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FEMS Microbiology Reviews Jul 2014Members of the Pseudomonas genus produce diverse secondary metabolites affecting other bacteria, fungi or predating nematodes and protozoa but are also equipped with the... (Review)
Review
Members of the Pseudomonas genus produce diverse secondary metabolites affecting other bacteria, fungi or predating nematodes and protozoa but are also equipped with the capacity to secrete different types of ribosomally encoded toxic peptides and proteins, ranging from small microcins to large tailocins. Studies with the human pathogen Pseudomonas aeruginosa have revealed that effector proteins of type VI secretion systems are part of the antibacterial armamentarium deployed by pseudomonads. A novel class of antibacterial proteins with structural similarity to plant lectins was discovered by studying antagonism among plant-associated Pseudomonas strains. A genomic perspective on pseudomonad bacteriocinogeny shows that the modular architecture of S pyocins of P. aeruginosa is retained in a large diversified group of bacteriocins, most of which target DNA or RNA. Similar modularity is present in as yet poorly characterized Rhs (recombination hot spot) proteins and CDI (contact-dependent inhibition) proteins. Well-delimited domains for receptor recognition or cytotoxicity enable the design of chimeric toxins with novel functionalities, which has been applied successfully for S and R pyocins. Little is known regarding how these antibacterials are released and ultimately reach their targets. Other remaining issues concern the identification of environmental triggers activating these systems and assessment of their ecological impact in niches populated by pseudomonads.
Topics: Anti-Bacterial Agents; Bacterial Secretion Systems; Deoxyribonucleases; Peptides; Pseudomonas aeruginosa; Pyocins
PubMed: 24923764
DOI: 10.1111/1574-6976.12079 -
Emerging Infectious Diseases 1998Pseudomonas aeruginosa is a bacterium responsible for severe nosocomial infections, life-threatening infections in immunocompromised persons, and chronic infections in... (Review)
Review
Pseudomonas aeruginosa is a bacterium responsible for severe nosocomial infections, life-threatening infections in immunocompromised persons, and chronic infections in cystic fibrosis patients. The bacterium's virulence depends on a large number of cell-associated and extracellular factors. Cell-to-cell signaling systems control the expression and allow a coordinated, cell-density-dependent production of many extracellular virulence factors. We discuss the possible role of cell-to-cell signaling in the pathogenesis of P. aeruginosa infections and present a rationale for targeting cell-to-cell signaling systems in the development of new therapeutic approaches.
Topics: Animals; Humans; Pseudomonas Infections; Pseudomonas aeruginosa; Signal Transduction; Virulence
PubMed: 9866731
DOI: 10.3201/eid0404.980405 -
Microbiological Research Dec 2016Multidrug-resistant (MDR) Pseudomonas aeruginosa VRFPA04, obtained from a keratitis patient was found to exhibit resistance to betalactam (Penicillins, cephalosporins,...
Multidrug-resistant (MDR) Pseudomonas aeruginosa VRFPA04, obtained from a keratitis patient was found to exhibit resistance to betalactam (Penicillins, cephalosporins, including carbapenems, except aztreonam), aminoglycosides, quinolone group of drugs and susceptible to colistin. The complete genome sequencing of the ocular isolate to measure and ascertain the degree of multidrug resistance in VRFPA04 strain resulted in 6,818,030bp (6.8Mb) genome sizes, which happen to be the third largest genome available in the Genbank to date. Two chromosomally integrated class I integrons carrying bla carbapenemase gene, multiple secretory systems consisting of types I-VI and VIII proteins and ocular virulence factors exo-T, Y, U and exotoxin A, a gene that inhibits protein synthesis which could have caused corneal cell death and Phytohormone auxin biosynthetic protein were detected in the genome of VRFPA04 Genome. In addition, 58 Regions of Genomic Plasticity (RGPs) regions, multiple phage genomes, genomic islands, CRISPR genes and RND family efflux pumps, such as MexCD-OprJ and MexEF-OprN and its regulators, MexT and MexR, were unraveled in VRFPA04. Thus, the current study reveals the virulence factors and resistome nature of an ocular isolate P aeruginosa VRFPA04 genome.
Topics: DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Genes, Bacterial; Genome, Bacterial; Humans; Interspersed Repetitive Sequences; Keratitis; Pseudomonas Infections; Pseudomonas aeruginosa; Sequence Analysis, DNA
PubMed: 27825482
DOI: 10.1016/j.micres.2016.10.002 -
Annals of Clinical Microbiology and... Feb 2021Pseudomonas aeruginosa an opportunistic pathogen, is widely associated with nosocomial infections and exhibits resistance to multiple classes of antibiotics. The aim of...
Evaluation of efflux pump activity and biofilm formation in multidrug resistant clinical isolates of Pseudomonas aeruginosa isolated from a Federal Medical Center in Nigeria.
BACKGROUND
Pseudomonas aeruginosa an opportunistic pathogen, is widely associated with nosocomial infections and exhibits resistance to multiple classes of antibiotics. The aim of this study was to determine the antibiotic resistance profile, biofilm formation and efflux pump activity of Pseudomonas strains isolated from clinical samples in Abeokuta Ogun state Nigeria.
METHODS
Fifty suspected Pseudomonas isolates were characterized by standard biochemical tests and PCR using Pseudomonas species -specific primers. Antibiotic susceptibility testing was done by the disc diffusion method. Efflux pump activity screening was done by the ethidium bromide method and biofilm formation assay by the tissue plate method. Genes encoding biofilm formation (pslA & plsD) and efflux pump activity (mexA, mexB and oprM) were assayed by PCR.
RESULTS
Thirty-nine Pseudomonas spp. were identified of which 35 were Pseudomonas aeruginosa and 4 Pseudomonas spp. All 39 (100%) Pseudomonas isolates were resistant to ceftazidime, cefuroxime and amoxicillin-clavulanate. Thirty-six (92%), 10(25.6%), 20 (51.2%), 11(28%) and 9(23%) of the isolates were resistant to nitrofurantoin, imipenem, gentamicin, cefepime and aztreonam respectively. All the isolates had the ability to form biofilm and 11 (28%) of them were strong biofilm formers. They all (100%) harboured the pslA and pslD biofilm encoding genes. Varied relationships between biofilm formation and resistance to ciprofloxacin, ofloxacin, cefixime, gentamicin, imipenem, and aztreonam were observed. Only 23(59%) of the Pseudomonas isolates phenotypically exhibited efflux pump activity but mexA gene was detected in all 39 (100%) isolates while mexB and oprM genes were detected in 91%, 92%, and 88% of strong, moderate and weak biofilm formers respectively.
CONCLUSION
Multidrug resistance, biofilm and efflux pump capabilities in Pseudomonas aeruginosa have serious public health implications in the management of infections caused by this organism.
Topics: Bacterial Outer Membrane Proteins; Biofilms; Drug Resistance, Multiple, Bacterial; Humans; Membrane Transport Proteins; Phenotype; Pseudomonas aeruginosa
PubMed: 33531042
DOI: 10.1186/s12941-021-00417-y -
Postepy Higieny I Medycyny... Jul 2017The effectiveness of carbapenems, considered as last-resort antimicrobials in severe infections, becomes compromised by bacterial resistance. The production of...
The effectiveness of carbapenems, considered as last-resort antimicrobials in severe infections, becomes compromised by bacterial resistance. The production of metallo-β-lactamases (MBLs) is the most significant threat to carbapenems activity among Pseudomonas aeruginosa. The aim of this study was to assess the presence and type of MBLs genes in carbapenem-resistant P. aeruginosa clinical strains, to identify the location of MBLs genes and to determine genetic relatedness between MBL-producers using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The first identified MBL-positive (with blaVIM genes) P. aeruginosa strains were isolated from patients hospitalized in the University Clinical Hospital of Bialystok in the period from September 2012 to December 2013. Variants of MBLs genes and variable integron regions were characterized by PCR and sequencing. PFGE was performed after digesting of bacterial genomes by XbaI enzyme. By MLST seven housekeeping genes were analyzed for the determination of sequence type (ST). Three strains carried the blaVIM-2 gene and one harbored the blaVIM-4 gene. The blaVIM genes resided within class 1 integrons. PCR mapping of integrons revealed the presence of four different cassette arrays. Genetic relatedness analysis by PFGE classified VIM-positive strains into four unrelated pulsotypes (A-D). MLST demonstrated the presence of four (ST 111, ST27, and ST17) different sequence type including one previously undescribed new type of ST 2342. Antimicrobial susceptibility testing showed that VIM-positive strains were resistant to carbapenems, cephalosporins, aminoglycosides, and quinolones, intermediate to aztreonam, and susceptible only to colistin. Integrons mapping, PFGE, and MLST results may point to different origin of these strains and independent introduction into hospitalized patients.
Topics: Bacterial Typing Techniques; Drug Resistance, Bacterial; Electrophoresis, Gel, Pulsed-Field; Hospitals, University; Humans; Integrons; Multilocus Sequence Typing; Poland; Pseudomonas Infections; Pseudomonas aeruginosa; beta-Lactamases
PubMed: 28791953
DOI: 10.5604/01.3001.0010.3839 -
Journal of Global Antimicrobial... Jun 2024P. aeruginosa is one of the most metabolically versatile bacteria having the ability to survive in multiple environments through its accessory genome. An important...
OBJECTIVES
P. aeruginosa is one of the most metabolically versatile bacteria having the ability to survive in multiple environments through its accessory genome. An important hallmark of P. aeruginosa is the high level of antibiotic resistance, which often makes eradication difficult and sometimes impossible. Evolutionary forces have led to this bacterium to develop high antimicrobial resistance with a variety of elements contributing to both intrinsic and acquired resistance. The objectives were to genetically and phenotypically characterizer P. aeruginosa strains isolated from companion animals of different species.
METHODS
We characterized a collection of 39 P. aeruginosa strains isolated from infected animals. The genetic characterization was in relation to chromosomal profile by PFGE; content of virulence gene; presence of genomic islands (GIs); genes of the cytotoxins exported by T3SS: exoU, exoS, exoT and exoY; and type IV pili allele. The phenotypic characterization was based on patterns of susceptibility to different antimicrobials.
RESULTS
Each strain had a PFGE profile, a high virulence genes content, and a large accessory genome. However, most of the strains presented high sensitivity to almost all antimicrobials tested, showing no acquired resistance (no β-lactamases). The exception to this lack of resistance was seen with penicillin.
CONCLUSIONS
P. aeruginosa could be a naturally sensitive bacterium to standard antimicrobials but could rapidly develop intrinsic and acquired resistance when the bacterium is exposed to pressure exerted by antibiotics, as observed in hospital settings.
Topics: Pseudomonas aeruginosa; Animals; Pseudomonas Infections; Anti-Bacterial Agents; Virulence Factors; Microbial Sensitivity Tests; Genomic Islands; Virulence; Drug Resistance, Multiple, Bacterial
PubMed: 38452900
DOI: 10.1016/j.jgar.2024.02.023 -
Revista Da Sociedade Brasileira de... 2015Chamomile (Chamaemelum nobile) is widely used throughout the world, and has anti-inflammatory, deodorant, bacteriostatic, antimicrobial, carminative, sedative,...
INTRODUCTION
Chamomile (Chamaemelum nobile) is widely used throughout the world, and has anti-inflammatory, deodorant, bacteriostatic, antimicrobial, carminative, sedative, antiseptic, anti-catarrhal, and spasmolytic properties. Because of the increasing incidence of drug-resistant bacteria, the development of natural antibacterial sources such as medical herbs for the treatment of infectious diseases is necessary. Extracts from different plant parts such as the leaves, flowers, fruit, and bark of Combretum albiflorum, Laurus nobilis , and Sonchus oleraceus were found to possess anti-quorum sensing (QS) activities. In this study, we evaluated the effect of C. nobile against Pseudomonas aeruginosa biofilm formation.
METHODS
The P. aeruginosa samples were isolated from patients with different types of infection, including wound infection, septicemia, and urinary tract infection. The flowers of C. nobile were dried and the extract was removed using a rotary device and then dissolved in dimethyl sulfoxide at pH 7.4. The microdilution method was used to evaluate the minimum inhibitory concentration (MIC) of this extract on P. aeruginosa , and biofilm inhibition was assayed.
RESULTS
Eighty percent of the isolated samples (16/20) could form a biofilm, and most of these were isolated from wound infections. The biofilm inhibitory concentration of the C. nobile extract was 6.25-25mg/ml, whereas the MIC was 12.5-50mg/ml.
CONCLUSIONS
The anti-QS property of C. nobile may play an important role in its antibacterial activity, thus offering an additional strategy in the fight against bacterial infections. However, molecular investigation is required to explore the exact mechanisms of the antibacterial action and functions of this phytocompound.
Topics: Anti-Bacterial Agents; Biofilms; Chamaemelum; Humans; Microbial Sensitivity Tests; Plant Extracts; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 26312934
DOI: 10.1590/0037-8682-0065-2015 -
Microbial Genomics Mar 2021is one of the main microbial species colonizing the lungs of cystic fibrosis patients and is responsible for the decline in respiratory function. Despite the hostile... (Review)
Review
is one of the main microbial species colonizing the lungs of cystic fibrosis patients and is responsible for the decline in respiratory function. Despite the hostile pulmonary environment, is able to establish chronic infections thanks to its strong adaptive capacity. Various longitudinal studies have attempted to compare the strains of early infection with the adapted strains of chronic infection. Thanks to new '-omics' techniques, convergent genetic mutations, as well as transcriptomic and proteomic dysregulations have been identified. As a consequence of this evolution, the adapted strains of have particular phenotypes that promote persistent infection.
Topics: Adaptation, Physiological; Animals; Cystic Fibrosis; Genotype; Humans; Phenotype; Pseudomonas Infections; Pseudomonas aeruginosa
PubMed: 33529147
DOI: 10.1099/mgen.0.000513 -
Microbes and Environments 2010Genetic typing of Pseudomonas aeruginosa isolated from the open ocean has revealed that marine strains form unique clusters. To clarify whether this genetic variation...
Genetic typing of Pseudomonas aeruginosa isolated from the open ocean has revealed that marine strains form unique clusters. To clarify whether this genetic variation reflects differences in pattern of culturability and survival, a marine strain was compared with a freshwater strain and a clinical strain in microcosms with different levels of NaCl (0 to 7% [w/v]), pH (4.0 to 9.0) and temperature (-20, 0, 4, 25 and 37°C) in both artificial seawater (ASW) and distilled water (DW). The viable but non-culturable (VBNC) state of P. aeruginosa was also monitored. The marine strain 1200 grew better at high NaCl and pH, whereas the freshwater strain 1030 did better at 0 to 3% NaCl and a pH of less than 7.0. The clinical strain 1564 grew best at neutral pH and 0% NaCl. No significant differences were observed among the strains in culturability at different temperatures. Like other bacteria, P. aeruginosa enters a VBNC state under stressful conditions. The marine P. aeruginosa isolate exhibits a unique pattern of culturability and survival which demonstrates a physiological adaptation to the ocean environment.
Topics: Fresh Water; Humans; Microbial Viability; Pseudomonas Infections; Pseudomonas aeruginosa; Seawater; Sodium Chloride
PubMed: 21576881
DOI: 10.1264/jsme2.me09178 -
PloS One 2020Pseudomonas aeruginosa is an opportunistic pathogen causing different types of infections, particularly in intensive care unit patients. Characteristics that favor its...
Pseudomonas aeruginosa is an opportunistic pathogen causing different types of infections, particularly in intensive care unit patients. Characteristics that favor its persistence artificial environments are related to its high adaptability, wide arsenal of virulence factors and resistance to several antimicrobial classes. Among the several virulence determinants, T3SS stands as the most important due to the clinical impact of exoS and exoU genes in patient's outcome. The molecular characterization of P. aeruginosa isolates helps in the comprehension of transmission dynamics and enhance knowledge of virulence and resistance roles in infection process. In the present study, we investigated virulence and resistance properties and the genetic background of P. aeruginosa isolated from ICUs patients at a referral hospital in Brazilian Amazon. A total of 54 P. aeruginosa isolates were characterized by detecting 19 virulence-related genes, antimicrobial susceptibility testing, molecular detection of β-lactamase-encoding genes and genotyping by MLST and rep-PCR. Our findings showed high prevalence of virulence-related markers, where 53.7% of the isolates presented at least 17 genes among the 19 investigated (P = 0.01). The rare exoS+/exoU+ cytotoxic virulotype was detected in 55.6% of isolates. Antimicrobial susceptibility testing revealed percentages of antibiotic resistance above 50% to carbapenems, cephalosporins and fluoroquinolones associated to MDR/XDR isolates. Isolates harboring both blaSPM-1 and blaOXA genes were also detected. Genotyping methods demonstrated a wide genetic diversity of strains spread among the different intensive care units, circulation of international MDR/XDR high-risk clones (ST111, ST235, ST244 and ST277) and emergence of seven novel MLST lineages. Finally, our findings highlight the circulation of strains with high virulence potential and resistance to antimicrobials and may be useful on comprehension of pathogenicity process, treatment guidance and establishment of strategies to control the spread of epidemic P. aeruginosa strains.
Topics: Brazil; Genetic Variation; Hospitals; Humans; Molecular Typing; Prevalence; Pseudomonas aeruginosa; Referral and Consultation; Virulence
PubMed: 32911510
DOI: 10.1371/journal.pone.0238741