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Microbiology Spectrum Dec 2021Mobbing, group attack of prey on predator, is a behavior seen in many animal species in which prey animals use numbers and coordination to counter individually superior...
Mobbing, group attack of prey on predator, is a behavior seen in many animal species in which prey animals use numbers and coordination to counter individually superior predators. We studied attack behavior of Pseudomonas aeruginosa toward the bacterivore Acanthamoeba castellanii. This behavior consists of directed motility toward and specific adhesion to the predator cells, enacted in seconds and responding to both prey and predator population densities. Attack coordination relies on remote sensing of the predator and the use of the Pseudomonas quinolone signal (PQS), a P. aeruginosa species-specific quorum sensing molecule. Mutants unable to produce the PQS show unspecific adhesion and reduced survival, and a corresponding increase in predator population occurs as a result of predation. The addition of an external PQS restored some predator-specific adherence within seconds, suggesting a novel response mechanism to this quorum sensing (QS) signal. Fast behavioral response of P. aeruginosa to PQS is also supported by the rate of signal accumulation in the culture, reaching relevant concentrations within minutes, enabling bacteria response to self population density in these short timescales. These results portray a well-regulated group attack of the bacteria against their predator, reacting within seconds to environmental cues and species-specific signaling, which is analogous in many ways to animal mobbing behavior. Pseudomonas aeruginosa was shown previously to attack amoebae and other predators by adhering to them and injecting them with virulent substances. In this work, we show that an active, coordinated group behavior is enacted by the bacteria to utilize these molecular components, responding to both predator and bacterial population density. In addition to their ecological significance, immediate behavioral changes observed in response to PQS suggest the existence of a fast QS signal cascade, which is different from canonical QS that relies on slow-to-respond gene regulation. Similar regulatory circuits may drive other bacterial adaptations and pathogenicity mechanisms and may have important clinical implications.
Topics: Acanthamoeba castellanii; Bacterial Adhesion; Host-Pathogen Interactions; Kinetics; Population Dynamics; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 34851177
DOI: 10.1128/Spectrum.00642-21 -
International Journal of Molecular... Mar 2020Natural products play vital roles against infectious diseases since ancient times and most drugs in use today are derived from natural sources. Worldwide, multi-drug...
Natural products play vital roles against infectious diseases since ancient times and most drugs in use today are derived from natural sources. Worldwide, multi-drug resistance becomes a massive threat to the society with increasing mortality. Hence, it is very crucial to identify alternate strategies to control these 'super bugs'. is an opportunistic pathogen reported to be resistant to a large number of critically important antibiotics. Quorum sensing (QS) is a cell-cell communication mechanism, regulates the biofilm formation and virulence factors that endow pathogenesis in various bacteria including In this study, we identified and evaluated quorum sensing inhibitors (QSIs) from plant-based natural products against . In silico studies revealed that catechin-7-xyloside (C7X), sappanol and butein were capable of interacting with LasR, a LuxR-type quorum sensing regulator of . In vitro assays suggested that these QSIs significantly reduced the biofilm formation, pyocyanin, elastase, and rhamnolipid without influencing the growth. Especially, butein reduced the biofilm formation up to 72.45% at 100 µM concentration while C7X and sappanol inhibited the biofilm up to 66% and 54.26% respectively. Microscale thermophoresis analysis revealed that C7X had potential interaction with LasR ( = 933±369 nM) and thermal shift assay further confirmed the biomolecular interactions. These results suggested that QSIs are able to substantially obstruct the QS. Since LuxR-type transcriptional regulator homologues are present in numerous bacterial species, these QSIs may be developed as broad spectrum anti-infectives in the future.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Biofilms; Biological Products; Humans; Molecular Docking Simulation; Pseudomonas Infections; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 32235775
DOI: 10.3390/ijms21062190 -
Infection, Genetics and Evolution :... Nov 2019Pseudomonas aeruginosa (PA) is an opportunistic pathogen that produces widespread and often overwhelming infections. Among different virulence factors, toxins are... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Pseudomonas aeruginosa (PA) is an opportunistic pathogen that produces widespread and often overwhelming infections. Among different virulence factors, toxins are important bacterial agent which increases PA pathogenesis especially in immunocompromised patients. The aim of this meta-analysis was to determine the prevalence of exotoxin production in PA isolates in the world. Also according to the importance of drug resistance in isolates with more pathogenicity this estimation was conducted in resistant isolates.
METHODS
A systematic search was conducted in international database like PubMed, Scopus, Web of Science and Embase up to December 2018. Joanna Briggs Institute Checklist was used to evaluate the quality assessment of studies. Random effect model was applied to pool the prevalence data. Stata 13 software was used to analyze the data.
RESULTS
Total of 58 eligible studies that fulfilled the inclusion criteria of the study were selected for qualitative synthesis. Among exotoxins; the highest prevalence was related to exoT (0.83 (CI95%: 0.64-0.96)). Lowest prevalence rate was seen in exoU with estimated prevalence 0.32 (CI95%: 0.24-0.41). In Carbapenem resistance isolates exoA and exoT had the highest prevalence (1.00 (CI95%: 0.98-1.00)).
CONCLUSION
This first meta-analysis on PA isolates with toxin potency indicated high prevalence of exotoxin production in clinical isolates of PA which is an alarming point as a clinical aspect. It was found that the ExoT has the most prevalence rate among toxins. The results of simultaneous evaluation of exotoxins and antimicrobial resistance can develop treatment policies against PA infections in hospitals and hospitalized patients.
Topics: Bacterial Toxins; Cross Infection; Exotoxins; Humans; Prevalence; Pseudomonas Infections; Pseudomonas aeruginosa; Virulence Factors
PubMed: 31518698
DOI: 10.1016/j.meegid.2019.104037 -
Medecine Et Maladies Infectieuses Sep 2020The Carba NP test is a biochemical chromogenic assay developed to detect carbapenemase activity. Variable performance has been reported according to the type of... (Review)
Review
INTRODUCTION
The Carba NP test is a biochemical chromogenic assay developed to detect carbapenemase activity. Variable performance has been reported according to the type of carbapenemase and bacterial species involved. We aimed to describe the benefit of the Carba NP test and its commercial version, the RAPIDEC® CARBA NP, to detect carbapenemase-producing Pseudomonas aeruginosa.
METHODS
PubMed and ScienceDirect databases were searched. The following data was collected from each included study: research protocol, molecular profile of the tested strains, and sensitivity and specificity of the test used to detect carbapenemase-producing P. aeruginosa.
RESULTS
Thirty-four studies were included. The most frequently tested strains were metallo-beta-lactamase producers. The pooled sensitivity to detect carbapenemase-producing P. aeruginosa with the original Carba NP test, the Clinical and Laboratory Standards Institute (CLSI) Carba NP test, and the RAPIDEC® CARBA NP was 92%, 95%, and 96%, respectively. The pooled specificity was 99% with the original and the CLSI Carba NP tests, and 92% with the RAPIDEC® CARBA NP. Several studies evaluated modified versions of the Carba NP test to detect carbapenemase-producing P. aeruginosa, with reported sensitivity and specificity exceeding 90% in most cases.
CONCLUSION
The Carba NP test allows for fast screening and easy handling as well as optimal performance to detect carbapenemase-producing P. aeruginosa. These findings should be confirmed by further studies including a larger cohort of isolates and various types of carbapenemases, mainly non-metallo-beta-lactamases.
Topics: Bacterial Proteins; Bacteriological Techniques; Humans; Pseudomonas aeruginosa; beta-Lactamases
PubMed: 31899068
DOI: 10.1016/j.medmal.2019.12.002 -
Expert Review of Anti-infective Therapy Jun 2020: is a common, ubiquitous bacterium that is found in natural environments but is also a successful opportunistic pathogen of humans and plants. The reasons for this... (Review)
Review
: is a common, ubiquitous bacterium that is found in natural environments but is also a successful opportunistic pathogen of humans and plants. The reasons for this flexibility and evolutionary success can be attributed to its ability to readily acquire new genes to ensure its survival enabling it to survive desiccation, the action of antimicrobial compounds and invade new territories such as modern hospitals with high levels of antibiotic usage.: Literature was searched using PubMed and Web of science (05/19 to 05/20). Identified studies paint a picture of a dynamic, highly variable population shaped by frequent intra- and inter-species horizontal gene transfer resulting in a species able to resist the action of antibiotics and deploy multiple virulence strategies controlled by complex quorum-sensing systems. We investigate possible control measures including anti-virulence and environmental control measures.: is a resilient, richly diverse species but also a global health threat due to the emergence and global dissemination of successful multiresistant clones that resist all antibiotics. Genomics offers the potential for rapid identification of 'high-risk' clones to guide chemotherapy, but novel control measures are also required to slow the species progression to pan-resistance.
Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Gene Transfer, Horizontal; Humans; Pseudomonas Infections; Pseudomonas aeruginosa; Quorum Sensing; Virulence
PubMed: 32249619
DOI: 10.1080/14787210.2020.1751610 -
Biologicals : Journal of the... Jan 2020Pseudomonas aeruginosa is Gram-negative bacterium, one of the leading cause of drug-resistant nosocomial infections in developing countries. This bacterium possesses...
Pseudomonas aeruginosa is Gram-negative bacterium, one of the leading cause of drug-resistant nosocomial infections in developing countries. This bacterium possesses chromosomally encoded efflux pumps, poor permeability of outer-membrane and high tendency for biofilm formation which are tools to confer resistance. Bacteriophages are regarded as feasible treatment option for control of resistant P. aeruginosa. The aim of the current study was isolate and characterized a bacteriophage against P. aeruginosa with MDR and biofilm ability. A bacteriophage MA-1 with moderate host range was isolated from waste water. The phage was considerable heat and pH stable. Electron microscopy revealed that phage MA-1 belongs to Myoviridae family. Its genome was dsDNA (≈50 kb), coding for eighteen different proteins (ranging from 12 to 250 KDa). P. aeruginosa-2949 log growth phase was significantly reduced by phage MA-1 (2.5 × 10 CFU/ml) as compared to control (without phage). Phage MA-1 also showed significant reductions of 2.0, 2.5 and 3.2 folds in 24, 48, and 74 h old biofilms after 6 h treatment with phage respectively as compared to control. It was concluded from this study that phage MA-1 has capability of killing P. aeruginosa planktonic cells and biofilm, but for complete eradication cocktail will more effective to avoid resistance.
Topics: Biofilms; Drug Resistance, Multiple, Bacterial; Pseudomonas Phages; Pseudomonas aeruginosa
PubMed: 31685418
DOI: 10.1016/j.biologicals.2019.10.003 -
Journal of Infection in Developing... Oct 2019Pseudomonas aeruginosa is an ubiquitous bacterium causes various community-acquired and nosocomial infections. In this investigation, we aimed to screen the antibiotic...
INTRODUCTION
Pseudomonas aeruginosa is an ubiquitous bacterium causes various community-acquired and nosocomial infections. In this investigation, we aimed to screen the antibiotic susceptibility patterns and the prevalence of virulence factor genes in a set of Pseudomonas aeruginosa isolated from nosocomial and community-acquired infections in the Northwestern of Morocco.
METHODOLOGY
A total of 155 of Pseudomonas aeruginosa strains were collected (January 2015 - December 2016) from nosocomial and community-acquired infections at hospital centers and clinical laboratories in the Northwestern of Morocco. Antimicrobial susceptibility test was performed by the standard disk diffusion method. In addition, PCR assays were used for screening five virulence encoding genes (lasB, algD, plcH, exoA, and exoS).
RESULTS
Our results revealed that high level of antimicrobial resistance was detected towards aztreonam (27.1%) followed by meropenem (14.2%). The resistance to imipenem was significantly higher in strains isolated from nosocomial infections (12.7%) than strains isolated from community-acquired infections (1.5%). The results highlighted that lasB (98.7%) and exoS (98.7%) were the most frequent virulence genes.
CONCLUSIONS
This survey provides data about phenotypic and genotypic properties of Pseudomonas aeruginosa emerged in the Northwestern of Morocco. It could be helpful for the health workers to improve infection control measures and to establish a surveillance system.
Topics: Anti-Bacterial Agents; Genes, Bacterial; Humans; Microbial Sensitivity Tests; Morocco; Pseudomonas Infections; Pseudomonas aeruginosa; Virulence; Virulence Factors
PubMed: 32084019
DOI: 10.3855/jidc.10675 -
The FEBS Journal Apr 2021The opportunistic pathogen Pseudomonas aeruginosa, one of the most prevalent species in infections of the cystic fibrosis lung, produces a range of secondary...
The opportunistic pathogen Pseudomonas aeruginosa, one of the most prevalent species in infections of the cystic fibrosis lung, produces a range of secondary metabolites, among them the respiratory toxin 2-heptyl-1-hydroxyquinolin-4(1H)-one (2-heptyl-4-hydroxyquinoline N-oxide, HQNO). Cultures of the emerging cystic fibrosis pathogen Mycobacteroides abscessus detoxify HQNO by methylating the N-hydroxy moiety. In this study, the class I methyltransferase MAB_2834c and its orthologue from Mycobacterium tuberculosis, Rv0560c, were identified as HQNO O-methyltransferases. The P. aeruginosa exoproducts 4-hydroxyquinolin-2(1H)-one (DHQ), 2-heptylquinolin-4(1H)-one (HHQ), and 2-heptyl-3-hydroxyquinolin-4(1H)-one (the 'Pseudomonas quinolone signal', PQS), some structurally related (iso)quinolones, and the flavonol quercetin were also methylated; however, HQNO was by far the preferred substrate. Both enzymes converted a benzimidazole[1,2-a]pyridine-4-carbonitrile-based compound, representing the scaffold of antimycobacterial substances, to an N-methylated derivative. We suggest that these promiscuous methyltransferases, newly termed as heterocyclic toxin methyltransferases (Htm), are involved in cellular response to chemical stress and possibly contribute to resistance of mycobacteria toward antimicrobial natural compounds as well as drugs. Thus, synthetic antimycobacterial agents may be designed to be unamenable to methyl transfer. ENZYMES: S-adenosyl-l-methionine:2-heptyl-1-hydroxyquinolin-4(1H)-one O-methyl-transferase, EC 2.1.1.
Topics: Hydroxyquinolines; Methyltransferases; Mycobacterium; Pseudomonas aeruginosa; Secondary Metabolism
PubMed: 33064871
DOI: 10.1111/febs.15595 -
Canadian Journal of Microbiology Aug 2019is a virulent bacterium that secretes a variety of virulence factors that aid in establishing infections in individuals. Allicin, derived from garlic, has been shown to...
is a virulent bacterium that secretes a variety of virulence factors that aid in establishing infections in individuals. Allicin, derived from garlic, has been shown to inhibit virulence factor production and biofilm formation in . However, the mechanisms underlying the allicin-mediated regulation of virulence remain unclear. In this study, we investigated the possible mechanisms underlying allicin-mediated virulence regulation in . The results showed that allicin attenuates the production of virulence-associated factors, such as elastase, pyocyanin, pyoverdine, and rhamnolipids, by inhibiting the and quorum-sensing systems. Further analysis revealed that the and systems play different roles during the allicin-mediated regulation process. Taken together, these results support the potential use of allicin as a therapeutic agent in controlling infection and associated mechanisms.
Topics: Bacterial Proteins; Disulfides; Gene Expression Regulation, Bacterial; Glycolipids; Pseudomonas aeruginosa; Pyocyanine; Quorum Sensing; Sulfinic Acids; Virulence; Virulence Factors
PubMed: 31009577
DOI: 10.1139/cjm-2019-0055 -
MBio Oct 2021The opportunistic human pathogen Pseudomonas aeruginosa is known for exhibiting diverse forms of collective behaviors, like swarming motility and biofilm formation....
The opportunistic human pathogen Pseudomonas aeruginosa is known for exhibiting diverse forms of collective behaviors, like swarming motility and biofilm formation. Swarming in P. aeruginosa is a collective movement of the bacterial population over a semisolid surface, but specific swarming signals are not clear. We hypothesize that specific environmental signals induce swarming in P. aeruginosa. We show that under nutrient-limiting conditions, a low concentration of ethanol provides a strong ecological motivation for swarming in P. aeruginosa strain PA14. Ethanol serves as a signal and not a source of carbon under these conditions. Moreover, ethanol-driven swarming relies on the ability of the bacteria to metabolize ethanol to acetaldehyde using a periplasmic quinoprotein alcohol dehydrogenase, ExaA. We found that ErdR, an orphan response regulator linked to ethanol oxidation, is necessary for the transcriptional regulation of a cluster of 17 genes, including , during swarm lag. Further, we show that P. aeruginosa displays characteristic foraging motility on a lawn of Cryptococcus neoformans, a yeast species, in a manner dependent on the ethanol dehydrogenase ErdR and on rhamnolipids. Finally, we show that ethanol, as a volatile, could induce swarming in P. aeruginosa at a distance, suggesting long-range spatial effects of ethanol as a signaling molecule. P. aeruginosa, a Gram-negative opportunistic pathogen, can adapt to diverse ecological niches and exhibits several forms of social behavior. Swarming (flagellum-driven collective motility) is a collective behavior of P. aeruginosa exclusively over semisolid surfaces. However, the ecological motivations for swarming are not known. Here, we demonstrate the importance of a specific environmental cue, ethanol, produced by many microbes, in inducing swarming in the P. aeruginosa population during starvation. We show that ethanol is a signal for swarming in P. aeruginosa. Our study provides a framework to understand swarming as a chemotactic response of bacterium to a food source via a foraging signal, ethanol.
Topics: Bacterial Proteins; Carbon; Ethanol; Flagella; Gene Expression Regulation, Bacterial; Pseudomonas aeruginosa
PubMed: 34607460
DOI: 10.1128/mBio.02033-21