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The Journal of Antimicrobial... Jul 2024Carbapenem-resistant Pseudomonas aeruginosa are being increasingly described worldwide. Here, we investigated the molecular mechanisms underlying carbapenem resistance...
BACKGROUND
Carbapenem-resistant Pseudomonas aeruginosa are being increasingly described worldwide. Here, we investigated the molecular mechanisms underlying carbapenem resistance in an extremely drug-resistant P. aeruginosa isolate from a neonatal intensive care unit in Morocco.
MATERIALS AND METHODS
P. aeruginosa strain O82J1 was identified using MALDI-TOF-MS. Carba NP, immunochromatographic assay NG Carba5 and antimicrobial susceptibility testing using disc diffusion and microbroth were performed. Whole-genome sequencing using the Illumina and MinION technologies and different software packages available at the Center of Genomic Epidemiology were used to predict the resistome, sequence type and plasmid types.
RESULTS
P. aeruginosa O82J1 co-expressed two metallo-β-lactamases, blaNDM-1 and blaVIM-2, and was susceptible to colistin and apramycin only. It belonged to ST773 that is frequently reported worldwide as a high-risk P. aeruginosa clone. The blaVIM-2 gene was integron-borne on a IncP-2 465-kb plasmid, whereas the blaNDM-1 gene was chromosomally encoded and embedded in an integrative conjugative element, probably at the origin of its acquisition. A total of 23 antimicrobial resistance genes were detected including a blaPER-1 ESBL gene, and an 16S-rRNA methyltransferase gene rmtB.
CONCLUSIONS
The isolation of XDR P. aeruginosa isolates expressing several carbapenemases in a neonatal intensive care unit is of great concern due to the reduced treatment options, relying only on colistin, but not recommended in neonates, and apramycin, not yet approved for human therapy. Concerns were further elevated due to the resistance to cefiderocol and ATM/AVI, two novel and last-resort antibiotics recommended to treat infections caused by Gram-negative bacteria, particularly XDR P. aeruginosa in adults.
Topics: beta-Lactamases; Pseudomonas aeruginosa; Humans; Infant, Newborn; Morocco; Pseudomonas Infections; Anti-Bacterial Agents; Neonatal Sepsis; Microbial Sensitivity Tests; Plasmids; Whole Genome Sequencing; Intensive Care Units, Neonatal; Drug Resistance, Multiple, Bacterial; Carbapenems
PubMed: 38804143
DOI: 10.1093/jac/dkae153 -
Environmental Microbiology Sep 2023Pseudomonads are considered to be among the most widespread culturable bacteria in mesophilic environments. The evolutive success of Pseudomonas species can be... (Review)
Review
Pseudomonads are considered to be among the most widespread culturable bacteria in mesophilic environments. The evolutive success of Pseudomonas species can be attributed to their metabolic versatility, in combination with a set of additional functions that enhance their ability to colonize different niches. These include the production of secondary metabolites involved in iron acquisition or having a detrimental effect on potential competitors, different types of motility, and the capacity to establish and persist within biofilms. Although biofilm formation has been extensively studied using the opportunistic pathogen Pseudomonas aeruginosa as a model organism, a significant body of knowledge is also becoming available for non-pathogenic Pseudomonas. In this review, we focus on the mechanisms that allow Pseudomonas putida to colonize biotic and abiotic surfaces and adapt to sessile life, as a relevant persistence strategy in the environment. This species is of particular interest because it includes plant-beneficial strains, in which colonization of plant surfaces may be relevant, and strains used for environmental and biotechnological applications, where the design and functionality of biofilm-based bioreactors, for example, also have to take into account the efficiency of bacterial colonization of solid surfaces. This work reviews the current knowledge of mechanistic and regulatory aspects of biofilm formation by P. putida and pinpoints the prospects in this field.
Topics: Pseudomonas putida; Pseudomonas; Biofilms; Pseudomonas aeruginosa; Plants
PubMed: 37045787
DOI: 10.1111/1462-2920.16385 -
BMC Microbiology Jul 2020Pseudomonas aeruginosa is the most common Gram-negative pathogen responsible for chronic wound infections, such as diabetic foot infections, and further exacerbates the...
BACKGROUND
Pseudomonas aeruginosa is the most common Gram-negative pathogen responsible for chronic wound infections, such as diabetic foot infections, and further exacerbates the treatment options and cost of such conditions. Hypertonic glucose, a commonly used prolotherapy solution, can accelerate the proliferation of granulation tissue and improve microcirculation in wounds. However, the action of hypertonic glucose on bacterial pathogens that infect wounds is unclear. In this study, we investigated the inhibitory effects of hypertonic glucose on multidrug-resistant P. aeruginosa strains isolated from diabetic foot infections. Hypertonic glucose represents a novel approach to control chronic wound infections caused by P. aeruginosa.
RESULTS
Four multidrug-resistant P. aeruginosa clinical strains isolated from diabetic foot ulcers from a tertiary hospital in China and the reference P. aeruginosa PAO1 strain were studied. Hypertonic glucose significantly inhibited the growth, biofilm formation, and swimming motility of P. aeruginosa clinical strains and PAO1. Furthermore, hypertonic glucose significantly reduced the production of pyocyanin and elastase virulence factors in P. aeruginosa. The expression of major quorum sensing genes (lasI, lasR, rhlI, and rhlR) in P. aeruginosa were all downregulated in response to hypertonic glucose treatment. In a Galleria mellonella larvae infection model, the administration of hypertonic glucose was shown to increase the survival rates of larvae infected by P. aeruginosa strains (3/5).
CONCLUSIONS
Hypertonic glucose inhibited the growth, biofilm formation, and swimming motility of P. aeruginosa, as well as reduced the production of virulence factors and quorum sensing gene expression. Further studies that investigate hypertonic glucose therapy should be considered in treating chronic wound infections.
Topics: Bacterial Proteins; Biofilms; China; Diabetic Foot; Drug Resistance, Multiple, Bacterial; Gene Expression Regulation, Bacterial; Glucose Solution, Hypertonic; Humans; Microbial Sensitivity Tests; Microbial Viability; Pancreatic Elastase; Pseudomonas aeruginosa; Pyocyanine; Quorum Sensing; Tertiary Care Centers; Virulence Factors
PubMed: 32646366
DOI: 10.1186/s12866-020-01889-2 -
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 -
MBio Mar 2020The global stress response controlled by the alternative sigma factor RpoS protects enteric bacteria from a variety of environmental stressors. The role of RpoS in...
The global stress response controlled by the alternative sigma factor RpoS protects enteric bacteria from a variety of environmental stressors. The role of RpoS in other, nonenteric bacteria, such as the opportunistic pathogen , is less well understood. Here, we employed experimental social evolution to reveal that cooperative behavior via secreted public goods is an important function in the RpoS response of Using whole-genome sequencing, we identified loss-of-function mutants among isolates evolved in a protein growth medium that requires extracellular proteolysis. We found that mutants comprise up to 25% of the evolved population and that they behave as social cheaters, with low fitness in isolation but high fitness in mixed culture with the cooperating wild type. We conclude that mutants cheat because they exploit an RpoS-controlled public good produced by the wild type, the secreted aminopeptidase PaAP, and because they do not carry the metabolic costs of expressing PaAP and many other gene products in the large RpoS regulon. Our results suggest that PaAP is an integral part of a proteolytic sequence in that permits the utilization of protein as a nutrient source. Our work broadens the scope of stress response functions in bacteria. Bacterial stress responses are generally considered protective measures taken by individual cells. Enabled by an experimental evolution approach, we describe a contrasting property, collective nutrient acquisition, in the RpoS-dependent stress response of the opportunistic human pathogen Specifically, we identify the secreted aminopeptidase (PaAP) as an essential RpoS-controlled function in extracellular proteolysis. As a secreted "public good," PaAP permits cheating by mutants that save the metabolic costs of expressing RpoS-controlled genes dispensable under the given growth conditions. Proteolytic enzymes are important virulence factors in pathogenesis and constitute a potential target for antimicrobial therapy. More broadly, our work contributes to recent findings in higher organisms that stress affects not only individual fitness and competitiveness but also cooperative behavior.
Topics: Aminopeptidases; Bacterial Proteins; Mutation; Proteolysis; Pseudomonas aeruginosa; Sigma Factor; Stress, Physiological; Whole Genome Sequencing
PubMed: 32184248
DOI: 10.1128/mBio.03090-19 -
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 Drug Resistance (Larchmont,... Jul 2021As a potential "Superbug," remains the leading concern in antimicrobial resistance. In this study, the emergence of clinical isolate was found to carry and on the...
As a potential "Superbug," remains the leading concern in antimicrobial resistance. In this study, the emergence of clinical isolate was found to carry and on the chromosome and on a plasmid. A clinical strain Guangzhou-PaeC79 with an extensively drug-resistant phenotype was isolated, which was resistant to all classes of clinical commonly used antibiotics. It contains one chromosomal DNA and one plasmid, with seven acquired antimicrobial resistance genes identified on the chromosome, including carbapenem resistance gene and fluoroquinolone resistance gene , and carbapenem resistance gene located on an IncP-6-type plasmid pPAEC79 carrying a Tn-like element. Carriage of any two of the resistance genes has never been previously reported, and simultaneous carriage of three and may explain the bacterial phenotype as high-level resistance to imipenem and meropenem (≥16 μg/mL) and resistance to ciprofloxacin and levofloxacin.
Topics: Adult; Anti-Bacterial Agents; China; Drug Resistance, Multiple, Bacterial; Genes, Bacterial; Humans; Male; Microbial Sensitivity Tests; Plasmids; Pseudomonas Infections; Pseudomonas aeruginosa
PubMed: 33570473
DOI: 10.1089/mdr.2020.0420 -
Current Microbiology Mar 2020Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes serious infections in humans, notably cystic fibrosis. P. aeruginosa faces various stresses...
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes serious infections in humans, notably cystic fibrosis. P. aeruginosa faces various stresses such as oxidative stress either in the environment or within the host during infection. In the present study, the influence of oxidative stress on both Pseudomonas antibiotic susceptibility and host pathogenesis was characterized. Prior exposure to HO significantly altered P. aeruginosa susceptibility to tested antibiotics; colistin, ciprofloxacin, tobramycin, and ceftazidime. The minimum inhibitory concentrations (MICs) of tested antibiotics either increased or decreased following HO exposure. Importantly, RT-qPCR revealed that expression of quorum sensing genes, that regulate virulence factors production in P. aeruginosa, was significantly higher in unstressed relative to HO-stressed cells. The impact of P. aeruginosa exposure to oxidative stress by HO on bacterial pathogenesis was investigated using in vivo mice infection model. Interestingly, exposure to oxidative stress markedly reduces P. aeruginosa pathogenesis in mice. Unstressed P. aeruginosa was able to kill more mice as compared to HO-stressed bacteria. In addition, body weight of mice infected with unstressed P. aeruginosa was lower than that of mice inoculated with stressed bacteria. Isolated organs (spleen, liver, and kidney) from mice infected with unstressed bacteria exhibited increased weight as well as bacterial load in comparison with mice infected with stressed bacteria. In summary, current data highlight the impact of oxidative stress on P. aeruginosa antibiotic susceptibility as well as host pathogenesis. These findings could be helpful in treatment of infections caused by this important pathogen.
Topics: Animals; Anti-Bacterial Agents; Bacterial Load; Disease Susceptibility; Hydrogen Peroxide; Mice; Microbial Sensitivity Tests; Oxidative Stress; Pseudomonas Infections; Pseudomonas aeruginosa; Quorum Sensing; Virulence Factors
PubMed: 31907601
DOI: 10.1007/s00284-019-01858-7 -
Journal of Bacteriology Sep 2019The ability of to form biofilms, which are communities of cells encased in a self-produced extracellular matrix, protects the cells from antibiotics and the host immune... (Review)
Review
The ability of to form biofilms, which are communities of cells encased in a self-produced extracellular matrix, protects the cells from antibiotics and the host immune response. While some biofilm matrix components, such as exopolysaccharides and extracellular DNA, are relatively well characterized, the extracellular matrix proteins remain understudied. Multiple proteomic analyses of the soluble biofilm matrix and outer membrane vesicles, which are a component of the matrix, have identified OprF as an abundant matrix protein. To date, the few reports on the effects of mutations on biofilm formation are conflicting, and little is known about the potential role of OprF in the biofilm matrix. The majority of OprF studies focus on the protein as a cell-associated porin. As a component of the outer membrane, OprF assumes dual conformations and is involved in solute transport, as well as cell envelope integrity. Here, we review the current literature on OprF in , discussing how the structure and function of the cell-associated and matrix-associated protein may affect biofilm formation and pathogenesis in order to inform future research on this understudied matrix protein.
Topics: Animals; Bacterial Proteins; Biofilms; Extracellular Matrix; Humans; Proteomics; Pseudomonas aeruginosa; Virulence
PubMed: 31010902
DOI: 10.1128/JB.00050-19 -
Emerging Microbes & Infections 2020Here, we presented 11 cases with colistin-resistant infection and co-existence of OXA-48 and NDM-1 in the ST235 high-risk clone. The molecular analyses were performed...
Here, we presented 11 cases with colistin-resistant infection and co-existence of OXA-48 and NDM-1 in the ST235 high-risk clone. The molecular analyses were performed by Sanger sequencing and RT-PCR. The eight patients (72.7%) had an invasive infection and three (27.3%) had colonization. The 30-day mortality rate was 87.5% (7/8). Three patients (37.5%, 3/8) received colistin therapy before isolation of . In the Multilocus sequence typing (MLST) analysis of 11 isolates, eight (72.7%) isolates belonged to ST235 clone. All isolates were NDM-1 positive, and nine isolates (81.8%) were found to be positive for both OXA-48 and NDM-1. Sequences of and revealed numerous insertions and deletions in all isolates. In 10 isolates and were found to be upregulated. In conclusion, the co-existence of OXA-48 and NDM-1 genes in colistin-resistant ST235 high-risk clone indicates the spread of carbapenemases in clinical isolates and highlights need of continuous surveillance for high-risk clones of .
Topics: Anti-Bacterial Agents; Bacterial Proteins; Colistin; Drug Resistance, Bacterial; Humans; Microbial Sensitivity Tests; Pseudomonas Infections; Pseudomonas aeruginosa; beta-Lactamases
PubMed: 31964275
DOI: 10.1080/22221751.2020.1713025