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Journal of Medical Microbiology Jul 2016
Topics: Anti-Bacterial Agents; Genotype; Humans; Microbial Sensitivity Tests; Multilocus Sequence Typing; Pseudomonas Infections; Pseudomonas aeruginosa; Sequence Analysis, DNA; United Kingdom; beta-Lactam Resistance; beta-Lactamases; beta-Lactams
PubMed: 27126265
DOI: 10.1099/jmm.0.000269 -
International Journal of Environmental... Feb 2011Pseudomonas aeruginosa is an important opportunistic pathogen in recreational waters and the primary cause of hot tub folliculitis and otitis externa. The aim of this...
Pseudomonas aeruginosa is an important opportunistic pathogen in recreational waters and the primary cause of hot tub folliculitis and otitis externa. The aim of this surveillance study was to determine the background prevalence and antimicrobial resistance profile of P. aeruginosa in swimming pools and hot tubs. A convenience sample of 108 samples was obtained from three hot tubs and eight indoor swimming pools. Water and swab samples were processed using membrane filtration, followed by confirmation with polymerase chain reaction. Twenty-three samples (21%) were positive for P. aeruginosa, and 23 isolates underwent susceptibility testing using the microdilution method. Resistance was noted to several antibiotic agents, including amikacin (intermediate), aztreonam, ceftriaxone, gentamicin, imipenem, meropenem (intermediate), ticarcillin/clavulanic acid, tobramycin (intermediate), and trimethoprim/sulfamethoxazole. The results of this surveillance study indicate that 96% of P. aeruginosa isolates tested from swimming pools and hot tubs were multidrug resistant. These results may have important implications for cystic fibrosis patients and other immune-suppressed individuals, for whom infection with multidrug-resistant P. aeruginosa would have greater impact. Our results underlie the importance of rigorous facility maintenance, and provide prevalence data on the occurrence of antimicrobial resistant strains of this important recreational water-associated and nosocomial pathogen.
Topics: Drug Resistance, Multiple, Bacterial; Hot Temperature; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Swimming Pools
PubMed: 21556203
DOI: 10.3390/ijerph8020554 -
Biofouling Aug 2019Food wasted due to food spoilage remains a global challenge to the environmental sustainability and security of food supply. In food manufacturing, post-processing...
Food wasted due to food spoilage remains a global challenge to the environmental sustainability and security of food supply. In food manufacturing, post-processing contamination of food can occur due to persistent bacterial biofilms, which can be resistant to conventional cleaning and sanitization. The objective was to characterize the efficacy of a polymeric coating in reducing biofilm establishment and facilitating its removal. Viable cell density of a 48 h biofilm was reduced by 2.10 log cfu cm on the coated surface, compared to native polypropylene. Confocal laser scanning and electron microscopy indicated reductions in mature biofilm viability and thickness on the coated material. The antifouling coating improved cleanability, with ∼2.5 log cfu cm of viable cells remaining after 105 min cleaning by water at 65 °C, compared to 4.5 log cfu cm remaining on native polypropylene. Such coatings may reduce the persistence of biofilms in food processing environments, in support of reducing food spoilage and waste.
Topics: Anti-Bacterial Agents; Biofilms; Pseudomonas aeruginosa
PubMed: 31550928
DOI: 10.1080/08927014.2019.1660774 -
Antimicrobial Agents and Chemotherapy Apr 1977A plasmid, R56Be, derived from a clinical strain of Pseudomonas aeruginosa isolated in France in 1973 has been studied. This plasmid confers resistance only to...
A plasmid, R56Be, derived from a clinical strain of Pseudomonas aeruginosa isolated in France in 1973 has been studied. This plasmid confers resistance only to carbenicillin, and although freely transferable between unrelated strains of P. aeruginosa, its transfer from P. aeruginosa to Escherichia coli K-12 was undetectable. R56Be could not be isolated as covalently closed circular deoxyribonucleic acid, but the plasmid could be transduced intact by phage F116L. This suggests that its molecular weight does not exceed that of the phage genome (ca. 40 x 10(6)). In terms of its interaction with male and female sex-specific phages, its exclusion characteristics, and the main properties of beta-lactamase determined by them, R56Be is similar to the previously characterized plasmid RP1-1.
Topics: Carbenicillin; Extrachromosomal Inheritance; Penicillin Resistance; Plasmids; Pseudomonas aeruginosa
PubMed: 404966
DOI: 10.1128/AAC.11.4.589 -
Giornale Di Batteriologia, Virologia Ed... 1986Serotyping of Pseudomonas aeruginosa by Fisher's schema has been used to study the prevalence of particular immunotypes among strains of P. aeruginosa obtained from... (Review)
Review
Serotyping of Pseudomonas aeruginosa by Fisher's schema has been used to study the prevalence of particular immunotypes among strains of P. aeruginosa obtained from clinical specimens. About 78% of the isolates were serotypable and about 22% were not. Immunotypes 2 and 6 turned out to be the most prevalent, whereas immunotypes 5 and 7 were the least frequent. Immunotypes 2, 5, 6 and 7 did not vary significantly as far as frequency in the various sources is concerned, with the exception of immunotype 2, which was significantly less frequent in isolates from the expectorated sputum. In such isolates immunotype 3 was significantly more frequent than in other sources, whereas immunotype 4 was significantly more frequent in isolates from the feces. It was next investigated whether a correlation exists between antibiotic susceptibility and particular immunotypes. A high percentage of the non-typable strains and of those belonging to immunotypes 2 and 6 proved to be resistant to the antimicrobial agents tested.
Topics: Humans; Microbial Sensitivity Tests; Pseudomonas aeruginosa
PubMed: 3119410
DOI: No ID Found -
Communications Biology 2019Bacterial viruses, or phage, are key members of natural microbial communities. Yet much research on bacterial-phage interactions has been conducted in liquid cultures...
Bacterial viruses, or phage, are key members of natural microbial communities. Yet much research on bacterial-phage interactions has been conducted in liquid cultures involving single bacterial strains. Here we explored how bacterial diversity affects the success of lytic phage in structured communities. We infected a sensitive strain PAO1 with a lytic phage Pseudomonas 352 in the presence versus absence of an insensitive strain PA14, in liquid culture versus colonies on agar. We found that both in liquid and in colonies, inter-strain competition reduced resistance evolution in the susceptible strain and decreased phage population size. However, while all sensitive bacteria died in liquid, bacteria in colonies could remain sensitive yet escape phage infection, due mainly to reduced growth in colony centers. In sum, spatial structure can protect bacteria against phage infection, while the presence of competing strains reduces the evolution of resistance to phage.
Topics: Biofilms; Host Microbial Interactions; Microscopy, Electron, Transmission; Models, Biological; Pseudomonas Phages; Pseudomonas aeruginosa; Species Specificity
PubMed: 31701033
DOI: 10.1038/s42003-019-0633-x -
ACS Chemical Biology Apr 2016The opportunistic pathogen Pseudomonas aeruginosa utilizes multiple quorum sensing (QS) pathways to coordinate an arsenal of virulence factors. We previously identified...
The opportunistic pathogen Pseudomonas aeruginosa utilizes multiple quorum sensing (QS) pathways to coordinate an arsenal of virulence factors. We previously identified several cysteine-based compounds inspired by natural products from the plant Petiveria alliacea which are capable of antagonizing multiple QS circuits as well as reducing P. aeruginosa biofilm formation. To understand the global effects of such compounds on virulence factor production and elucidate their mechanism of action, RNA-seq transcriptomic analysis was performed on P. aeruginosa PAO1 exposed to S-phenyl-l-cysteine sulfoxide, the most potent inhibitor from the prior study. Exposure to this inhibitor down-regulated expression of several QS-regulated virulence operons (e.g., phenazine biosynthesis, type VI secretion systems). Interestingly, many genes that were differentially regulated pertain to the related metabolic pathways that yield precursors of pyochelin, tricarboxylic acid cycle intermediates, phenazines, and Pseudomonas quinolone signal (PQS). Activation of the MexT-regulon was also indicated, including the multidrug efflux pump encoded by mexEF-oprN, which has previously been shown to inhibit QS and pathogenicity. Deeper investigation of the metabolites involved in these systems revealed that S-phenyl-l-cysteine sulfoxide has structural similarity to kynurenine, a precursor of anthranilate, which is critical for P. aeruginosa virulence. By supplementing exogenous anthranilate, the QS-inhibitory effect was reversed. Finally, it was shown that S-phenyl-l-cysteine sulfoxide competitively inhibits P. aeruginosa kynureninase (KynU) activity in vitro and reduces PQS production in vivo. The kynurenine pathway has been implicated in P. aeruginosa QS and virulence factor expression; however, this is the first study to show that targeted inhibition of KynU affects P. aeruginosa gene expression and QS, suggesting a potential antivirulence strategy.
Topics: Hydrolases; Pseudomonas aeruginosa; Quorum Sensing; Virulence
PubMed: 26785289
DOI: 10.1021/acschembio.5b01082 -
The Journal of Antimicrobial... Mar 2019
Topics: Gene Order; Humans; Plasmids; Pseudomonas Infections; Pseudomonas aeruginosa; beta-Lactamases
PubMed: 30403778
DOI: 10.1093/jac/dky454 -
Proceedings of the National Academy of... Feb 2015The bacterium Pseudomonas aeruginosa is an opportunistic human pathogen that uses a quorum sensing signal cascade to activate expression of dozens of genes when...
The bacterium Pseudomonas aeruginosa is an opportunistic human pathogen that uses a quorum sensing signal cascade to activate expression of dozens of genes when sufficient population densities have been reached. Quorum sensing controls production of several key virulence factors, including secreted proteases such as elastase. Cooperating groups of bacteria growing on protein are susceptible to social cheating by quorum-sensing defective mutants. A possible way to restrict cheater emergence is by policing where cooperators produce costly goods to sanction or punish cheats. The P. aeruginosa LasR-LasI quorum sensing system controls genes including those encoding proteases and also those encoding a second quorum-sensing system, the RhlR-RhlI system, which controls numerous genes including those for cyanide production. By using RhlR quorum sensing mutants and cyanide synthesis mutants, we show that cyanide production is costly and cyanide-producing cooperators use cyanide to punish LasR-null social cheaters. Cooperators are less susceptible to cyanide than are LasR mutants. These experiments demonstrate policing in P. aeruginosa, provide a mechanistic understanding of policing, and show policing involves the cascade organization of the two quorum sensing systems in this bacterium.
Topics: Cyanides; Mutation; Pseudomonas aeruginosa; Quorum Sensing; Virulence
PubMed: 25646454
DOI: 10.1073/pnas.1500704112 -
Nature Microbiology May 2024
Topics: Pseudomonas aeruginosa; Anti-Bacterial Agents; Humans; Pseudomonas Infections; Microbial Sensitivity Tests
PubMed: 38641709
DOI: 10.1038/s41564-024-01673-2