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Journal of Bacteriology Jan 2020Airway infections associated with cystic fibrosis (CF) are polymicrobial. We reported previously that clinical isolates of promote the growth of a variety of...
Airway infections associated with cystic fibrosis (CF) are polymicrobial. We reported previously that clinical isolates of promote the growth of a variety of streptococcal species. To explore the mechanistic basis of this interaction, we performed a genetic screen to identify mutants of SK36 whose growth was no longer enhanced by PAO1. Mutations in the zinc uptake systems of SK36 reduced growth of these strains by 1 to 3 logs compared to that of wild-type SK36 when grown in coculture with PAO1, and exogenous zinc (0.1 to 10 μM) rescued the coculture defect of zinc uptake mutants of SK36. Zinc uptake mutants of SK36 had no obvious growth defect in monoculture. Consistent with competition for zinc driving coculture dynamics, SK36 grown in coculture with showed increased expression of zinc uptake genes compared to that of grown alone. Strains of PAO1 defective in zinc transport also supported ∼2-fold more growth by compared to that in coculture with wild-type PAO1. An analysis of 118 CF sputum samples revealed that total zinc levels varied from ∼5 to 145 μM. At relatively low zinc levels, and spp. were found in approximately equal abundance; at higher zinc levels, we observed a decline in relative abundance of spp., perhaps as a result of increasing zinc toxicity. Together, our data indicate that the relative abundances of these microbes in the CF airway may be impacted by zinc levels. Polymicrobial infections in CF cases likely impact patient health, but the mechanism(s) underlying such interactions is poorly understood. Here, we show using an model system that interactions between and are modulated by zinc availability, and clinical data are consistent with this model. Together with previous studies, our work supports a role for metal homeostasis as a key factor driving microbial interactions.
Topics: Biofilms; Coculture Techniques; Microbial Interactions; Pseudomonas aeruginosa; Streptococcus sanguis; Zinc
PubMed: 31685535
DOI: 10.1128/JB.00618-19 -
Biomolecules Jul 2020is a facultative pathogen that can cause, inter alia, acute or chronic pneumonia in predisposed individuals. The gram-negative bacterium displays considerable genomic... (Comparative Study)
Comparative Study
is a facultative pathogen that can cause, inter alia, acute or chronic pneumonia in predisposed individuals. The gram-negative bacterium displays considerable genomic and phenotypic diversity that is also shaped by small molecule secondary metabolites. The discrimination of virulence phenotypes is highly relevant to the diagnosis and prognosis of infections. In order to discover small molecule metabolites that distinguish different virulence phenotypes of , 35 clinical strains were cultivated under standard conditions, characterized in terms of virulence and biofilm phenotype, and their metabolomes were investigated by untargeted liquid chromatography-mass spectrometry. The data was both mined for individual candidate markers as well as used to construct statistical models to infer the virulence phenotype from metabolomics data. We found that clinical strains that differed in their virulence and biofilm phenotype also had pronounced divergence in their metabolomes, as underlined by 332 features that were significantly differentially abundant with fold changes greater than 1.5 in both directions. Important virulence-associated secondary metabolites like rhamnolipids, alkyl quinolones or phenazines were found to be strongly upregulated in virulent strains. In contrast, we observed little change in primary metabolism. A hitherto novel cationic metabolite with a sum formula of CHN could be identified as a candidate biomarker. A random forest model was able to classify strains according to their virulence and biofilm phenotype with an area under the Receiver Operation Characteristics curve of 0.84. These findings demonstrate that untargeted metabolomics is a valuable tool to characterize virulence, and to explore interrelations between clinically important phenotypic traits and the bacterial metabolome.
Topics: Biofilms; Chromatography, Liquid; Humans; Metabolomics; Models, Theoretical; Phenotype; Principal Component Analysis; Prognosis; Pseudomonas Infections; Pseudomonas aeruginosa; Secondary Metabolism; Tandem Mass Spectrometry; Virulence
PubMed: 32668735
DOI: 10.3390/biom10071041 -
MBio Jun 2015Phenotypic variability among bacteria depends on gene expression in response to different environments, and it also reflects differences in genomic structure. In this...
UNLABELLED
Phenotypic variability among bacteria depends on gene expression in response to different environments, and it also reflects differences in genomic structure. In this study, we analyzed transcriptome sequencing (RNA-seq) profiles of 151 Pseudomonas aeruginosa clinical isolates under standard laboratory conditions and of one P. aeruginosa type strain under 14 different environmental conditions. Our approach allowed dissection of the impact of the genetic background versus environmental cues on P. aeruginosa gene expression profiles and revealed that phenotypic variation was larger in response to changing environments than between genomically different isolates. We demonstrate that mutations within the global regulator LasR affect more than one trait (pleiotropy) and that the interaction between mutations (epistasis) shapes the P. aeruginosa phenotypic plasticity landscape. Because of pleiotropic and epistatic effects, average genotype and phenotype measures appeared to be uncorrelated in P. aeruginosa.
IMPORTANCE
This work links experimental data of unprecedented complexity with evolution theory and delineates the transcriptional landscape of the opportunistic pathogen Pseudomonas aeruginosa. We found that gene expression profiles are most strongly influenced by environmental cues, while at the same time the transcriptional profiles were also shaped considerably by genetic variation within global regulators. The comprehensive set of transcriptomic and genomic data of more than 150 clinical P. aeruginosa isolates will be made publically accessible to all researchers via a dedicated web interface. Both Pseudomonas specialists interested in expression and regulation of specific genes and researchers from other fields with more global interest in the phenotypic and genotypic variation of this important model species can access all information on various levels of detail.
Topics: Adaptation, Physiological; Epistasis, Genetic; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Gene Regulatory Networks; Genetic Variation; Genotype; Molecular Sequence Data; Phenotype; Pseudomonas aeruginosa; Sequence Analysis, DNA
PubMed: 26126853
DOI: 10.1128/mBio.00749-15 -
The European Respiratory Journal Apr 2017To characterise populations during chronic lung infections of non-cystic fibrosis bronchiectasis patients, we used whole-genome sequencing to 1) assess the diversity...
To characterise populations during chronic lung infections of non-cystic fibrosis bronchiectasis patients, we used whole-genome sequencing to 1) assess the diversity of and the prevalence of multilineage infections; 2) seek evidence for cross-infection or common source acquisition; and 3) characterise adaptations.189 isolates, obtained from the sputa of 91 patients attending 16 adult bronchiectasis centres in the UK, were whole-genome sequenced.Bronchiectasis isolates were representative of the wider population. Of 24 patients from whom multiple isolates were examined, there were seven examples of multilineage infections, probably arising from multiple infection events. The number of nucleotide variants between genomes of isolates from different patients was in some cases similar to the variations observed between isolates from individual patients, implying the possible occurrence of cross-infection or common source acquisition.Our data indicate that during infections of bronchiectasis patients, populations adapt by accumulating loss-of-function mutations, leading to changes in phenotypes including different modes of iron acquisition and variations in biofilm-associated polysaccharides. The within-population diversification suggests that larger scale longitudinal surveillance studies will be required to capture cross-infection or common source acquisition events at an early stage.
Topics: Biofilms; Bronchiectasis; Cross Infection; Cystic Fibrosis; Humans; Phenotype; Pseudomonas Infections; Pseudomonas aeruginosa; Sputum; United Kingdom; Virulence Factors; Whole Genome Sequencing
PubMed: 28446558
DOI: 10.1183/13993003.02108-2016 -
Applied and Environmental Microbiology May 2020A longstanding awareness in generating resistance to common antimicrobial therapies by Gram-negative bacteria has made them a major threat to global health. The...
A longstanding awareness in generating resistance to common antimicrobial therapies by Gram-negative bacteria has made them a major threat to global health. The application of antimicrobial peptides as a therapeutic agent would be a great opportunity to combat bacterial diseases. Here, we introduce a new antimicrobial peptide (∼8.3 kDa) from probiotic strain ATCC 4356, designated acidocin 4356 (ACD). This multifunctional peptide exerts its anti-infective ability against through an inhibitory action on virulence factors, bacterial killing, and biofilm degradation. Reliable performance over tough physiological conditions and low hemolytic activity confirmed a new hope for the therapeutic setting. Antibacterial kinetic studies using flow cytometry technique showed that the ACD activity is related to the change in permeability of the membrane. The results obtained from molecular dynamic (MD) simulation were perfectly suited to the experimental data of ACD behavior. The structure-function relationship of this natural compound, along with the results of transmission electron microscopy analysis and MD simulation, confirmed the ability of the ACD aimed at enhancing bacterial membrane perturbation. The peptide was effective in the treatment of infection in mouse model. The results support the therapeutic potential of ACD for the treatment of infections. Multidrug-resistant bacteria are a major threat to global health, and the bacterium with the ability to form biofilms is considered one of the main causative agents of nosocomial infections. Traditional antibiotics have failed because of increased resistance. Thus, finding new biocompatible antibacterial drugs is essential. Antimicrobial peptides are produced by various organisms as a natural defense mechanism against pathogens, inspiring the possible design of the next generation of antibiotics. In this study, a new antimicrobial peptide was isolated from ATCC 4356, counteracting both biofilm and planktonic cells of A detailed investigation was then conducted concerning the functional mechanism of this peptide by using fluorescence techniques, electron microscopy, and methods. The antibacterial and antibiofilm properties of this peptide may be important in the treatment of infections.
Topics: Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Bacterial Proteins; Cell Membrane; Kinetics; Lactobacillus acidophilus; Molecular Dynamics Simulation; Pseudomonas Infections; Pseudomonas aeruginosa; Virulence
PubMed: 32169940
DOI: 10.1128/AEM.00367-20 -
Nucleic Acids Research Feb 2021Bacteria deploy multiple defenses to prevent mobile genetic element (MGEs) invasion. CRISPR-Cas immune systems use RNA-guided nucleases to target MGEs, which counter...
Bacteria deploy multiple defenses to prevent mobile genetic element (MGEs) invasion. CRISPR-Cas immune systems use RNA-guided nucleases to target MGEs, which counter with anti-CRISPR (Acr) proteins. Our understanding of the biology and co-evolutionary dynamics of the common Type I-C CRISPR-Cas subtype has lagged because it lacks an in vivo phage-host model system. Here, we show the anti-phage function of a Pseudomonas aeruginosa Type I-C CRISPR-Cas system encoded on a conjugative pKLC102 island, and its Acr-mediated inhibition by distinct MGEs. Seven genes with anti-Type I-C function (acrIC genes) were identified, many with highly acidic amino acid content, including previously described DNA mimic AcrIF2. Four of the acr genes were broad spectrum, also inhibiting I-E or I-F P. aeruginosa CRISPR-Cas subtypes. Dual inhibition comes at a cost, however, as simultaneous expression of Type I-C and I-F systems renders phages expressing the dual inhibitor AcrIF2 more sensitive to targeting. Mutagenesis of numerous acidic residues in AcrIF2 did not impair anti-I-C or anti-I-F function per se but did exacerbate inhibition defects during competition, suggesting that excess negative charge may buffer DNA mimics against competition. Like AcrIF2, five of the Acr proteins block Cascade from binding DNA, while two function downstream, likely preventing Cas3 recruitment or activity. One such inhibitor, AcrIC3, is found in an 'anti-Cas3' cluster within conjugative elements, encoded alongside bona fide Cas3 inhibitors AcrIF3 and AcrIE1. Our findings demonstrate an active battle between an MGE-encoded CRISPR-Cas system and its diverse MGE targets.
Topics: Bacteriophages; CRISPR-Associated Proteins; CRISPR-Cas Systems; DNA Cleavage; Interspersed Repetitive Sequences; Pseudomonas aeruginosa; Viral Proteins
PubMed: 33544853
DOI: 10.1093/nar/gkab006 -
Scientific Reports Jan 2021Pseudomonas aeruginosa is a globally-distributed bacterium often found in medical infections. The opportunistic pathogen uses a different, carbon catabolite repression...
Pseudomonas aeruginosa is a globally-distributed bacterium often found in medical infections. The opportunistic pathogen uses a different, carbon catabolite repression (CCR) strategy than many, model microorganisms. It does not utilize a classic diauxie phenotype, nor does it follow common systems biology assumptions including preferential consumption of glucose with an 'overflow' metabolism. Despite these contradictions, P. aeruginosa is competitive in many, disparate environments underscoring knowledge gaps in microbial ecology and systems biology. Physiological, omics, and in silico analyses were used to quantify the P. aeruginosa CCR strategy known as 'reverse diauxie'. An ecological basis of reverse diauxie was identified using a genome-scale, metabolic model interrogated with in vitro omics data. Reverse diauxie preference for lower energy, nonfermentable carbon sources, such as acetate or succinate over glucose, was predicted using a multidimensional strategy which minimized resource investment into central metabolism while completely oxidizing substrates. Application of a common, in silico optimization criterion, which maximizes growth rate, did not predict the reverse diauxie phenotypes. This study quantifies P. aeruginosa metabolic strategies foundational to its wide distribution and virulence including its potentially, mutualistic interactions with microorganisms found commonly in the environment and in medical infections.
Topics: Bacterial Proteins; Humans; Models, Biological; Pseudomonas aeruginosa
PubMed: 33446818
DOI: 10.1038/s41598-020-80522-8 -
Medical Science Monitor : International... Apr 2016Pseudomonas aeruginosa infection remains a life-threatening complication after solid organ transplantation (SOT). We aimed to investigate the distribution and drug...
BACKGROUND
Pseudomonas aeruginosa infection remains a life-threatening complication after solid organ transplantation (SOT). We aimed to investigate the distribution and drug susceptibility of pathogens, and clinical characteristics of SOT recipients with Pseudomonas aeruginosa infections.
MATERIAL/METHODS
A total of 55 SOT recipients who developed 61 episodes of Pseudomonas aeruginosa infections between January 1, 2003 and July 31, 2015 were retrospectively analyzed. The distribution and the drug susceptibility of Pseudomonas aeruginosa were reviewed.
RESULTS
The most common site from which 61 Pseudomonas aeruginosa rods were isolated were the lungs (57.4%, n=37), followed by the blood (27.9%, n=17). There were 35, 18, and 9 recipients accompanied with a serum creatinine level of >1.5 mg/dL, lymphocyte count of <300/mm(3), and a serum albumin level of <30 g/L, respectively. Seven patients each presented with white blood cell count of >15,000/mm(3) and platelet count of <50,000/mm(3). There were 6 (10.9%) cases of septic shocks and 18 (32.7%) deaths. Antibiotic resistance rate of all Pseudomonas aeruginosa to 4 of 10 antibiotics investigated was more than 50%. Of these 61 Pseudomonas aeruginosa isolates, 47.5% were carbapenem-resistant. The rods were relatively sensitive to piperacillin-tazobactam, levofloxacin, amikacin, and cefoperazone-sulbactam (resistance rate <40%).
CONCLUSIONS
The clinical presentation of Pseudomonas aeruginosa infections included high body temperature, decreased platelet count, elevated white blood cell count, a high nosocomial origin and mortality, and onset in the late period after transplantation. According to our findings, piperacillin-tazobactam, levofloxacin, amikacin, and cefoperazone-sulbactam, alone or combination, are recommended to treat SOT recipients with Pseudomonas aeruginosa infections.
Topics: Adult; Anti-Bacterial Agents; Demography; Drug Resistance, Microbial; Female; Humans; Male; Pseudomonas Infections; Pseudomonas aeruginosa; Transplant Recipients; Transplantation
PubMed: 27045418
DOI: 10.12659/msm.896026 -
Emerging Infectious Diseases Jun 2018We recovered VIM-2 carbapenemase-producing Pseudomonas aeruginosa isolates from an infected dog, its owner, and the domestic environment. Genomic investigation revealed...
We recovered VIM-2 carbapenemase-producing Pseudomonas aeruginosa isolates from an infected dog, its owner, and the domestic environment. Genomic investigation revealed household transmission of the high-risk hospital clone sequence type 233 in the human-animal-environment interface. Results suggest zooanthroponotic transmission of VIM-2-producing P. aeruginosa in the household following the patient's hospital discharge.
Topics: Animals; Anti-Bacterial Agents; Brazil; Dog Diseases; Dogs; Drug Resistance, Bacterial; Humans; Microbial Sensitivity Tests; Pseudomonas Infections; Pseudomonas aeruginosa; Zoonoses; beta-Lactamases
PubMed: 29774849
DOI: 10.3201/eid2406.180335 -
Cytometry. Part a : the Journal of the... May 2019Pseudomonas aeruginosa is a Gram-negative bacterium that is abundant in the environment and water systems, with strains that cause serious infections, especially in...
Pseudomonas aeruginosa is a Gram-negative bacterium that is abundant in the environment and water systems, with strains that cause serious infections, especially in patients with compromised immune systems. In times of stress or as part of its natural life cycle, P. aeruginosa can adopt a viable but not culturable (VBNC) state, which renders it undetectable by current conventional food and water testing methods and makes it highly resistant to antibiotic treatment. Specific conditions can resuscitate these coccoid VBNC P. aeruginosa cells, which returns them to their active, virulent rod-shaped form. Underreporting the VBNC cells of P. aeruginosa by standard culture-based methods in water distribution systems may therefore pose serious risks to public health. As such, being able to accurately detect and quantify the presence of VBNC P. aeruginosa, especially in a hospital setting, is of critical importance. Herein, we describe a method to analyze VBNC P. aeruginosa using imaging flow cytometry. With this technique, we can accurately distinguish between active and VBNC forms. We also show here that association of VBNC P. aeruginosa with Acanthamoeba polyphaga results in resuscitation of P. aeruginosa to an active form within 2 h. Our approach could provide an alternative, reliable detection method of VBNC P. aeruginosa when coupled with species-specific staining. Most importantly, our experiments demonstrate that the coculture with amoebae can lead to a resuscitation of P. aeruginosa of culturable morphology after only 2 h, indicating that VBNC P. aeruginosa could potentially resuscitate in piped water (healthcare) environments colonized with amoebae. © 2019 International Society for Advancement of Cytometry.
Topics: Acanthamoeba; Green Fluorescent Proteins; Image Cytometry; Microbial Viability; Phagocytosis; Pseudomonas aeruginosa; Trophozoites
PubMed: 30985067
DOI: 10.1002/cyto.a.23768