species. In this study, we found that A. faecalis reduces the planktonic growth of S. aureus by 94.5% and biofilm growth by 76.6%. A. faecalis also has a synergistic effect when paired with bacitracin to reduce the planktonic growth by 99.9% and biofilm growth by 99.7%. Transposon mutagenesis was successfully performed on A. faecalis, and loss of function mutations were attained. Two mutants were no longer able to inhibit the growth of Staphylococcus aureus, Candida albicans, or Bacillus megaterium. Further analysis and genomic sequencing of these mutants is needed to determine the gene(s) that were interrupted and the mechanism of A. faecalis’ antimicrobial activity. The findings of this study may aid in the identification of new therapeutic targets for novel S. aureus treatments.
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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.
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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
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McDanel, Jennifer Sue. "The prevention, treatment, and outcomes of Staphylococcus aureus infections." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/5023.
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Staphylococcus aureus causes an assortment of infections that range from mild skin infections to bacteremia or necrotizing pneumonia. Patients with S. aureus infections may suffer poor outcomes such as extended hospital stay and death. The goal of this study was to improve outcomes of patients with S. aureus infections by examining microbial characteristics of S. aureus associated with poor clinical outcomes, and comparative effectiveness of S. aureus treatment options for patients with S. aureus infections. Additionally, methods to prevent S. aureus infections among hospitalized patients were assessed.
We performed a two-hospital retrospective cohort study to identify microbial characteristics, patient characteristics, or antimicrobial treatments that were predictors of mortality or length of stay among patients with methicillin-resistant S. aureus (MRSA) pneumonia. We found increased age (> 54 years) (hazard ratio [HR]: 4.49; 95% confidence interval [CI]: 1.64-12.33), intensive care unit (ICU) admission (HR: 5.25; CI: 1.52-18.21), and having a hospital-onset pneumonia (HR: 0.32; CI: 0.13-0.75) were associated with mortality while admission to the ICU (odds ratio [OR]: 7.34; CI: 3.58-15.04), increased age (> 54 years) (OR: 2.27; CI: 1.19-4.35), having a hospital-onset pneumonia (OR: 3.60; CI: 1.26-10.28), and receiving vancomycin (OR: 10.85; CI: 3.68-32.00) were predictors of increased length of stay. None of the tested microbial characteristics were associated with poor outcomes.
We also completed a multicenter retrospective cohort study to compare the effect of beta-lactams versus vancomycin (both empiric and definitive therapy) on mortality for patients with methicillin-susceptible S. aureus (MSSA) bacteremia who were admitted to Veteran Affairs Medical Centers. We found an increased hazard of mortality for patients who received empiric treatment with a beta-lactam compared with vancomycin (HR: 1.19, 95% CI: 1.00-1.42). However, we observed a protective effect among patients who received definitive treatment with a beta-lactam compared with vancomycin (HR: 0.66; CI: 0.50-0.87).
In 2007, 2009-2011, we administered surveys that focused on the implementation of the Institute for Healthcare Improvement's (IHI) MRSA bundle to reduce hospital-onset MRSA infections to infection preventionsts who worked in Iowa hospitals. By the end of the study period, most hospitals implemented a hand hygiene program (range: 87%-94%), placed infected (range: 97%-100%) or colonized patients (range: 77%-92%) on contact precautions, performed active surveillance culturing to identify colonized patients, and monitored the effectiveness of environmental cleaning (range: 23%-71%; P < 0.001).
To improve patient outcomes, physicians should provide beta-lactams for definitive treatment of patients with MSSA bacteremia. However, the most effective method to improve outcomes is to prevent S. aureus infections from occurring. This study provides benchmark data that infection prevention staff in rural hospitals throughout the U.S. can use to compare their practices with Iowa hospitals.
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Rizek, Camila Fonseca. "Pesquisa de genes de resistência a antimicrobianos beta-lactâmicos e de enterotoxina em cepas de Staphylococcus aureus presentes em amostras de alimentos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/6/6135/tde-28102010-171305/.
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Introdução: Staphylococcus aureus são microrganismos causadores de diversos tipos de doenças. Existem dois grandes agravantes a sua presença: a produção de toxinas e a resistência a antimicrobianos. S. aureus produzem enterotoxinas termolábeis que, quando presentes nos alimentos, podem levar a uma toxinfecção a quem o consumir. Esta espécie também é conhecida por facilmente responder adaptativamente ao uso de drogas tornandose cada vez mais difícil controlá-la. Um dos maiores responsáveis por esta preocupação são os MRSA (methicillin-resistant Staphylococcus aureus), resistentes a beta-lactâmicos através da produção de uma proteína diferenciada de parede codificada pelo gene mecA. A presença deste patógeno resistente fora do ambiente hospitalar é registrada há alguns anos e pouco a pouco vem se descobrindo que a via alimentar pode ser um meio deste gene se disseminar. Objetivos: procurar pelo gene mecA e o codificador da enterotoxina em Staphylococcus aureus de amostras alimentares para discutir a presença do gene de resistência em uma nova via de transmissão e a validade de apenas se fiscalizar a presença apenas de Staphylococcus coagulase positivo em produtos alimentares como forma de manter o alimento seguro contra toxinfecções. Métodos: Cinquenta e sete amostras de S. aureus provenientes de amostras de quatro tipos de fontes alimentares foram testadas por PCR com primer específico para o gene mecA e para o gene codificador da enterotoxina. Resultados: Destas, cinco (8,8 por cento do total) amostras apresentaram o gene de resistência e onze (19,2 por cento do total) continham o gene codificador da enterotoxina termolábil. Conclusão: A presença do gene de enterotoxina em produtos prontos para consumo e peixe cru de feira é uma realidade, assim como o debate sobre qual a melhor forma de se legislar sobre o assunto que deve ser mantido e melhor avaliado. Já no caso do gene de resistência, evidenciou-se que a via alimentar é sim local de circulação do gene de resistência. Também é a primeira vez que se notifica o gene mecA em alimentos prontos para consumo no Brasil e América LatinaIntroduction: Staphylococcus aureus are a bacterium that causes various types of diseases. There are two major aggravating to its presence: the toxins production and antimicrobial resistance. S. aureus produce heat-labile enterotoxina that, when present in food, can lead to poisoning of those who consume. This specie is also known to easily respond adaptively to drug use becoming increasingly difficult to control it. One of the main reasons for this concern are MRSA (methicillin-resistant Staphylococcus aureus) which are resistant to betalactams drugs through a differentiated wall protein production encoded by the mecA gene. The presence of this resistant pathogen outside hospitals has been recorded a few years ago and gradually comes to discover that the food chain can be a way for the gene spread. Objectives: Search for the mecA gene and the enterotoxins encoded gene in Staphylococcus aureus from food samples to discuss the presence of the resistance gene in a new transmission route and the validity of only review the presence of Staphylococcus coagulase positive in food product as a way to keep insurance against food poisoning. Methods: Fifty-seven samples of S. aureus from five different sources of food samples were tested by PCR with specific primer for the mecA gene and the enterotoxins gene. Results: Of these, five (8,8 per cent of total) samples showed the resistance gene and eleven (19,2 per cent of total) contained the gene encoding the heat-labile enterotoxin. Conclusion: The presence of enterotoxin encoded gene in food products ready for consumption and raw fish is a fact and a debate about how best to legislate should be maintained and better evaluated. In the case of the resistance gene, the food chain is really a way where this gene can spread. It is also the first time the mecA gene from food ready for consumption is reported in Brazil and Latin America
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Cirino, Isis Caroline da Silva. "Modulação da resistência a drogas por óleos essenciais em linhagens de Staphylococcus aureus." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/3665.
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Bacterial resistance to drugs can happen due to different mechanisms. Among these, efflux bombs highlights and these structures are integrant part of membran cell. The increasing incidence of resistant bacteria has undermined the therapeutic value of available antibacterials, creating the necessity, increasingly, the search for alternatives that can reverse or decrease the resistance, as the search for inhibitors of resistance mechanisms. In order to resolve this problem, products from plants (extracts, essencial oils and phytoconstituents) rise as rich research source on drug resistance modulators , that is, drugs that increase antibiotics activity or even revert bacterial resistance. In this work, we investigated how modifiers of antibiotic activity act in Staphylococcus aureus strains that are efflux bombs carriers. The essencial oils used were extracted from Rosmarinus officinalis L., Illicium verum Hook., Cananga odorata, Eucalytus globulus, Pelargonium graveolens , Citrus paradisi, Cymbopogon flexuosus, Melaleuca alternifolia, Mentha Spicata, Origanum vulgare, Cymbopogon Martini, and their major constituents used were 1,8-cineol, Anetol, Trans-Caryophyllene, Citronelol, Limoneno, Citral, Terpenen-4-ol, L-carvone, Carvacrol and Geraniol. Our results show that the natural products evaluated, in general, present significant antibacterial activity, and probably they operate as modifiers of antibiotic activity, strains through reduction of CIM of tested antibiotics (tetracycline, erythromycin and norfloxacin) from 2 to16 fold. The results show that natural products from plants are in fact potential antibiotics adjuvants.
A resistência bacteriana a drogas pode ser ocasionada por diferentes mecanismos. Dentre esses, podemos destacar as chamadas bombas de efluxo as quais são partes integrantes da membrana plasmática. A crescente incidência de bactérias resistentes tem minado o valor terapêutico dos antibacterianos existentes, criando a necessidade, cada vez maior, da busca por alternativas capazes de reverter ou diminuir a resistência. Na tentativa de encontrar uma solução para esse problema, os produtos de origem vegetal (extratos, óleos essenciais e fitoconstituintes) surgem como uma rica fonte de pesquisa na busca de potenciais moduladores da resistência à droga , ou seja, drogas que aumentam a atividade de certos antibióticos ou mesmo revertem a resistência bacteriana. Neste trabalho, avaliamos o efeito modificador da atividade antibiótica em linhagens de Staphylococcus aureus - portadoras das bombas de efluxo - o óleo essencial de Rosmarinus officinalis L., Illicium verum Hook., Cananga odorata, Eucalytus globulus, Pelargonium graveolens , Citrus paradisi, Cymbopogon flexuosus, Melaleuca alternifólia, Mentha Spicata, Origanum vulgare, Cymbopogon Martini e seus constituintes majoritários, 1,8 cineol, Anetol, Trans-Caryophyllene, Citronelol, Limoneno, Citral, Terpinen-4-ol, L-carvone, Carvacrol e Geraniol. Como resultado, observou-se que os produtos naturais avaliados, de maneira geral, apresentaram significativa atividade antibacteriana e podem atuar como modificadores da atividade antibiótica ao reduzirem a CIM dos antibióticos testados (tetraciclina, eritromicina e norfloxacina) de 2 a 16 vezes. Os resultados indicam que produtos naturais de origem vegetal são, de fato, potenciais adjuvantes de antibióticos.
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Haileselassie, Yeneneh. "THE INFLUENCE OF LACTOBACILLI AND STAPHYLOCOCCUS AUREUS ON IMMUNE RESPONSIVENESS IN VITRO." Licentiate thesis, Stockholms universitet, Institutionen för molekylär biovetenskap, Wenner-Grens institut, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-94326.
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Alteration of gut microbiota has been associated with development of immune mediated diseases, such as allergy. In part, this could be due to the influence of microbes in shaping the immune response. In paper I, we investigated the association of early-life gut colonization with bacteria, and numbers of IL-4, IL-10 and IFN-γ producing cells at two years of age in response to PBMC stimulation with phytohemagglutinin (PHA) in vitro. Early Staphylococcus (S) aureus colonization was directly proportional to increased numbers of IL-4 and IL-10 secreting cells, while early co-colonization with lactobacilli and S. aureus associated with a decrease in IL-4, IL-10 and IFN-γ secreting cells compared to S. aureus alone. This was also confirmed in in vitro stimulations of PBMC with Lactobacillus and/or S. aureus strains, where S. aureus-induced IFN-γ production by Th cells was down regulated by co-stimulation with Lactobacillus. In paper II, we investigated the effects of UV-killed and/or culture supernatant (sn) of Lactobacillus strains and S. aureus strains on IEC and immune cell responses. IEC exposed to S. aureus-sn produced CXCL-1/GRO-α and CXCL-8/IL-8, while UV-killed bacteria had no effect. Further, PBMC from healthy donors exposed to Lactobacillus-sn and S. aureus-sn were able to produce a plethora of cytokines, but only S. aureus induced the T-cell associated cytokines: IL-2, IL-17, IFN-γ and TNF-α; which were down regulated by co-stimulation with any of the different Lactobacillus strains. Intracellular staining verified S. aureus-induced IFN-γ and IL-17 production by Th cells, and increased CTLA-4 expression and IL-10 production by T reg cells. In conclusion, we show that colonization with gut microbiota at early age modulates the cytokine response in infancy. In addition, bacterial species influence cytokine response in a species-specific manner and we demonstrate that lactobacilli modulate S. aureus-induced immune response away from an inflammatory phenotype.
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Pugine, Silvana Marina Piccoli. "Efeito do sistema ácido indol-3-acético/peroxidase de raiz forte sobre a viabilidade de Staphylococcus aureus." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-29042008-105235/.
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O objetivo do presente estudo foi avaliar a ação do ácido indol-3-acético (AIA) combinado com a peroxidase de raiz forte (HRP), formando um sistema gerador de espécies reativas de oxigênio, sobre a viabilidade de Staphylococcus aureus. Para tal, avaliou-se a viabilidade do S. aureus através da contagem das unidades formadoras de colônias após crescimento em ágar manitol, potencial e integridade de membrana por citometria de fluxo e integridade do DNA através de eletroforese em gel de poliacrilamida. Para realização dos ensaios foram utilizadas cepas de S. aureus recuperadas de casos de mastites clínicas. As cepas foram cultivadas em meio BHI (brain-heart-infusion) a 37ºC \"overnight\". Nos ensaios, o microrganismo foi incubado na ausência (controle) e presença de AIA (1 mmol/L)/HRP (1 µmol/L) em diferentes tempos (0, 1,5, 3 e 6 horas) a 37ºC. Foram realizados também ensaios contendo o microrganismo incubado na presença de AIA ou de HRP. O sistema AIA/HRP inibiu em 96%, 98%, 99% a formação de colônias do microrganismo para os tempos de 1,5, 3 e 6 horas, respectivamente, em relação ao controle em cada tempo. Ocorreu uma redução na polarização da membrana do microrganismo em 38, 69 e 99% nos tempos 1,5, 3 e 6 horas, respectivamente e uma diminuição significativa do número de microrganismos com membrana integra de 17 e 22% quando estes foram incubados por 3 e 6 horas, respectivamente em relação ao controle nos respectivos tempos. A adição das enzimas antioxidantes catalase ou superóxido dismutase ao meio de incubação não alterou o efeito deletério promovido pelo sistema AIA/HRP avaliado pelas unidades formadoras de colônias, despolarização e integridade de membrana. O sistema AIA/HRP não induziu a fragmentação do DNA do S. aureus após 3 e 6 horas de incubação. No presente estudo, foi possível verificar que a oxidação do AIA pela HRP produz uma resposta citotóxica potente capaz de promover a inibição do crescimento de S. aureus em ágar manitol, provocar a despolarização e a perda da integridade da membrana do microrganismo, sugerindo a possibilidade da utilização do sistema AIA/HRP como uma possível terapia alternativa contra bactérias.The objective of this study was to evaluate the action of the indole-3-acetic acid (IAA) in combination with horseradish peroxidase (HRP), forming a system generator of reactive oxygen species, on the viability of Staphylococcus aureus. To this end, was evaluated the of viability of S. aureus through the counting of the colony forming units after growth in mannitol agar, membrane potential and membrane integrity by flow cytometry and integrity of the DNA through the polyacrylamide gel electrophoresis. For the tests were used strains of S. aureus recovered from cases of clinical mastitis. The strains were grown in BHI medium (brain-heart-infusion) at 37°C overnight. In the tests, the microorganism was incubated in the absence (control) and presence of IAA (1 mmol/L)/HRP (1 µmol/L) at different times (0, 1.5, 3 and 6 hours) at 37°C. There were also conducted tests containing the microorganism incubated in the presence of IAA or HRP. The system IAA/HRP inhibited at 96%, 98%, 99% colony formation of microorganism to the times of 1.5, 3 and 6 hours, respectively, in relation to the control in every time. There was a decrease in polarization of the membrane of the microorganism on 38, 69 and 99% at times 1.5, 3 and 6 hours, respectively, and a significant decrease in the number of microorganisms with membrane integrity, 17 and 22% when they were incubated for 3 and 6 hours, respectively, in relation to the control in their time. The addition of the antioxidant enzymes catalase and superoxide dismutase in incubation medium did not alter the deleterious effect promoted by the system IAA/HRP assessed by colony forming units, membrane potential and membrane integrity. The system IAA/HRP did not induce the DNA fragmentation of S. aureus after 3 and 6 hours of incubation. In the present study, it was possible to verify that the oxidation of the IAA by HRP produces a potent cytotoxic response capable of promoting the inhibition of growth of S. aureus in mannitol agar, causing depolarization and the loss of integrity of the membrane of the microorganism, suggesting the possibility of using the system IAA/HRP as a possible alternative therapy against bacteria.
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Noto, Michael James. "Characterization of the Factors Associated with SCCmec Mobility in Staphylococcus Aureus." Also available to VCU users online at:, 2007. http://hdl.handle.net/10156/1556.
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Bleul, Lisa [Verfasser]. "The Sae two-component system of Staphylococcus aureus : sensing mechanism and impact on bacteria-phagocyte interaction / Lisa Bleul." Tübingen : Universitätsbibliothek Tübingen, 2021. http://d-nb.info/1238595065/34.
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Nascimento, Maristela da Silva do 1977. "Caracterização da atividade antimicrobiana e tecnologica de tres culturas bacteriocinogenicas e avaliação de sua eficiencia no controle de Listeria monocytogenes, Staphylococcus aureus e Bacillus cereus em queijo Minas frescal." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255710.
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Orientadores: Arnaldo Yoshiteru Kuaye, Izildinha MorenoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: A biopreservação é uma técnica utilizada para estender a vida útil e aumentar a segurança dos alimentos por meio do emprego de microbiota protetora e/ou seus peptídeos antimicrobianos. O objetivo deste trabalho foi avaliar a atividade antimicrobiana de culturas produtoras de bacteriocinas sobre alguns patógenos Gram-positivos de ocorrência comum em produtos lácteos. As culturas bacteriocinogênicas Lactococcus lactis subsp. Lactis ATCC 11454, Lactobacillus plantarum ALC 01 e Enterococcus faecium FAIR-E 198 apresentaram comportamento distinto em relação à produção de bacteriocinas quando inoculadas em caldo MRS e em leite desnatado reconstituído (LDR) a 10%. Na avaliação do espectro de ação antimicrobiano pelo método de difusão em ágar por inoculação em poços, as bacteriocinas produzidas por Lb. plantarum ALC 01 e E. faecium FAIR-E 198 apresentaram atividade inibitória apenas sobre as linhagens de Listeria monocytogenes, já a nisina produzida por Lc. lactis subsp. lactis ATCC 11454 demonstrou espectro de ação mais amplo, porém com menor atividade que as demais culturas bacteriocinogênicas. Na avaliação da compatibilidade de desenvolvimento associativo com fermentos lácticos comerciais, somente Lc. lactis subsp. lactis ATCC 11454 apresentou atividade (halo de 6mm) sobre as linhagens constituintes de ambos os fermentos lácticos avaliados. A determinação da atividade acidificante foi realizada em LDR 10% após 8 e 24h de incubação a 35ºC; a adição de 0,1% e de 0,5% das culturas bacteriocinogênicas não afetou significativamente a capacidade de acidificação dos fermentos lácticos. Além disso, observou-se que o desenvolvimento associativo dos fermentos lácticos com Lb. Plantarum ALC 01 e E. faecium FAIR-E 198, em ambas as concentrações, proporcionou significativo aumento da atividade das bacteriocinas destas culturas, enquanto que a atividade da nisina de Lc. lactis subsp. lactis ATCC 11454 foi suprimida. A atividade de aminopeptidases foi determinada após desenvolvimento das culturas lácticas em caldo MRS, Lb. Plantarum ALC 01 apresentou as maiores atividades. Também foi analisado o comportamento de patógenos Gram-positivos durante desenvolvimento associativo com as culturas produtoras de bacteriocinas e fermento láctico em LDR 10% a 35ºC por 48h. Lb. plantarum ALC 01 e E. faecium FAIR-E 198 não influenciaram significativamente o desenvolvimento de Bacillus cereus K1-B041 e de Staphylococcus aureus ATCC 27154 durante as primeiras 24h de incubação a 35ºC, contudo apresentaram forte ação inibitória sobre L monocytogenes Scott A. Já Lc. lactis subsp. lactis ATCC 11454 afetou o desenvolvimento de todos os patógenos apenas durante as primeiras 12h de incubação. O fermento láctico demonstrou significativa ação inibitória sobre B. cereus K1-B041 (>7,37 log UFC/ml) e L monocytogenes Scott A (>6,26 log UFC/ml). Em queijo Minas Frescal, não foi observada diferença significativa entre a ação das culturas bacteriocinogênicas e o fermento láctico sobre L. monocytogenes Scott A e S. aureus ATCC 27154. B. cereus K1-B041 demonstrou susceptibilidade a Lb. plantarum ALC 01 e E. faecium FAIR-E 198 após 7 dias. Pelo método de diluição crítica não foi detectada atividade de bacteriocina nos queijos durante os 21 dias de estocagem a 8 ± 1ºC. A adição das culturas produtoras de bacteriocinas como adjuntas ao queijo Minas Frescal não promoveu alteração no pH e na acidez, contudo Lb. plantarum ALC 01 e E. faecium FAIR-E 198 promoveram aumento da proteólise primária e secundária. Embora os resultados obtidos demonstrem que as culturas bacteriocinogênicas avaliadas não possam ser empregadas como único método de conservação, estas podem atuar em sinergia com outros fatores para aumentar a eficiência no controle de patógenos Gram-positivos, especialmente L. monocytogenes, em produtos lácteos fermentados
Abstract: The biopreservation system, such as bacteriocinogenic lactic bacteria cultures and/or their bacteriocins, have received increasing attention and new approaches to control pathogenic and spoilage microorganisms have been developed. The purpose of this study was to evaluate the action of bacteriocin-producing cultures (Lactococcus lactis subsp. lactis ATCC 11454, Lactobacillus plantarum ALC 01 and Enterococcus faecium FAIR-E 198) on some Gram-positive pathogens in different culture media and dairy products. The bacteriocin production was influenced by the media. The antimicrobial activity of these cultures was evaluated by agar-well diffusion assay. The bacteriocins produced by Lb. plantarum ALC 01 and E. faecium FAIR-E 198 presented inhibitory activity on Listeria monocytogenes alone, on the other hand, the nisin produced by Lc. lactis subsp. Lactis ATCC 11454 demonstrated wide action spectrum, albeit with lower activity. In compatibility of associative development evaluation with the commercial starter culture, only Lc. lactis subsp. lactis ATCC 11454 presented activity on the starter culture. The acidifier activity determination was carried out in skimmed milk after 8h and 24h of incubation at 35ºC. The addition of 0.1% and 0.5% of the bacteriocinogenic cultures did not affect the production of lactic acid by the starter culture. The associative development of the starter culture with Lb. plantarum ALC 01 and E. faecium FAIR-E 198 provided significant increase in bacteriocin activity of these cultures, while the activity of Lc. Lactis subsp. lactis ATCC 11454 nisin was suppressed. The aminopeptidase activity was determined after cellular lise of the lactic cultures previously grown in MRS broth. Lb plantarum ALC 01 presented the largest activity. Moreover, the behavior of Gram-positive pathogens was analyzed during co-culture with the bacteriocin-producing bacteria and with the starter culture in skimmed milk. Lb. plantarum ALC 01 and E. faecium FAIR-E 198 did not influence the development of Bacillus cereus K1-B041 and of Staphylococcus aureus ATCC 27154 during the first 24h of incubation at 35ºC. They presented strong inhibition on L. monocytogenes Scott A. Lc. lactis subsp. lactis ATCC 11454 affected the development of the pathogens studied during the first 12h of incubation. The starter culture demonstrated good inhibition of B. cereus K1-B041 (>7.37 log UFC/ml) and L monocytogenes Scott A (>6.26 log UFC/ml). In Minas Frescal cheese, significant difference was not observed between the action of the bacteriocinogenic cultures and the starter culture on L. monocytogenes Scott A and S. aureus ATCC 27154. B. cereus K1- B041 demonstrated susceptibility to Lb. plantarum ALC 01 and E. faecium FAIR-E 198 after 7 days. Bacteriocin activity was not detected in the cheeses during 21 days at 8 ± 1ºC. The addition of the bacteriocin-producing bacteria as an adjunct culture to the Minas Frescal cheese did not promote alteration in the pH and in the acidity, however Lb. plantarum ALC 01 and E. faecium FAIR-E 198 promoted an increase of the cheese proteolysis. Although the obtained results demonstrated that bacteriocinogenic cultures cannot be used as only method of conservation, these can be used as an additional barrier to optimize the control of Gram-positive pathogens, especially L. monocytogenes, in dairy products
Doutorado
Doutor em Tecnologia de Alimentos
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Silva, Helena Taina Diniz. "Potencial de compostos fenólicos como antimicrobianos e/ou moduladores da resistência em Staphylococcus aureus." Universidade Federal da Paraíba, 2015. http://tede.biblioteca.ufpb.br:8080/handle/tede/7501.
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Phenolic compounds are a major class of plant secondary metabolites synthesized for plant and adaptation to environmental stress defense. Are divided into three groups: phenolic acids, flavonoids and tannins. Have been proposed as having a variety of biological effects on human health and microorganisms such as S. aureus. Cases of infections caused by strains of S. aureus multi drug resistant (MDR) has increased over the years. Among the strategies to combat resistance of S. aureus to antibiotics, is the discovery of so-called modifiers resistance (Resistance-Modifying Agents - RMA). In this study, we evaluated the potential modulator and synergistic effect of flavonoids, tannins and phenolic acid on antibiotic activity norfloxanina (NOR), tetracycline (TET) and erythromycin (ERI) in strains of S. aureus. Six flavonoids have been tested - O-glycoside and C-glycoside - and their aglycone derivatives, two tannins (gallotannin and ellagitannin), phenolic acids (hydroxydiphenic acid and cinnamic acid derivatives). The compounds tested showed no antimicrobial activity at 128 μg/mL (MIC between 256 and 512 μg/mL). In the modulation test, the O-glycosylated flavonoids showed no reducing effect of the MIC of antibiotics tested, however, its aglycone derivatives reduced the MIC in the NOR sixteen fold (8 to 128 μg/mL), in contrast, the Cglycosylated flavonoids, quercetin and myricetin, reduced the MIC in the NOR up to four fold (32 to 128 μg/mL) and their aglycone derivatives showed no reducing effect MIC of the tested antibiotics; the hexahydroxydiphenic acid (gallic acid) showed no reducing effect of MIC of the tested antibiotics; among the cinnamic acid derivatives tested, only 3-methoxycinnamic acid, 3,4-dimethoxycinnamic acid and 3,4,5-trimethoxycinnamic acid reduced the MIC in the NOR (64 to 128 μg/mL), while the 3-methoxycinnamic acid presented reducing effect of tetracycline MIC (64 to 32 μg/mL); the ellagitannin (ellagic acid) showed no reducing effect of MIC of antibiotics tested, already the gallotannin (tannic acid - TA) reduced thirty-two fold the MIC NOR (128 to 4 μg/mL), the test checkerboard TA had effect synergistic when applied in combination with NOR (FICI = 0.15) TA MIC decreased from 512 to 64 μg/mL (eight fold) while the MIC of NOR decreased from 128 to 4 μg/mL (thirty-two fold). The results demonstrate that the phenolic compounds have a potential application as an adjunct to antibiotics, particularly when in combination with NOR.
Os compostos fenólicos constituem uma das principais classes de metabólitos secundários de plantas, sintetizados para a defesa vegetal e adaptação ao estresse ambiental. Estão subdivididos em três grupos: ácidos fenólicos, flavonoides e taninos. Têm sido propostos como tendo uma variedade de efeitos biológicos na saúde humana e sobre microrganismos como S. aureus. Casos de infecções provocadas por cepas de S. aureus multi droga resistentes (MDR) têm aumentando ao longo dos anos. Dentre as estratégias de combate à resistência de S. aureus a antibióticos, está a descoberta dos chamados agentes modificadores da resistência (RMA- resistance-modifying agents). Neste estudo, avaliamos o potencial modulador e efeito sinérgico de flavonoides, taninos e ácido fenólicos sobre a atividade antibiótica de norfloxanina (NOR), tetraciclina (TET) e eritromicina (ERI) em linhagens de S. aureus. Foram testados seis flavonoides - O-glicosídeo e C-glicosídeo - e seus derivados aglicona, dois taninos (galotanino e elagitanino), ácidos fenólicos (ácido hidroxidifênico e derivados do ácido cinâmico). Os compostos testados não apresentaram atividade antimicrobiana a 128 μg/mL (CIM entre 256 e 512 μg/mL). No teste de modulação, os flavonoides O-glicosilados não apresentaram efeito redutor da CIM dos antibióticos testados, no entanto, seus derivados aglicona reduziram a CIM da NOR em até dezesseis vezes (128 para 8 μg/mL), em contra partida, os flavonoides C-glicosilados, miricetrin e quercetrin, reduziram a CIM da NOR em até quatro vezes (128 para 32 μg/mL) e os seus derivados aglicona não apresentaram efeito redutor da CIM dos antibióticos testados; o ácido hexahidroxidifênico (ácido gálico) não apresentou efeito redutor da CIM dos antibióticos testados; dentre os derivados do ácido cinâmico ensaiados, apenas o ácido 3-metoxicinâmico, ácido 3,4-dimetoxicinâmico e ácido 3,4,5-trimetoxicinâmico reduziram a CIM da NOR (128 para 64 μg/mL), enquanto o ácido 3- metoxicinâmico, apresentou efeito redutor da CIM da tetraciclina (64 para 32 μg/mL); o elagitanino (ácido elágico) não apresentou efeito redutor da CIM dos antibióticos testados, já o galotanino (ácido tânico – AT) reduziu trinta e duas vezes a CIM da NOR (128 para 4 μg/mL), no teste checkerboard o AT apresentou efeito sinérgico quando aplicado em combinação com NOR (ICIF = 0,15) CIM do AT diminuiu de 512 para 64 μg/mL (oito vezes), enquanto a CIM da NOR diminuiu de 128 para 4 μg/mL (trinta e duas vezes). Os resultados obtidos demonstram que compostos fenólicos, possuem um potencial de aplicação como adjuvante de antibióticos, particularmente quando em uso combinado com NOR.
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Koripella, Srihari Nagendra Ravi Kiran. "Characterizing Elongation of Protein Synthesis and Fusidic Acid Resistance in Bacteria." Doctoral thesis, Uppsala universitet, Institutionen för cell- och molekylärbiologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-207924.
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Protein synthesis is a highly complex process executed by the ribosome in coordination with mRNA, tRNAs and translational protein factors. Several antibiotics are known to inhibit bacterial protein synthesis by either targeting the ribosome or the proteins factors involved in translation. Fusidic acid (FA) is a bacteriostatic antibiotic that blocks polypeptide chain elongation by locking elongation factor-G (EF-G) on the ribosome. Mutations in fusA, the gene encoding bacterial EF-G, confer high-level of resistance towards FA. Antibiotic resistance in bacteria is often associated with fitness loss, which is compensated by acquiring secondary mutations. In order to understand the mechanism of fitness loss and compensation in relation to FA resistance, we have characterized three S. aureus EF-G mutants with fast kinetics and crystal structures. Our results show that, the causes for fitness loss in the FA-resistant mutant F88L are resulting from significantly slower tRNA translocation and ribosome recycling. Analysis of the crystal structures, together with the results from our biochemical studies enabled us to propose that FA-resistant EF-G mutations causing fitness loss and compensation operate by affecting the conformational dynamics of EF-G on the ribosome. EF-G is a G-protein belonging to the GTPase super-family. In all the translational GTPases, a conserved histidine (H92 in E. coli EF-G) residue, located at the apex of switch II in the G-domain is believed to play a crucial role in ribosome-stimulated GTP hydrolysis and inorganic phosphate (Pi) release. Mutagenesis of H92 to alanine (A) and glutamic acid (E) showed different degree of defect in different steps of translation. Compared to wild type (WT) EF-G, mutant H92A showed a 10 fold defect in ribosome mediated GTP hydrolysis whereas the other mutant H92E showed a 100 fold defect. However, both the mutants are equally defective in single round Pi release (100 times slower than WT). When checked for their activity in mRNA translocation, H92A and H92E were 10 times and 100 times slower than WT respectively. Results from our tripeptide formation experiments revealed a 1000 fold defect for both mutants. Altogether, our results indicate that GTP hydrolysis occurs before tRNA translocation, whereas Pi release occurs probably after or independent of the translocation step. Further, our results confirm that, His92 has a vital role residue in ribosome-stimulated GTP hydrolysis and Pi release.
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Nwabueze, R. N. "The effect of growth conditions on cell envelope components in staphylococcus aureus." Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378840.
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Basso, Ana Cristina. "Aderência bacteriana: estudo in vitro de superfície de aço inoxidável e liga de titânio-alumínio-vanádio de uso ortopédico." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/82/82131/tde-05052010-094335/.
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O uso de metais na fabricação de implantes ortopédicos iniciou-se nas primeiras décadas do século XX. O aumento do uso de biomateriais implantáveis aumentam também os casos de infecção. A colonização da superfície do biomaterial pode ter início no momento da inserção do corpo estranho no organismo e geralmente é causada por microrganismos da microbiota da pele ou região adjacente ao implante. Este estudo teve por objetivo avaliar por métodos microbiológicos e microscópio eletrônico de varredura (MEV), a aderência bacteriana à superfície de aço inoxidável e liga de titânio de uso médico, bem como a molhabilidade da superfície destes metais. As bactérias usadas foram Staphylococcus epidermidis ATCC 12228 e Staphylococcus aureus ATCC 25923. Os discos de aço inoxidável (15,0 mm de diâmetro x 2,0 mm de espessura) e de liga de titânio (12,0 mm de diâmetro x 2,0 mm de espessura) foram inseridos, asséptica e separadamente, em tubos contendo 15,0 mL de caldo Mueller Hinton e 200,0 \'mü\'L de suspensão bacteriana da ordem de \'10 POT.8\' UFC/mL. Cada bactéria foi estudada individualmente. Os tubos foram incubados por 1, 6, 24, 48 e 72 horas sob agitação a 37 graus Celsius. Após os períodos de incubação, os discos foram retirados do caldo de cultura e submetidos ao banho de ultrassom em 5,0 mL de solução fisiológica 0,85% esterilizada. Deste líquido, foram realizadas diluições da ordem de \'10 POT.-1\' a \'10 POT.-4\' para a quantificação de células viáveis. Os valores foram expressos em UFC/mL. Para S. epidermidis sobre a liga de titânio, o número de células viáveis foi em 1 hora: 7,20 x \'10 POT.4\'; 6 horas: 3,90 x \'10 POT.6\'; 24 horas: 3,80 x \'10 POT.6\'; 48 horas: 9,70 x \'10 POT.6\' e 72 horas: 1,00 x \'10 POT.7\'. Sobre o aço inoxidável, o número de células viáveis foi em 1 hora: 3,00 x \'10 POT.3\'; 6 horas: 2,90 x \'10 POT.6\'; 24 horas: 3,20 x \'10 POT.6\'; 48 horas: 1,41 x \'10 POT.7\' e 72 horas: 1,88 x \'10 POT.7\'. Para S. aureus ) sobre a liga de titânio, o número de células viáveis foi em 1 hora: 2,00 x \'10 POT.3\'; 6 horas: 1,00 x \'10 POT.4\'; 24 horas: 3,10 x \'10 POT.4\'; 48 horas: 4,30 x \'10 POT.4\' e 72 horas: 5,80 x \'10 POT.3\'. Sobre o aço inoxidável, o número de células viáveis foi em 1 hora: 6,00 x \'10 POT.3\'; 6 horas: 2,00 x \'10 POT.3\'; 24 horas: 1,50 x \'10 POT.4\'; 48 horas: 3,20 x \'10 POT.5\' e 72 horas: 6,00 x \'10 POT.3\'. Ambas as superfícies metálicas foram caracterizadas como de média molhabilidade, onde a liga de titânio teve média \'+ OU -\' desvio padrão de 39,016 \'+ OU -\' 11,267 e o aço inoxidável 58,083 \'+ OU -\' 7,165. Tanto o S. aureus quanto o S. epidermidis aderiram às superfícies dos biomateriais estudados, como foi observado por meio de MEV. Com base nos resultados é possível concluir que os dois microrganismos são capazes de aderir a superfícies metálicas. Isto aumenta a preocupação quanto à patogênese das infecções relacionadas a implantes ortopédicos, uma vez que esses microrganismos estão presentes na pele humana e oferecem o risco de reações inflamatórias e infecção, promovendo a perda do implante para efetivar a cura.The utilization of metals in the manufacture of orthopedic implants started in first decades of twentieth century. The increased use of implantable biomaterials increased also infection cases. Biomaterial surface colonization can start at the moment of foreign body insertion in the organism and is usually caused by microorganisms of skin microbiota or adjacent region to the implant. This study aimed to evaluate microbiological methods and scanning electron microscopy (SEM), the bacterial adhesion to surface of stainless steel and titanium alloy of medical use, as well as the surface wetability of these metals. The used bacteria were Staphylococcus epidermidis ATCC 12228 and Staphylococcus aureus ATCC 25923. The stainless steel (15,0 mm diameter x 2,0 mm thick) and titanium alloy (12,0 mm diameter x 2,0 mm thick) discs were inserted, aseptic and individually, into tubes containing 15,0 mL Mueller Hinton broth and 200,0 \'mü\'L of bacterial suspension with \'10 POT.8\' CFU/mL concentration. Each bacterium was individually studied. The tubes were incubated for 1, 6, 24, 48 and 72 hours under agitation at 37 Celsius degrees. After incubation periods, the discs were removed from culture broth and submitted to the ultrasound bath in 5,0 mL of sterile saline. From this liquid were realized dilutions of \'10 POT.-1\' to \'10 POT.-4\' to quantify the viable cells. Values were expressed in CFU/mL. S. epidermidis over titanium alloy viable cells number was in 1 hour: 7,20 x \'10POT.4\'; 6 hours: 3,90 x \'10 POT.6\'; 24 hours: 3,80 x \'10 POT.6\'; 48 hours: 9,70 x \'10 POT.6\' and 72 hours: 1,00 x \'10 POT.7\'. Over stainless steel viable cells number was in 1 hour: 3,00 x \'10 POT.3\'; 6 hours: 2,90 x \'10 POT.6\'; 24 hours: 3,20 x \'10 POT.6\'; 48 hours: 1,41 x \'10 POT.7\' and 72 hours: 1,88 x \'10 POT.7\'. To S. aureus over titanium alloy viable cells number was in 1 hour: 2,00 x \'10 POT.3\'; 6 hours: 1,00 x \'10 POT.4\'; 24 hours: 3,10 x \'10 POT.4\'; 48 hours: 4,30 x \'10 POT.4\' and 72 hours: 5,80 x \'10 POT.3\' and over stainless steel viable cells number was in 1 hour: 6,00 x \'10 POT.3\'; 6 hours: 2,00 x \'10 POT.3\'; 24 hours: 1,50 x \'10 POT.4\'; 48 hours: 3,20 x \'10 POT.5\' and 72 hours: 6,00 x \'10 POT.3\'. Both metal surfaces were characterized as medium wetability, where the contact angle of titanium alloy was mean \'+ OU -\' standard deviation 39,016 \'+ OU -\' 11,267 and stainless steel 58,083 \'+ OU -\' 7,165. Both S. aureus as S. epidermidis adhered to surfaces of biomaterials studied, as observed by SEM. Based on the results we concluded that two microorganisms are able to adhere to metal surfaces. This increases the concern about the pathogenesis of infections related to orthopedic implants, since these microorganisms are present in human skin and provide the risk of infection and inflammatory reactions, furthering implant loss to effective cure.
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Saravia, Otten Patricia. "Studies on fibronectin binding proteins, proteases, and virulence in Staphylococcus aureus /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-108-3/.
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Bandeira, Fernando da Silva. "Bacterina de Staphylococcus aureus contendo própolis como adjuvante para controle da mastite." Universidade Federal de Pelotas, 2015. http://repositorio.ufpel.edu.br:8080/handle/prefix/3266.
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A mastite bovina é um problema sanitário mundial, com medidas de tratamento e prevenção insatisfatórias. Paralelamente, vem crescendo o interesse no uso de própolis como alternativa para tratamento das mastites, sendo ainda, objeto de estudos com finalidade de uso como adjuvante. Até o momento, porém, não foi descrito seu uso em vacinas para controle da mastite bovina. A importância do gênero Staphylococcus como agente da enfermidade é bem documentada, crescendo a necessidade de identificação da espécie do agente etiológico. A pesquisa identificou 12,6% de estafilococos coagulase positiva em mastites subclínicas na região sul do Brasil, sendo que S. aureus estando presente em 17,6% dos animais pesquisados. Dentre os isolados coagulase positiva, a frequência de S. aureus foi de 85,7%, a de S. intermedius foi de 8,5% e de S. hyicus foi 5,8%. A bactéria S. aureus utiliza vários fatores de patogenicidade para causar a infecção no hospedeiro. Foi pesquisado em bases de dados, as informações recentes sobre os principais produtos expressos e forma de atuação. Descreveu-se os principais mecanismos ligados a penetração do micro-organismo na glândula mamária, os processos que medeiam a formação do biofilme e suas estratégias de sobrevivência as respostas do hospedeiro, resultando em processos que muitas vezes tornam-se crônicos. Finalmente, é desejável a utilização de uma vacina eficiente para colaborar no controle da mastite, e dessa forma foi proposta a utilização de uma bacterina contendo extrato hidro-alcoólico de própolis verde na formulação. Comparou-se o seu efeito com uma formulação sem adição de própolis, vacina comercial e PBS esterilizado, em um trabalho conduzido em 63 bovinos. De forma semelhante, com os mesmos grupos de tratamento, mas com a adição de um grupo que recebeu apenas o extrato hidroalcoólico de própolis verde, foi conduzida uma pesquisa em 30 camundongos BALB/c. A pesquisa de anticorpos IgG em bovinos, demonstrou que tanto o tratamento contendo extrato hidroalcóolico de própolis verde quanto a bacterina sem própolis apresentaram resultados semelhantes, superiores aos tratamentos utilizando a vacina comercial e PBS, sendo que nos mesmos tratamentos, foi observada uma resposta com característica humoral inicialmente, tendendo a celular ao longo do experimento. Nos bovinos, a expressão relativa de RNAm para INF-γ, IL-2 e CXCR5 foi elevada para o grupo que recebeu a bacterina contendo extrato hidroalcoólico de própolis verde. Os resultados do teste de ELISA em camundongos, foram semelhantes aos encontrados para os bovinos. O grupo que recebeu apenas o extrato hidroalcoólico de própolis verde sem nenhuma combinação bacteriana, demonstrou resposta com predominância de IgG1 ao longo da pesquisa, semelhante aos grupos de vacina comercial e PBS. No modelo murino, a vacina comercial apresentou índices maiores de expressão de RNAm para as citocinas pesquisadas em esplenócitos. Os resultados obtidos sugerem que a bacterina contendo extrato hidroalcoólico de própolis verde apresenta potencial para atuar como ferramenta no controle da mastite bovina.
Bovine mastitis is a global health problem and many scientific advances have occurred, but the treatment and prevention of disease with existing techniques do not present satisfactory results. Similarly, there is growing interest in the use of propolis as an alternative for treatment of mastitis, also being the object of studies in order to use as an adjuvant, although so far it has not been described their use in vaccines for the control of bovine mastitis. The importance of Staphylococcus gender as disease agent is well documented, growing need for species identification of the etiologic agent. In a survey of coagulase-positive staphylococci in subclinical mastitis in southern Brazil, was finding its presence in 12.6% of cases with S. aureus was present in 17.6% of animal researched. Among the considered coagulase positive S. aureus is 85.7%, 8.5%, were S. intermedius and 5.8% were identified as S. hyicus. For the S. aureus penetrate, multiply and keep the host uses multiple pathogenic factors. Was researched in the literature to-date information on the main mechanisms expressed by the bacteria and how they operate, alone or integrated to ensure the penetration of micro-organism in the mammary gland, the processes that mediate the formation of biofilms and their coping strategies the host responses, their internalization in the cells and its continuation mechanisms, resulting in processes that often become chronic. To assist in the control of mastitis, is desirable the use of an effective vaccine and thus has been proposed the use of a bacterin containing hydroalcoholic extract of green propolis in the formulation is desirable, being compared to a similar bacterin without propolis, commercial vaccine and sterile PBS on a work carried out on 63 bovines. Similarly, with the same treatment groups and the addition of a group that received only the hydroalcoholic extract of propolis, a study was conducted on 30 BALB/c mice. The research of IgG antibodies in bovines showed that both treatment containing hydroalcoholic extract of propolis as the bacterin without propolis showed similar results and superior to commercial and PBS treatments, and the same treatment, we observed initially characteristic a humoral response with tending to cellular during throughout the experiment. In bovines, the relative expression of mRNA for INF-γ, IL-2 and CXCR5 was raised to the group receiving bacterin containing hidroalcoholic extract of green propolis. The ELISA results were similar to those of bovine in BALB/c still with the group that received only the the alcoholic extract of propolis without any bacterial combination, behaving similarly commercial and PBS, and the response was predominantly IgG1 to during the research. In the murine model, the commercial vaccine showed higher levels of mRNA expression for the studied cytokines. The results indicate that the bacterin containing alcoholic extract of propolis has the potential to act as a tool in the control of bovine mastitis in the target especie, requiring minor adjustments and a job to prove the efficiency in a challenge.
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Yanke, Shawna J. "Influence of in vitro bacterial urokinase responsiveness on the in vivo pathogenesis of methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus in mouse models." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/MQ49666.pdf.
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DIAZ, GALINDO EDAENA PAMELA 543391, and GALINDO EDAENA PAMELA DIAZ. "Detección de Staphylococcus aureus ORSA/MRSA en quesos frescos artesanales comercializados en mercados populares en el valle de toluca." Tesis de maestría, Universidad Autónoma del Estado de México, 2016. http://hdl.handle.net/20.500.11799/58793.
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Staphylococcus aureus es considerado la tercer causa más importante entre los patógenos transmitidos por alimentos y rápidamente ha adquirido resistencia a los antibióticos por lo que la portación asintomática en humanos y animales lo convierte en un serio problema cuando es transferido a los alimentos. El queso es un alimento listo para consumir que tiene una importante calidad nutricional y es un vehículo de crecimiento eficiente para transmitir enfermedades bacterianas cuando son consumidos sin pasteurización lo que ha llevado a que S. aureus sea frecuentemente aislado en estos productos. Los objetivos de este trabajo fueron 1) Determinar la presencia S. aureus por resistente a la meticilina (MRSA), la sensibilidad in vitro de los aislamientos, la detección del gen mecA y femB que codifican resistencia a antibióticos, el origen presuntivo mediante la técnica de biotipificación y la presencia de biofilm; y 2) determinar las características fisicoquímicas del queso fresco que se comercializa en el municipio de Toluca, Estado de México; así como el origen, formas de comercialización y condiciones de venta dada la importancia regional y económica del sistema de producción lechera y de la quesería artesanal en la zona. Se realizó un estudio transversal y muestreo por conveniencia, se adquirieron 64 piezas de quesos frescos en mercados itinerantes (tianguis) y fijos durante el periodo de agosto-octubre de 2014. El pH y la temperatura de los quesos se determinaron en el punto de venta, posteriormente mediante métodos oficiales se determinó el contenido de humedad, materia seca, cenizas, grasa, proteína y NaCl. La procedencia de los quesos se estableció a partir de la fuente de suministro en cuatro regiones: (A) Valle de Toluca; (B), otros municipios del Estado de México; (C) origen desconocido y (D) otros estados del país. Después de la realización de las pruebas bioquímicas se obtuvieron 17 aislamientos de Staphylococcus aureus. El patrón de sensibilidad in vitro mostró un alto porcentaje de resistencia a los β-lactámicos, se observaron altos porcentajes de resistencia en Penicilina (17/100%), ampicilina (16/94%), ceftazidima (16/94%), cefotaxima (10/58.8%) y amoxicilina/ácido clavulanico (9/53%). Sin embargo los aislamientos también mostraron sensibilidad a antibióticos como cefalotina (16/94%), tetraciclina (16/94%), trimetoprim-sulfametoxazol (16/94%), gentamicina (14/82.3%), oxacilina (13/76%), cefoxitina (15/88.2%), cefuroxima (12/70.5%), eritromicina (9/53%) respectivamente. Los 17 aislamientos de S. aureus se confirmaron al ser positivos al gen femB y no se detectó el gen mecA por PCR por lo que fueron considerados como Staphylococcus aureus sensibles a la meticilina (MSSA). La biotipificación mostró que 4(23.5%) fueron del ecovar humano, 2(11.8%) fueron del ecovar aves de corral, 1(5.9%) pertenecieron al ecovar ovino, y 10(58.8%) no tuvieron hospedero específico; finalmente 8 (47%) presentaron la coloración característica por la técnica de Rojo Congo. Se observó que la presentación del queso en su forma circular fue la misma en todos los puntos de venta con un rango de peso de 100 a 250 gr., los rangos para los parámetros fisicoquímicos fueron pH (4.84-6.07), humedad (42.71-66.66%), materia seca (1.68-3.39%), cenizas (2.65-5.24%), grasa (12-32%), proteína (16.81-26.62%) y NaCl (0.29-1.44%). Los resultados de esta investigación establecen la necesidad mejorar las políticas de higiene por las autoridades, asimismo para promover el uso racional de los antibióticos para evitar la aparición y propagación de cepas resistentes hacia quienes los manipulan y consumen, causando gran impacto en la salud pública. El queso fresco que se comercializa en la Ciudad de Toluca, puede ser considerado como un queso artesanal propio de la región, que debe de ser preservado como un interés en la gastronomía mexicana, además de la importancia de mejorar las condiciones de calidad e inocuidad en la comercialización.
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Soell, Martine. "Role des adhesines bacteriennes dans les interactions monocytes/bacteries : etude de leur activite pro-inflammatoire." Strasbourg 1, 1995. http://www.theses.fr/1995STR15106.
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Júnior, Flávio Ferraz de Campos. "Formação de biofilme bacteriano sobre polimetilmetacrilato usado como cimento ósseo." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/82/82131/tde-05052010-110709/.
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A infecção bacteriana é a principal complicação que um procedimento de artroplastia de quadril ou joelho pode apresentar. Mesmo após a incorporação de antibiótico (gentamicina) ao cimento ósseo, as taxas de infecções após este procedimento cirúrgico continuam gerando sérios prejuízos para o hospital e para o paciente. As principais bactérias envolvidas nas infecções relacionadas aos implantes ortopédicos são Pseudomonas aeruginosa, Staphylococcus aureus e Staphylococcus epidermidis. O objetivo deste trabalho foi avaliar a aderência e formação de biofilme de S. aureus, S. epidermidis e P. aeruginosa sobre o cimento ósseo polimetilmetacrilato (PMMA) com e sem antibiótico (gentamicina), de procedência nacional e internacional, por meio de microscópio eletrônico de varredura (MEV) e por cultura. Também, estimar quantitativamente as células viáveis recuperadas dos biofilmes formados. Foram produzidos discos de polimetilmetacrilato de 10,0 mm de diâmetro e 3,0 mm de espessura. Foram utilizadas cepas Pseudomonas aeruginosa - ATCC 27853, Staphylococcus epidermidis - ATCC 12228 e Staphylococcus aureus - ATCC 25932. Para este estudo foram utilizados corpos-de-prova de cimento ósseo de procedência nacional (BAUMER, CMM e BIOMECANICA) e internacional (BIOMET com gentamicina, BIOMET sem gentamicina e SIMPLEX). Biofilmes foram produzidos in vitro a partir da inoculação da suspensão bacteriana (\'10 POT.8\' unidades formadoras de colônia/mL) em Tryptic Soy Broth e incubados nos períodos de tempo de 1, 6, 24, 48, e 72 horas. Após os períodos de incubação os corpos-de-prova foram removidos do meio de cultura, lavados, sonicados e do sobrenadante realizadas diluições seriadas (\'10 POT.-1\' a \'10 POT.-5\'). A seguir, os corpos-de-prova foram preparados para observação por MEV. Os resultados de MEV mostraram bacilos e cocos aderidos e agrupados formando biofilme. Para P. aeruginosa: as contagens das células viáveis em média (UFC/mL) foram de 2,8 \'+ OU -\' 1,7 x \'10 POT.6\' (BAUMER), 1,7 \'+ OU -\' 0,9 x \'10 POT.6\' (BIOMECANICA), 1,7 \'+ OU -\' 0,7 x \'10 POT.6\' (CMM), 1,6 \'+ OU -\' 0,7 x \'10 POT.6\' (BIOMET sem gentamicina), 6,0 \'+ OU -\' 5,5 x \'10 POT.4\' (BIOMET com gentamicina) e 1,9 \'+ OU -\' 0,9 x \'10 POT.6\' (SIMPLEX); para S. epidermidis: 1,3 \'+ OU -\' 0,1 x \'10 POT.6\' (BAUMER), 1,5 \'+ OU -\' 0,2 x \'10 POT.6\' (BIOMECANICA), 2,3 \'+ OU -\' 1,7 x \'10 POT.6\' (CMM), 1,5 \'+ OU -\' 0,7 x \'10 POT.6\' (BIOMET sem gentamicina), 1,5 \'+ OU -\' 0,2 x \'10 POT.6\' (BIOMET com gentamicina) e 1,2 \'+ OU -\' 0,1 x \'10 POT.6\' (SIMPLEX); para S. aureus: 1,7 \'+ OU -\' 0,8 x \'10 POT.6\' (BAUMER), 1,6 \'+ OU -\' 0,7 x \'10 POT.6\' (BIOMECANICA), 1,4 \'+ OU -\' 0,6 x \'10 POT.6\' (CMM), 1,1 \'+ OU -\' 0,5 x \'10 POT.6\' (BIOMET sem gentamicina), 3,0 \'+ OU -\' 6,0 x \'10 POT.5\' (BIOMET com gentamicina) e 1,3 \'+ OU -\' 0,6 x \'10 POT.6\' (SIMPLEX), respectivamente. Os dados obtidos mostraram que o cimento ósseo de polimetilmetacrilato com e sem gentamicina não evitaram a aderência da Pseudomonas aeruginosa, Staphylococcus epidermidis e Staphylococcus aureus e formação de biofilme, como demonstrado pela MEV. Em conclusão, isto é um fator de risco para infecções.The bacterial infection is the main complication of a procedure for hip or knee arthroplasty can present. Even after the addition of antibiotic (gentamicin) in the bone cement, the rates of infection after the surgical procedure continue causing serious damage to the hospital and the patient. The main bacteria involved in infections related to orthopedic implants are Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis. The objective of this study was to evaluate the adhesion and biolfilm formation of the S. aureus, S. epidermidis and P. aeruginosa on the bone cement polymethylmethacrylate (PMMA) with and without antibiotic (gentamicin) from national and international origin, by means scanning electron microscope (SEM) and by culture. Also, quantitatively estimate the viable cells recovered from biofilms formed. Discs of cement were produced from 10.0 mm in diameter and 3.0 mm thick. Strains used were Pseudomonas aeruginosa - ATCC 27853, Staphylococcus epidermidis - ATCC 12228 e Staphylococcus aureus - ATCC 25932. For this study we used coupons cement of national origin (Baumer, CMM and biomechanics) and international (BIOMET with gentamicin, BIOMET without gentamicin and SIMPLEX). Biofilms were produced in vitro from the inoculation of bacterial suspension (108 Colony-Forming Units/mL) in Tryptic Soy Broth and incubated for the time periods of 1, 6, 24, 48 and 72 hours. After the incubation periods of the coupons they were removed from the medium culture, washed, sonicated and serial dilutions of supernatant taken (\'10 POT.-1\' a \'10 POT.-5\'). Next, the coupons were prepared for observation by SEM. The results of SEM showed adherent cocci bacilli, and adhered to each other form a biofilm. For P. aeruginosa: the couting of viable cells on average (CFU/mL) were 2,8 \'+ OU -\' 1,7 x \'10 POT.6\' (BAUMER), 1,7 \'+ OU -\' 0,9 x \'10 POT.6\' (BIOMECANICA), 1,7 \'+ OU -\' 0,7 x \'10 POT.6\' (CMM), 1,6 \'+ OU -\' 0,7 x \'10 POT.6\' (BIOMET sem gentamicina), 6,0 \'+ OU -\' 5,5 x \'10 POT.4\' (BIOMET com gentamicina) e 1,9 \'+ OU -\' 0,9 x \'10 POT.6\' (SIMPLEX); para S. epidermidis: 1,3 \'+ OU -\' 0,1 x \'10 POT.6\' (BAUMER), 1,5 \'+ OU -\' 0,2 x \'10 POT.6\' (BIOMECANICA), 2,3 \'+ OU -\' 1,7 x \'10 POT.6\' (CMM), 1,5 \'+ OU -\' 0,7 x \'10 POT.6\' (BIOMET sem gentamicina), 1,5 \'+ OU -\' 0,2 x \'10 POT.6\' (BIOMET com gentamicina) e 1,2 \'+ OU -\' 0,1 x \'10 POT.6\' (SIMPLEX); para S. aureus: 1,7 \'+ OU -\' 0,8 x \'10 POT.6\' (BAUMER), 1,6 \'+ OU -\' 0,7 x \'10 POT.6\' (BIOMECANICA), 1,4 \'+ OU -\' 0,6 x \'10 POT.6\' (CMM), 1,1 \'+ OU -\' 0,5 x \'10 POT.6\' (BIOMET sem gentamicina), 3,0 \'+ OU -\' 6,0 x \'10 POT.5\' (BIOMET com gentamicina) e 1,3 \'+ OU -\' 0,6 x \'10 POT.6\' (SIMPLEX), respectively. The data showed that of polymethylmethacrylate bone cement with and without gentamicin did not prevent the adhesion of Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus aureus and formation of biofilms, as demonstrated by SEM. In conclusion, this is risk factor for infections.
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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.
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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.