-
Toxins Sep 2020is the most common human opportunistic pathogen associated with nosocomial diseases. In 2017, the World Health Organization has classified as a critical agent... (Review)
Review
is the most common human opportunistic pathogen associated with nosocomial diseases. In 2017, the World Health Organization has classified as a critical agent threatening human health, and for which the development of new treatments is urgently necessary. One interesting avenue is to target virulence factors to understand pathogenicity. Thus, characterising exoproteins of is a hot research topic and proteomics is a powerful approach that provides important information to gain insights on bacterial virulence. The aim of this review is to focus on the contribution of proteomics to the studies of exoproteins, highlighting its relevance in the discovery of virulence factors, post-translational modifications on exoproteins and host-pathogen relationships.
Topics: Bacterial Proteins; Host-Pathogen Interactions; Protein Processing, Post-Translational; Proteome; Proteomics; Pseudomonas aeruginosa; Virulence; Virulence Factors
PubMed: 32899849
DOI: 10.3390/toxins12090571 -
Current Opinion in Microbiology Feb 2018Pseudomonas aeruginosa acute and chronic infections are of great concern to human health, especially in hospital settings. It is currently assumed that P. aeruginosa has... (Review)
Review
Pseudomonas aeruginosa acute and chronic infections are of great concern to human health, especially in hospital settings. It is currently assumed that P. aeruginosa has two antagonistic pathogenic strategies that parallel two different lifestyles; free-living cells are predominantly cytotoxic and induce an acute inflammatory reaction, while biofilm-forming communities cause refractory chronic infections. Recent findings suggest that the planktonic-to-sessile transition is a complex, reversible and overall dynamic differentiation process. Here, we examine how the Gac/Rsm regulatory cascade, a key player in this lifestyle switch, endows P. aeruginosa with both a permissive lifecycle in nature and flexible virulence strategy during infection.
Topics: Animals; Bacterial Infections; Bacterial Proteins; Biofilms; Gene Expression Regulation, Bacterial; Host-Pathogen Interactions; Humans; Mice; Pseudomonas aeruginosa; Virulence; Virulence Factors
PubMed: 29166621
DOI: 10.1016/j.mib.2017.11.006 -
Current Opinion in Microbiology Feb 2020Chronic infections often contain complex polymicrobial communities that are recalcitrant to antibiotic treatment. The pathogens associated with these infectious... (Review)
Review
Chronic infections often contain complex polymicrobial communities that are recalcitrant to antibiotic treatment. The pathogens associated with these infectious communities are often studied in pure culture for their ability to cause disease. However, recent studies have begun to focus on the role of polymicrobial interactions in disease outcomes. Pseudomonas aeruginosa can colonize patients with chronic lung diseases for years and sometimes even decades. During these prolonged infections, P. aeruginosa encounters a plethora of other microbes including bacteria, fungi, and viruses. The interactions between these microbes can vary greatly, ranging from antagonistic to synergistic depending on specific host and microbe-associated contexts. These additional layers of complexity associated with chronic P. aeruginosa infections must be considered in future studies in order to fully understand the physiology of infection. Such studies focusing on the entire infectious community rather than individual species may ultimately lead to more effective therapeutic design for persistent polymicrobial infections.
Topics: Animals; Bacteria; Humans; Lung; Lung Diseases; Microbial Interactions; Microbiota; Pseudomonas aeruginosa
PubMed: 32062024
DOI: 10.1016/j.mib.2020.01.014 -
Clinical Microbiology and Infection :... Mar 2020Pseudomonas aeruginosa is one of the most common pathogens isolated from respiratory tract specimen in patients with bronchiectasis. It is considered highly responsible... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Pseudomonas aeruginosa is one of the most common pathogens isolated from respiratory tract specimen in patients with bronchiectasis. It is considered highly responsible for pathogenicity, progression and clinical outcomes of bronchiectasis.
AIMS
To summarize existing evidence on how different factors of Pseudomonas aeruginosa affect the pathogenicity, progression and clinical outcomes of bronchiectasis, so as to provide possible insights for clinical practice and related research in the future.
SOURCES
PubMed was searched for studies pertaining to bronchiectasis and P. aeruginosa published to date, with no specific inclusion or exclusion criteria. Reference lists of retrieved reviews were searched for additional articles.
CONTENT
This review focused on non-cystic fibrosis bronchiectasis and also provided some data on cystic fibrosis when studies in bronchiectasis were limited. We discussed various factors in relation to P. aeruginosa: virulence factors, drug resistance, regulatory systems, genomic diversity and transmission of P. aeruginosa, as well as treatment for P. aeruginosa. Their impacts on bronchiectasis and its management were discussed.
IMPLICATIONS
The impact of P. aeruginosa on bronchiectasis is definite, although conclusions in some aspects are still vague. Faced with the worrying drug-resistance status and treatment bottleneck, individualized management and novel therapies beyond the classic pathway are most likely to be a future trend. To confirm the independent or integrated impact of various factors of P. aeruginosa on bronchiectasis and to figure out all the problems mentioned, larger randomized control trials are truly needed in the future.
Topics: Anti-Bacterial Agents; Bronchiectasis; Clinical Decision-Making; Disease Management; Disease Progression; Disease Susceptibility; Drug Resistance, Bacterial; Genetic Variation; Genome, Bacterial; Humans; Patient Outcome Assessment; Pseudomonas Infections; Pseudomonas aeruginosa; Virulence Factors
PubMed: 31306794
DOI: 10.1016/j.cmi.2019.07.010 -
Pathogens and Disease Mar 2015Pseudomonas aeruginosa is one of the most intractable human pathogens that pose serious clinical challenge due to extensive prevalence of multidrug-resistant clinical... (Review)
Review
Pseudomonas aeruginosa is one of the most intractable human pathogens that pose serious clinical challenge due to extensive prevalence of multidrug-resistant clinical isolates. Armed with abundant virulence and antibiotic resistance mechanisms, it is a major etiologic agent in a number of acute and chronic infections. A complex and intricate network of regulators dictates the expression of pathogenicity factors in P. aeruginosa. Some proteins within the network play key roles and control multiple pathways. This review discusses the role of one such protein, AmpR, which was initially recognized for its role in antibiotic resistance by regulating AmpC β-lactamase. Recent genomic, proteomic and phenotypic analyses demonstrate that AmpR regulates expression of hundreds of genes that are involved in diverse pathways such as β-lactam and non-β-lactam resistance, quorum sensing and associated virulence phenotypes, protein phosphorylation, and physiological processes. Finally, ampR mutations in clinical isolates are reviewed to shed light on important residues required for its function in antibiotic resistance. The prevalence and evolutionary implications of AmpR in pathogenic and nonpathogenic proteobacteria are also discussed. A comprehensive understanding of proteins at nodal positions in the P. aeruginosa regulatory network is crucial in understanding, and ultimately targeting, the pathogenic stratagems of this organism.
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Gene Regulatory Networks; Pseudomonas aeruginosa; Regulon
PubMed: 25066236
DOI: 10.1111/2049-632X.12208 -
Journal of Bacteriology Jan 2016The formation of the organized bacterial community called biofilm is a crucial event in bacterial physiology. Given that biofilms are often refractory to antibiotics and... (Review)
Review
The formation of the organized bacterial community called biofilm is a crucial event in bacterial physiology. Given that biofilms are often refractory to antibiotics and disinfectants to which planktonic bacteria are susceptible, their formation is also an industrially and medically relevant issue. Pseudomonas aeruginosa, a well-known human pathogen causing acute and chronic infections, is considered a model organism to study biofilms. A large number of environmental cues control biofilm dynamics in bacterial cells. In particular, the dispersal of individual cells from the biofilm requires metabolic and morphological reprogramming in which the second messenger bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) plays a central role. The diatomic gas nitric oxide (NO), a well-known signaling molecule in both prokaryotes and eukaryotes, is able to induce the dispersal of P. aeruginosa and other bacterial biofilms by lowering c-di-GMP levels. In this review, we summarize the current knowledge on the molecular mechanisms connecting NO sensing to the activation of c-di-GMP-specific phosphodiesterases in P. aeruginosa, ultimately leading to c-di-GMP decrease and biofilm dispersal.
Topics: Biofilms; Gene Expression Regulation, Bacterial; Nitric Oxide; Pseudomonas aeruginosa; Signal Transduction
PubMed: 26260455
DOI: 10.1128/JB.00371-15 -
Frontiers in Cellular and Infection... 2016Pseudomonas aeruginosa is an opportunistic pathogen responsible for many diseases such as chronic lung colonization in cystic fibrosis patients and acute infections in... (Review)
Review
Pseudomonas aeruginosa is an opportunistic pathogen responsible for many diseases such as chronic lung colonization in cystic fibrosis patients and acute infections in hospitals. The capacity of P. aeruginosa to be pathogenic toward several hosts is notably due to different secretion systems. Amongst them, P. aeruginosa encodes three Type Six Secretion Systems (T6SS), named H1- to H3-T6SS, that act against either prokaryotes and/or eukaryotic cells. They are independent from each other and inject diverse toxins that interact with different components in the host cell. Here we summarize the roles of these T6SSs in the PAO1 strain, as well as the toxins injected and their targets. While H1-T6SS is only involved in antiprokaryotic activity through at least seven different toxins, H2-T6SS and H3-T6SS are also able to target prokaryotic as well as eukaryotic cells. Moreover, recent studies proposed that H2- and H3-T6SS have a role in epithelial cells invasion by injecting at least three different toxins. The diversity of T6SS effectors is astounding and other effectors still remain to be discovered. In this review, we present a table with other putative P. aeruginosa strain PAO1 T6SS-dependent effectors. Altogether, the T6SSs of P. aeruginosa are important systems that help fight other bacteria for their ecological niche, and are important in the pathogenicity process.
Topics: Antibiosis; Bacterial Toxins; Protein Transport; Pseudomonas aeruginosa; Type VI Secretion Systems; Virulence; Virulence Factors
PubMed: 27376031
DOI: 10.3389/fcimb.2016.00061 -
Scientific Reports Aug 2021The effect of nanobubbles on anaerobic growth and metabolism of Pseudomonas aeruginosa was investigated. P. aeruginosa grew earlier in the culture medium containing...
The effect of nanobubbles on anaerobic growth and metabolism of Pseudomonas aeruginosa was investigated. P. aeruginosa grew earlier in the culture medium containing nanobubbles and the bacterial cell concentration in that culture medium was increased a few times higher compared to the medium without nanobubbles under anaerobic condition. Both gas and protein, which are the metabolites of P. aeruginosa, were remarkably produced in the culture medium containing nanobubbles whereas those metabolites were little detected in the medium without nanobubbles, indicating nanobubbles activated anaerobic growth and metabolism of P. aeruginosa. The carbon dioxide nanobubbles came to be positively charged by adsorbing cations and delivered ferrous ions, one of the trace essential elements for bacterial growth, to the microbial cells, which activated the growth and metabolism of P. aeruginosa. The oxygen nanobubbles activated the activities of P. aeruginosa as an oxygen source.
Topics: Anaerobiosis; Culture Media; Nanoparticles; Pseudomonas aeruginosa; Sterilization
PubMed: 34413439
DOI: 10.1038/s41598-021-96503-4 -
Journal of Microbiology and... Jun 2017A biofilm is a community of microbes that typically inhabit on surfaces and are encased in an extracellular matrix. Biofilms display very dissimilar characteristics to... (Review)
Review
A biofilm is a community of microbes that typically inhabit on surfaces and are encased in an extracellular matrix. Biofilms display very dissimilar characteristics to their planktonic counterparts. Biofilms are ubiquitous in the environment and influence our lives tremendously in both positive and negative ways. is a bacterium known to produce robust biofilms. biofilms cause severe problems in immunocompromised patients, including those with cystic fibrosis or wound infection. Moreover, the unique biofilm properties further complicate the eradication of the biofilm infection, leading to the development of chronic infections. In this review, we discuss the history of biofilm research and general characteristics of bacterial biofilms. Then, distinct features pertaining to each stage of biofilm development are highlighted. Furthermore, infections caused by biofilms on their own or in association with other bacterial species (, multispecies biofilms) are discussed in detail.
Topics: Biofilms; Coinfection; Cystic Fibrosis; Genetic Fitness; Humans; Pseudomonas Infections; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 28301918
DOI: 10.4014/jmb.1611.11056 -
Emerging Microbes & Infections Dec 2021Biofilm formation and the appearance of persister cells with low metabolic rates are key factors affecting conventional treatment failure and antibiotic resistance....
Biofilm formation and the appearance of persister cells with low metabolic rates are key factors affecting conventional treatment failure and antibiotic resistance. Using impedance-based measurements, crystal violet staining and traditional culture we have studied the biofilm growth dynamics of 13 strains under the effect of seven conventional antibiotics. Real-time growth quantifications revealed that the exposure of established biofilms to certain concentrations of ciprofloxacin, ceftazidime and tobramycin induced the emergence of persister cells, that showed different morphology and pigmentation, as well increased antibiotic resistance. Whole-genome sequencing of wildtype and persister cells identified several SNPs, a genomic inversion and a genomic duplication in one of the strains. However, these mutations were not uniquely associated with persisters, suggesting that the persistent phenotype may be related to metabolic and transcriptional changes. Given that mannitol has been proposed to activate bacterial metabolism, the synergistic combination of mannitol and ciprofloxacin was evaluated on clinical 48 h biofilms. When administered at doses ≥320 mg/L, mannitol was capable of preventing persister cell formation by efficiently activating dormant bacteria and making them susceptible to the antibiotic. These results were confirmed using viable colony counting. As the tested ciprofloxacin-mannitol combination appeared to fully eradicate mature biofilms, we conclude that impedance-based biofilm diagnostics, which permits antibiotic susceptibility testing and the identification of persister cells, is of great potential for the clinical practice and could aid in establishing treatment breakpoints for emerging biofilm-related infections.
Topics: Anti-Bacterial Agents; Biofilms; Ciprofloxacin; Humans; Microbial Sensitivity Tests; Microbial Viability; Mutation; Polymorphism, Single Nucleotide; Pseudomonas Infections; Pseudomonas aeruginosa; Staining and Labeling
PubMed: 34663186
DOI: 10.1080/22221751.2021.1994355