Letteratura scientifica selezionata sul tema "Biofilm-forming organisms"
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Articoli di riviste sul tema "Biofilm-forming organisms"
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Thi Minh Nguyet, Nguyen, Hoang Phuong Ha, Dong Van Quyen, Nguyen Ngoc Huong Tra e Le Thi Nhi Cong. "Degradation of naphthalene and pyrene by several biofilm-forming photosynthesis purple bacterial strains". Vietnam Journal of Biotechnology 18, n. 3 (28 novembre 2020): 561–70. http://dx.doi.org/10.15625/1811-4989/18/3/15322.
Testo completoAbstract (sommario):
Aromatic hydrocarbons such as naphthalene, pyrene are recalcitrant compounds found in oil contaminated areas including petroleum storage tanks, oil exploiting companies. These components are difficult to be degraded/transformed in the lack of oxygen conditions. Among anaerobic and micro-aerobic microorganisms, photosynthetic purple bacteria are the dominant group. Photosynthetic purple bacteria (PPB) are considered as aquatic organisms which are able to grow in anaerobic conditions by photosynthesis but without oxygen. This bacterial group has flexible metabolic types depending on living conditions, then they are widely distributed in nature. There are numerous publications on planktonic PPB which could use naphthalene and pyrene as carbon and energy sources. However, there is no publication on biofilm formed by PPB to degrade their aromatic compounds. In this research, 4 biofilm-forming PPB strains including DQ41, PY2, PY6 and DG12 were screened and estimated their pyrene and napthalene degradation capacity. These organisms demonstrated high biofilm forming ability. As biofilm types, their utilization efficiencies were upper 79% with the initial concentrations of naphthalene and pyrene of 200 and 250 ppm, respectively. These results may contribute to enlarge the number of biofilm-forming microorganisms to degrade/transform aromatic hydrocarbons in polluted area treatment in Vietnam.
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Banerjee, Soma, Abira Sahu, Shouvik Dutta, Rimashree Baishya e Prasanta Kumar Maiti. "Effect of different antibiotics against in vitro Staphylococcus aureus biofilm grown on chitin flakes". South Asian Journal of Experimental Biology 5, n. 1 (4 luglio 2015): 22–25. http://dx.doi.org/10.38150/sajeb.5(1).p22-25.
Testo completoAbstract (sommario):
MIC determination is the standard assay for testing the susceptibility of planktonic bacteria to antibiotics. It has been observed that biofilm grown cells express properties distinct from planktonic cells, for which antibiotics are generally not effective against biofilm forming organisms. The current study aims at comparison of the susceptibilities of biofilm grown cells to sin-gle antibiotic and in combination with others to identify those that were effective against Staphylococcus aureus biofilms. S. aureus ATCC 25923 were used for the purpose. They were grown in Tryptic Soya Broth (TSB) with chitin flakes as the inert surface to which the organisms adhered to produce the biofilm. Growth pattern of both biofilm producing and planktonic cells were studied. Viable counts were determined on Tryptic Soya Agar (TSA) plates. Different antibiotics viz. gentamicin, vancomycin, ciprofloxacin were used to determine the sensitivity of the bacterial strain. There was a marked differ-ence in antibiotic susceptibility between the planktonic and biofilm popula-tion of the organism. It was found that the biofilm colonies were more resistant to the antibiotics like ciprofloxacin, vancomycin and gentamicin than the planktonic cells. The reduction in growth of bacteria was much more for gentamicin compared to that of ciprofloxacin and vancomycin and when antibiotic combination gentamicin - vancomycin it is much more reduced. It is thus clear from the test that the antibiotic susceptibilities of planktonic populations are not necessarily applicable to the effective treatment of the same organism once a biofilm has been established.
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Lévesque, Céline M., Elena Voronejskaia, Yi-Chen Cathy Huang, Richard W. Mair, Richard P. Ellen e Dennis G. Cvitkovitch. "Involvement of Sortase Anchoring of Cell Wall Proteins in Biofilm Formation by Streptococcusmutans". Infection and Immunity 73, n. 6 (giugno 2005): 3773–77. http://dx.doi.org/10.1128/iai.73.6.3773-3777.2005.
Testo completoAbstract (sommario):
ABSTRACT Streptococcus mutans is one of the best-known biofilm-forming organisms associated with humans. We investigated the role of the sortase gene (srtA) in monospecies biofilm formation and observed that inactivation of srtA caused a decrease in biofilm formation. Genes encoding three putative sortase-dependent proteins were also found to be up-regulated in biofilms versus planktonic cells and mutations in these genes resulted in reduced biofilm biomass.
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Bhatta, Mahesh Prakash, Asmita Sapkota, Pushpa Subedi, Sunita Baniya Chhetri, Dhaka Raj Pant, Mukund Joshi, Santosh Pandit e Dipendra Raj Pandeya. "Biofilm Formation by Uropathogens and Their Susceptibility Towards Antimicrobial Therapy". Medical Journal of Shree Birendra Hospital 18, n. 1 (26 febbraio 2019): 13–22. http://dx.doi.org/10.3126/mjsbh.v18i1.20189.
Testo completoAbstract (sommario):
Introduction: Urinary tract infection (UTI) is the most common health care associated infection caused by various pathogenic bacteria. Biofilms are communities of bacteria that are held together by exopolymeric substances that protect against the antimicrobial therapy and other environmental assaults. The aim of this study was to estimate the prevalence of biofilm forming bacteria in Nepalese population and to study the emergence of antimicrobial resistance among biofilm producing bacteria in comparison to non-biofilm producing bacteria.
Methods: A total of 785 clean-caught-mid-stream urine samples were collected. After isolation and identification of uropathogens, they were further processed for detection of biofilm formation by two methods (Congo Red Agar method and Tissue Culture Plate method) as well as for antibiotic sensitivity test.
Results: Out of total collected samples, 12.74% were found to be associated with UTI, among them 67% were Escherichia coli, 10% were Klebsiella spp, 7% were Pseudomonas spp, 6% were Staphyloccous aureus, 4% were Enterobacter spp, 3% were Proteus spp, 2% were Citrobacter spp and remaining 1% was Staphylococcus saprophyticus. Among isolated organisms, the ratio of bioflim positive organism to bioflim negative organism was found to be 9:11. Nitrofurantoin, Tobramycin, Chloramphenicol, Amikacin and Imipenem were found to be significantly more sensitive in biofilm negative bacteria as compared to biofilm positive bacteria with p values of 0.000, 0.001, 0.000, 0.000 and 0.001.
Conclusions: The prevalence rate of multidrug resistance in bacterial uropathogens was higher in biofilm producers as compared to non-biofilm producers. Biofilm forming characteristic of bacteria make them more resistant to antibiotics.
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P., Prasanth, e Saravanakumari P. "DETECTION OF INTERCELLULAR ADHESION GENES (ICA) IN STAPHYLOCOCCUS AUREUS CAUSING IMPLANT ASSOCIATED INFECTIONS". International Journal of Pharmacy and Pharmaceutical Sciences 9, n. 10 (1 novembre 2017): 76. http://dx.doi.org/10.22159/ijpps.2017v9i11.20789.
Testo completoAbstract (sommario):
Objective:The complications related to implant associated infections in post-angioplasty patients were considered to increase due to biofilm formation.Methods: Genes responsible for the biofilm formation in the target organisms was investigated in the present study. The presence of the intercellular adhesion biofilm genes (icaA, icaB and icaD) was determined by the Polymerase Chain Reaction method. As preliminary investigations, standard tests, exit-site challenge test and microtitre plate method were used to study the biofilm efficiency of five different test organisms.Results: Exit-site challenge test, was used to identify the ability of test organisms to grow on a bio-materials used in the study. Among the five selected test organisms, Staphylococcus aureus showed the highest ability to colonize the stent materials with in 24h to 48h. In microtitre plate method, Staphylococcus aureus and Staphylococcus epidermidis showed high biofilm forming index values of 0.29 and 0.27 respectively. Biofilm gene studies using PCR revealed the presence of all the three ica genes (Ica A, Ica D and, Ica B) in Staphylococcus aureus. The present research finding has great significance in the treatment to implant associated infections.Conclusions: The results suggest that the virulence factors contributing to the development of infections can be revealed by understanding the presence of biofilm expression genes in the target organisms. This would also prevent dissemination of virulent bacteria in the health care centre; method also considered significant to detect healthy carriers of slime-producing staphylococci.
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Mireles, Joe Robert, Adam Toguchi e Rasika M. Harshey. "Salmonella enterica Serovar Typhimurium Swarming Mutants with Altered Biofilm-Forming Abilities: Surfactin Inhibits Biofilm Formation". Journal of Bacteriology 183, n. 20 (15 ottobre 2001): 5848–54. http://dx.doi.org/10.1128/jb.183.20.5848-5854.2001.
Testo completoAbstract (sommario):
ABSTRACT Swarming motility plays an important role in surface colonization by several flagellated bacteria. Swarmer cells are specially adapted to rapidly translocate over agar surfaces by virtue of their more numerous flagella, longer cell length, and encasement of slime. The external slime provides the milieu for motility and likely harbors swarming signals. We recently reported the isolation of swarming-defective transposon mutants of Salmonella enterica serovar Typhimurium, a large majority of which were defective in lipopolysaccharide (LPS) synthesis. Here, we have examined the biofilm-forming abilities of the swarming mutants using a microtiter plate assay. A whole spectrum of efficiencies were observed, with LPS mutants being generally more proficient than wild-type organisms in biofilm formation. Since we have postulated that O-antigen may serve a surfactant function during swarming, we tested the effect of the biosurfactant surfactin on biofilm formation. We report that surfactin inhibits biofilm formation of wild-type S. enterica grown either in polyvinyl chloride microtiter wells or in urethral catheters. Other bio- and chemical surfactants tested had similar effects.
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Cholo, Moloko C., Sipho S. M. Rasehlo, Eudri Venter, Chantelle Venter e Ronald Anderson. "Effects of Cigarette Smoke Condensate on Growth and Biofilm Formation by Mycobacterium tuberculosis". BioMed Research International 2020 (19 agosto 2020): 1–7. http://dx.doi.org/10.1155/2020/8237402.
Testo completoAbstract (sommario):
Background and Objectives. Cigarette smoke (CS) is a major risk factor contributing to the burden of tuberculosis. Little is known, however, about the effects of CS exposure on growth and persistence of Mycobacterium tuberculosis (Mtb) organisms. This issue has been addressed in the current study, which is focused on the effects of cigarette smoke condensate (CSC) on the growth and viability of Mtb planktonic and biofilm-forming cultures. Materials and Methods. The planktonic and biofilm-forming cultures were prepared in Middlebrook 7H9 and Sauton broth media, respectively, using Mtb strain, H37Rv. The effects of CSC at concentrations of 0.05-3.12 mg/L on growth, biofilm formation and structure were evaluated using microplate Alamar Blue assay, spectrophotometric procedure and scanning electron microscopy (SEM), respectively. Involvement of reactive oxygen species in CSC-mediated biofilm formation was investigated by including catalase in biofilm-forming cultures. Results. CSC did not affect the growth of planktonic bacteria, but rather led to a statistically significant increase in biofilm formation at concentrations of 0.4-3.12 mg/L, as well as in the viability of biofilm-forming bacteria at CSC concentrations of 0.2-1.56 mg/L. SEM confirmed an agglomerated biofilm matrix and irregular bacterial morphology in CSC-treated biofilms. Inclusion of catalase caused significant attenuation of CSC-mediated augmentation of biofilm formation by Mtb, implying involvement of oxidative stress. These findings demonstrate that exposure of Mtb to CSC resulted in increased biofilm formation that appeared to be mediated, at least in part, by oxidative stress, while no effect on planktonic cultures was observed. Conclusion. Smoking-related augmentation of biofilm formation by Mtb may contribute to persistence of the pathogen, predisposing to disease reactivation and counteracting the efficacy of antimicrobial chemotherapy.
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Fry, Stephen Eugene, Jeremy Eugene Ellis, Matthew Andrew Shabilla, Delyn Lorene Martinez, Renatta Schwarz, Richard Heuser e Constantine Moschonas. "Putative biofilm-forming organisms in the human vasculature: expanded and review of the literature". Phlebological Review 1 (2014): 24–37. http://dx.doi.org/10.5114/pr.2014.46050.
Testo completo
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Eid, Doaa, Ossama M. Sayed, Walaa G. Hozayen e Ahmed F. Azmy. "Battling Biofilm Forming Nosocomial Pathogens Using Chitosan and Pluronic F127". Journal of Pure and Applied Microbiology 14, n. 3 (22 settembre 2020): 1893–903. http://dx.doi.org/10.22207/jpam.14.3.28.
Testo completoAbstract (sommario):
Biofilm represents a potential strut in bacterial treatment failure. It has a dual action; it affords microbial resistance against antibiotics and facilitate transmission of pathogenic bacteria. Nosocomial bacteria pose a serious problem in healthcare units; it prolongs patient hospital stay and increases the mortality rates beside other awful economical effect. This study was planned for targeting nosocomial bacterial biofilm using natural and biologically safe compounds like Chitosan and/or Pluronic F127. Ninety-five isolates were recovered from 107 nosocomial clinical samples. Different bacterial and fungal species were detected, from which Klebsiella pneumonia (23%), Pseudomonas aeruginosa (19%), Acinetobacter baumannii (18%) and E.coli (17%) were the predominate organisms. Pseudomonas aeruginosa, Acinetobacter baumanni and Klebsiella pneumonia were the abundant antibiotic resistant strains with multi-resistance pattern of 72%, 65% and 59%, respectively. A significant percentage of these isolates were strong biofilm forming. Herein, we investigate the effect of Chitosan and Pluronic F127 alone and in combination with each other against biofilm production. Chitosan show variable degree of biofilm inhibition, while Pluronic F127 was able to retard biofilm formation by 80% to 90% in most strain. There is no significant difference (P< 0.05) between Pluronic F127 alone and its effect in combination with Chitosan.
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Pankhurst, Caroline L. "Risk Assessment of Dental Unit Waterline Contamination". Primary Dental Care os10, n. 1 (gennaio 2003): 5–10. http://dx.doi.org/10.1308/135576103322504030.
Testo completoAbstract (sommario):
Biofilms form rapidly on dental unit waterlines. The majority of the organisms in the biofilm are harmless environmental species, but some dental units may harbour opportunistic respiratory pathogens. This paper describes a risk assessment approach to analysing the hazard from biofilm organisms contaminating dental unit waterlines on the respiratory health of both the dental team and patients. The health risk from the respiratory pathogens Legionella spp, Mycobacterium spp and Pseudomonads was found to be low. Nevertheless, in order to satisfy water regulations and comply with health and safety legislation dentists should institute infection-control measures to maintain the dental unit water at the standard of less than 200 colony-forming units per ml of aerobic bacteria.
Tesi sul tema "Biofilm-forming organisms"
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Swanepoel, Amanda. "Transcriptional analysis and mutagenesis of the htp fimbrial gene cluster from Pseudomonas aeruginosa PAO1". Diss., 2006. http://hdl.handle.net/2263/26983.
Testo completoAbstract (sommario):
Pseudomonas aeruginosa, a ubiquitous environmental bacterium and an opportunistic human pathogen, is one of the most and best studied biofilm-forming organisms and has emerged as a model organism in the study of surface- and biofilm-induced gene expression. P. aeruginosa forms biofilms through a series of interactions between the cells and adherence to surfaces, which is mediated by surface appendages such as flagella and type IV pili. A gene cluster, designated htpABCDEFGI, which appears to encode protein products with homology to those encoded by recently described novel pilus biogenesis and assembly systems, has been identified in P. aeruginosa PAO1. Since the pili produced by these systems, designated Flp, are associated with the ability of the bacteria to bind non-specifically to inert surfaces, the aims of this study were to characterize the transcriptional organization of the putative P. aeruginosa PAO1 htp gene cluster and to determine the functional importance of the htp gene cluster in the ability of P. Aeruginosa PAO1 to adhere to surfaces. In silico evidence has suggested that the pilin subunit gene flp is not part of the P. Aeruginosa htp gene cluster thought to encode proteins involved in the synthesis, assembly and export of these pili. To determine the transcriptional organization of this gene cluster, total RNA from P. aeruginosa PAO1 was analyzed by reverse transcriptase-polymerase chain reaction (RTPCR). Primers designed to amplify regions spanning gene junctions yielded amplicons at each individual gene junction from htpA to htpI, as well as an amplicon for flp. Moreover, corresponding sigma 70 (σ70) consensus sequences were identified in the intergenic region between the htpA and flp genes and promoter function of the flp and htpA upstream region was subsequently confirmed using lacZ reporter gene constructs transformed into P.aeruginosa PAO1. The results therefore indicated that the htp gene cluster is an operon transcribed as a polycistronic message, whilst the flp gene is transcribed independently as a monocistronic message. To determine the functional importance of thehtp gene cluster in P. aeruginosa PAO1, the htpD gene, encoding a putative NTPase, was inactivated by in vivo homologous recombination with an appropriately constructed allelic exchange vector to generate the isogenic mutant strain PAOHtpD. Comparative analysis of the wild-type P. aeruginosa PAO1 and mutant PAOHtpD strain revealed that the mutant strain was impaired in its ability to attach to a glass wool substratum and also in its ability to grow as a biofilm. Since the mutant PAOHtpD strain was not growth-impaired, these results indicate that the htp gene cluster plays a role in P. aeruginosa PAO1 biofilm development under the culturing conditions used in this study. Thus, it can be proposed that the flp and htp gene cluster of P. aeruginosa PAO1 may play a role in its ability to successfully colonize abiotic surfaces.Dissertation (MSc)--University of Pretoria, 2010.
Microbiology and Plant Pathology
unrestricted
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Steyn, Bridgitta. "Proteomic analysis of the biofilm and biofilm-associated phenotypes of Pseudomonas aeruginosa cultured in batch". Thesis, 2006. http://hdl.handle.net/2263/29311.
Testo completoAbstract (sommario):
Pseudomonas aeruginosa is one of the most studied biofilm-forming organisms and has emerged as a model organism in the study of surface- and biofilm-induced gene expression. The transition from a planktonic to a biofilm mode of growth results in diverse changes in gene expression, which causes the attaching cells to become phenotypically and metabolically distinct from their planktonic counterparts. In this study, a proteomic approach was used to study differences in protein profiles obtained from 18-h old P. aeruginosa PAO1 (DSM 1707) planktonic, surface influenced planktonic (SIP) and biofilm populations grown in batch in the absence or presence of a glass wool substratum. Glass wool as an attachment substratum not only supported growth of biofilms, but it also allowed for the separation of the biofilm biomass from the surrounding surface influenced planktonic (SIP) cells for further characterisation. Comparative analysis of the respective proteomes indicated striking differences in the protein patterns of planktonic, biofilm and SIP cells and several uniquely expressed proteins were seen on the 2-DE protein maps of the respective populations. Whereas a general down-regulation of protein expression was seen in the biofilm cells, in SIP cells, expression of the proteins was generally up-regulated. The results confirmed that the biofilm population differs from the planktonic population and indicated that the SIP population is not merely a mixture of planktonic and biofilm cells but rather a unique phenotype. Several differentially expressed protein spots were selected and identified using a combination of N-terminal protein sequencing and peptide mass fingerprinting. The proteins comprised mostly of outer membrane or membrane-associated proteins. Based on these analyses, a mutant P. aeruginosa strain, deficient in outer membrane protein OprG, was generated and its ability to form biofilms on a glass wool substratum was compared with that of the wild-type P. aeruginosa strain. The mutant strain was attachment-proficient but biofilm-deficient, suggesting that OprG plays a role in P. aeruginosa biofilm development under the culturing conditions used in this study.Thesis (PhD (Microbiology))--University of Pretoria, 2007.
Microbiology and Plant Pathology
unrestricted
Capitoli di libri sul tema "Biofilm-forming organisms"
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Gebauer, Paulina, Luis Giménez, Iván Hinojosa e Kurt Paschke. "Settlement and Metamorphosis in Barnacles and Decapods". In Developmental Biology and Larval Ecology, 223–54. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190648954.003.0008.
Testo completoAbstract (sommario):
Settlement and metamorphosis are two crucial processes in organisms with a biphasic life cycle, forming the link between the pelagic larva and benthic juvenile-adult. In general, these processes occur during the final larval stage. Among crustaceans, settlement behavior and the cues that trigger settlement and metamorphosis have been studied in greater depth in barnacles than in decapods, likely a result of the former losing the ability to move after they join the benthic juvenile-adult population, undergoing metamorphosis. Both barnacles and decapods respond to different environmental cues associated with the adult habitat, such as substratum, biofilm, and the presence of conspecifics. In the absence of cues, larvae can delay their metamorphosis for a period of time. This ability to prolong the development can be advantageous because it increases the probability of settling in a suitable habitat. However, delayed metamorphosis has also associated costs (e.g., smaller size, lower growth rate, and higher mortality), which may be carried over to subsequent development stages, with consequences for recruitment.