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Scientific Reports Aug 2015Pseudomonas aeruginosa is a ubiquitous environmental bacterium and a clinically significant opportunistic human pathogen. Central to the ability of P. aeruginosa to...
Pseudomonas aeruginosa is a ubiquitous environmental bacterium and a clinically significant opportunistic human pathogen. Central to the ability of P. aeruginosa to colonise both environmental and host niches is the acquisition of zinc. Here we show that P. aeruginosa PAO1 acquires zinc via an ATP-binding cassette (ABC) permease in which ZnuA is the high affinity, zinc-specific binding protein. Zinc uptake in Gram-negative organisms predominantly occurs via an ABC permease, and consistent with this expectation a P. aeruginosa ΔznuA mutant strain showed an ~60% reduction in cellular zinc accumulation, while other metal ions were essentially unaffected. Despite the major reduction in zinc accumulation, minimal phenotypic differences were observed between the wild-type and ΔznuA mutant strains. However, the effect of zinc limitation on the transcriptome of P. aeruginosa PAO1 revealed significant changes in gene expression that enable adaptation to low-zinc conditions. Genes significantly up-regulated included non-zinc-requiring paralogs of zinc-dependent proteins and a number of novel import pathways associated with zinc acquisition. Collectively, this study provides new insight into the acquisition of zinc by P. aeruginosa PAO1, revealing a hitherto unrecognized complexity in zinc homeostasis that enables the bacterium to survive under zinc limitation.
Topics: Amino Acid Motifs; Amino Acid Sequence; Bacterial Proteins; Computational Biology; Down-Regulation; Gene Expression Regulation, Bacterial; Homeostasis; Membrane Transport Proteins; Models, Biological; Molecular Sequence Data; Pseudomonas aeruginosa; Ribosomal Proteins; Sequence Homology, Amino Acid; Substrate Specificity; Transcription, Genetic; Transition Temperature; Up-Regulation; Zinc
PubMed: 26290475
DOI: 10.1038/srep13139 -
BMC Biochemistry Mar 2016Pseudomonas aeruginosa, a Gram-negative, aerobic coccobacillus bacterium is an opportunistic human pathogen and worldwide the fourth most common cause of...
BACKGROUND
Pseudomonas aeruginosa, a Gram-negative, aerobic coccobacillus bacterium is an opportunistic human pathogen and worldwide the fourth most common cause of hospital-acquired infections which are often high mortality such as ventilator-associated pneumoniae. The polyamine metabolism of P. aeruginosa and particularly the deacetylation of acetylpolyamines has been little studied up to now. Results with other bacterial pathogens e.g., Y. pestis suggest that polyamines may be involved in the formation of biofilms or confer resistance against certain antibiotics.
RESULTS
To elucidate the role of acetylpolyamines and their enzymatic deacetylation in more detail, all three putative acetylpolyamine amidohydrolases (APAHs) from P. aeruginosa have been expressed in enzymatic active form. The APAHs PA0321 and PA1409 are shown to be true polyamine deacetylases, whereas PA3774 is not able to deacetylate acetylated polyamines. Every APAH can hydrolyze trifluoroacetylated lysine-derivatives, but only PA1409 and much more efficiently PA3774 can also process the plain acetylated lysine substrate. P. aeruginosa is able to utilize acetylcadaverine and acetylputrescine as a carbon source under glucose starvation. If either the PA0321 or the PA1409 but not the PA3774 gene is disrupted, the growth of P. aeruginosa is reduced and delayed. In addition, we were able to show that the APAH inhibitors SAHA and SATFMK induce biofilm formation in both PA14 and PAO1 wildtype strains.
CONCLUSIONS
P. aeruginosa has two functional APAHs, PA0321 and PA1409 which enable the utilization of acetylpolyamines for the metabolism of P. aeruginosa. In contrast, the physiological role of the predicted APAH, PA3774, remains to be elucidated. Its ability to deacetylate synthetic acetylated lysine substrates points to a protein deacetylation functionality with yet unknown substrates.
Topics: Amino Acid Sequence; Aminohydrolases; Biofilms; Histone Deacetylase 6; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Molecular Sequence Data; Pseudomonas aeruginosa; Sequence Alignment; Substrate Specificity
PubMed: 26956223
DOI: 10.1186/s12858-016-0063-z -
Pseudomonas aeruginosa Mutant Is Defective in Biofilm Formation, Swarming, and Pyocyanin Production.MSphere Apr 2018is a ubiquitous Gram-negative bacterium that can cause severe opportunistic infections. The principal redox buffer employed by this organism is glutathione (GSH). To...
is a ubiquitous Gram-negative bacterium that can cause severe opportunistic infections. The principal redox buffer employed by this organism is glutathione (GSH). To assess the role of GSH in the virulence of , a number of analyses were performed using a mutant strain deficient in , which does not produce GSH. The mutant strain exhibited a growth delay in minimal medium compared to the wild-type strain. Furthermore, the mutant was defective in biofilm and persister cell formation and in swimming and swarming motility and produced reduced levels of pyocyanin, a key virulence factor. Finally, the mutant strain demonstrated increased sensitivity to methyl viologen (a redox cycling agent) as well as the thiol-reactive antibiotics fosfomycin and rifampin. Taken together, these data suggest a key role for GSH in the virulence of is a ubiquitous bacterium that can cause severe opportunistic infections, including many hospital-acquired infections. It is also a major cause of infections in patients with cystic fibrosis. is intrinsically resistant to a number of drugs and is capable of forming biofilms that are difficult to eradicate with antibiotics. The number of drug-resistant strains is also increasing, making treatment of infections very difficult. Thus, there is an urgent need to understand how causes disease in order to find novel ways to treat infections. We show that the principal redox buffer, glutathione (GSH), is involved in intrinsic resistance to the fosfomycin and rifampin antibiotics. We further demonstrate that GSH plays a role in disease and infection, since a mutant lacking GSH has less biofilm formation, is less able to swarm, and produces less pyocyanin, a pigment associated with infection.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Biofilms; Drug Resistance, Multiple, Bacterial; Fosfomycin; Glutathione; Mutation; Paraquat; Pseudomonas aeruginosa; Pyocyanine; Rifampin; Virulence; Virulence Factors
PubMed: 29669887
DOI: 10.1128/mSphere.00155-18 -
Nature Communications Jul 2021R-bodies are long, extendable protein polymers formed in the cytoplasm of some bacteria; they are best known for their role in killing of paramecia by bacterial...
R-bodies are long, extendable protein polymers formed in the cytoplasm of some bacteria; they are best known for their role in killing of paramecia by bacterial endosymbionts. Pseudomonas aeruginosa PA14, an opportunistic pathogen of diverse hosts, contains genes (referred to as the reb cluster) with potential to confer production of R-bodies and that have been implicated in virulence. Here, we show that products of the PA14 reb cluster associate with R-bodies and control stochastic expression of R-body structural genes. PA14 expresses reb genes during colonization of plant and nematode hosts, and R-body production is required for full virulence in nematodes. Analyses of nematode ribosome content and immune response indicate that P. aeruginosa R-bodies act via a mechanism involving ribosome cleavage and translational inhibition. Our observations provide insight into the biology of R-body production and its consequences during P. aeruginosa infection.
Topics: Animals; Bacterial Proteins; Biofilms; Caenorhabditis elegans; Phylogeny; Pseudomonas Infections; Pseudomonas aeruginosa; Virulence; Virulence Factors
PubMed: 34326342
DOI: 10.1038/s41467-021-24796-0 -
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 -
Journal of Global Antimicrobial... Mar 2020Pseudomonas aeruginosa is the most frequent infectious agent in cystic fibrosis patients. P. aeruginosa resistance to first line antibiotics limits therapeutic options,... (Comparative Study)
Comparative Study
OBJECTIVES
Pseudomonas aeruginosa is the most frequent infectious agent in cystic fibrosis patients. P. aeruginosa resistance to first line antibiotics limits therapeutic options, but the therapeutic potential of older generation antibiotics, such as fosfomycin is under investigation. Fosfomycin does not belong to any other antibiotic class and acts by inhibiting the biosynthesis of the bacterial cell wall during the initial phases. A major problem for the use of fosfomycin against P. aeruginosa is the absence of a clinical breakpoint, the last one of 32 μg/mL was proposed in 2013 by the CA-SFM (Comité de l'Antibiogramme de la Société Française de Microbiologie).
METHODS
Sixty-one strains of P. aeruginosa (thirty mucoid and thirty-one non mucoid) were collected from respiratory samples of cystic fibrosis patients. All isolates were identified by MALDI-TOF (Bruker, Bremen, Germany). Fosfomycin MICs against P. aeruginosa were measured using an automated system and confirmed by the gold standard method.
RESULTS
There was no significant difference between mucoid and non-mucoid strains. MIC distribution and susceptibility rates were obtained by agar dilution method and from this data we measured MIC50 and MIC90 which were equal to 32 μg/mL and 64 μg/mL, respectively. From automated method results we measured a very major error (VME), major error (ME) and categorical agreement (CA) which were equal to 0%, 11% and 89%, respectively. Comparing automated and agar dilution methods, a Cohen's kappa equal to 73% (0.726) was measured.
CONCLUSIONS
Our data suggest that fosfomycin has good effect against mucoid and non-mucoid strains of P. aeruginosa and automated systems can be implemented in clinical microbiology laboratories to assess fosfomycin with rapid and reproducible results.
Topics: Automation, Laboratory; Cystic Fibrosis; Fosfomycin; Humans; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 32105800
DOI: 10.1016/j.jgar.2020.02.014 -
Antimicrobial Resistance and Infection... Nov 2020The distribution of β-lactam resistance genes in P. aeruginosa is often closely related to the distribution of certain high-risk international clones. We used...
BACKGROUND
The distribution of β-lactam resistance genes in P. aeruginosa is often closely related to the distribution of certain high-risk international clones. We used whole-genome sequencing (WGS) to identify the predominant sequence types (ST) and β-lactamase genes in clinical isolates of multidrug-resistant (MDR)-P. aeruginosa from Qatar METHODS: Microbiological identification and susceptibility tests were performed by automated BD Phoenix™ system and manual Liofilchem MIC Test Strips.
RESULTS
Among 75 MDR-P. aeruginosa isolates; the largest proportions of susceptibility were to ceftazidime-avibactam (n = 36, 48%), followed by ceftolozane-tazobactam (30, 40%), ceftazidime (n = 21, 28%) and aztreonam (n = 16, 21.3%). All isolates possessed Class C and/or Class D β-lactamases (n = 72, 96% each), while metallo-β-lactamases were detected in 20 (26.7%) isolates. Eight (40%) metallo-β-lactamase producers were susceptible to aztreonam and did not produce any concomitant extended-spectrum β-lactamases. High risk ST235 (n = 16, 21.3%), ST357 (n = 8, 10.7%), ST389 and ST1284 (6, 8% each) were most frequent. Nearly all ST235 isolates (15/16; 93.8%) were resistant to all tested β-lactams.
CONCLUSION
MDR-P. aeruginosa isolates from Qatar are highly resistant to antipseudomonal β-lactams. High-risk STs are predominant in Qatar and their associated MDR phenotypes are a cause for considerable concern.
Topics: Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Whole Genome Sequencing; beta-Lactamases
PubMed: 33131487
DOI: 10.1186/s13756-020-00838-y -
Cell Reports Feb 2022The Pseudomonas quinolone signal (PQS) is a multifunctional quorum sensing molecule of key importance to P. aeruginosa. Here, we report that the lytic Pseudomonas...
The Pseudomonas quinolone signal (PQS) is a multifunctional quorum sensing molecule of key importance to P. aeruginosa. Here, we report that the lytic Pseudomonas bacterial virus LUZ19 targets this population density-dependent signaling system by expressing quorum sensing targeting protein (Qst) early during infection. We demonstrate that Qst interacts with PqsD, a key host quinolone signal biosynthesis pathway enzyme, resulting in decreased levels of PQS and its precursor 2-heptyl-4(1H)-quinolone. The lack of a functional PqsD enzyme impairs LUZ19 infection but is restored by external supplementation of 2-heptyl-4(1H)-quinolone, suggesting that LUZ19 exploits the PQS system for successful infection. We establish a broad functional interaction network of Qst, which includes enzymes of cofactor biosynthesis pathways (CoaC/ThiD) and a non-ribosomal peptide synthetase pathway (PA1217). Qst therefore represents an exquisite example of intricate reprogramming of the bacterium by a phage, which may be further exploited as tool to combat antibiotic resistant bacterial pathogens.
Topics: Acetyltransferases; Anti-Bacterial Agents; Bacterial Proteins; Bacteriophages; Carbon; Metabolic Networks and Pathways; Metabolome; Metabolomics; Models, Biological; Pseudomonas aeruginosa; Quinolones; Quorum Sensing; Secondary Metabolism; Viral Proteins
PubMed: 35172131
DOI: 10.1016/j.celrep.2022.110372 -
Scientific Reports Jan 2021While considered an extracellular pathogen, Pseudomonas aeruginosa has been reported to be engulfed by macrophages in cellular and animal models. However, the role of...
While considered an extracellular pathogen, Pseudomonas aeruginosa has been reported to be engulfed by macrophages in cellular and animal models. However, the role of macrophages in P. aeruginosa clearance in vivo remains poorly studied. The major outer membrane porin OprF has been recently shown to be involved in P. aeruginosa fate within cultured macrophages and analysis of an oprF mutant may thus provide insights to better understand the relevance of this intramacrophage stage during infection. In the present study, we investigated for the first time the virulence of a P. aeruginosa oprF mutant in a vertebrate model that harbors functional macrophages, the zebrafish (Danio rerio) embryo, which offers powerful tools to address macrophage-pathogen interactions. We established that P. aeruginosa oprF mutant is attenuated in zebrafish embryos in a macrophage-dependent manner. Visualization and quantification of P. aeruginosa bacteria phagocytosed by macrophages after injection into closed cavities suggested that the attenuated phenotype of oprF mutant is not linked to higher macrophage recruitment nor better phagocytosis than wild-type strain. Using cultured macrophages, we showed an intramacrophage survival defect of P. aeruginosa oprF mutant, which is correlated with elevated association of bacteria with acidic compartments. Notably, treatment of embryos with bafilomycin, an inhibitor of acidification, increased the sensibility of embryos towards both wild-type and oprF mutant, and partially suppressed the attenuation of oprF mutant. Taken together, this work supports zebrafish embryo as state-of-the-art model to address in vivo the relevance of P. aeruginosa intramacrophage stage. Our results highlight the contribution of macrophages in the clearance of P. aeruginosa during acute infection and suggest that OprF protects P. aeruginosa against macrophage clearance by avoiding bacterial elimination in acidified phagosomes.
Topics: Animals; Bacterial Proteins; Gene Expression Regulation, Bacterial; Macrophages; Pseudomonas aeruginosa; Zebrafish
PubMed: 33432030
DOI: 10.1038/s41598-020-79678-0 -
Current Biology : CB Feb 2015Mechanosensing of surfaces in bacteria is a process that often uses obstruction of flagellum rotation to trigger behaviors such as adhesion and surface-associated...
Mechanosensing of surfaces in bacteria is a process that often uses obstruction of flagellum rotation to trigger behaviors such as adhesion and surface-associated movement. In a recent publication, the PilY1 protein of Pseudomonas aeruginosa has been implicated as a novel mechanosensor that stimulates virulence in response to surface attachment.
Topics: Bacterial Adhesion; Pseudomonas aeruginosa
PubMed: 25649820
DOI: 10.1016/j.cub.2014.12.026