Project description:Staphylococcus aureus and Pseudomonas aeruginosa are the most prevalent pathogens that colonize structurally abnormal airways such as those in Cystic Fibrosis (CF) and other chronic obstructive lung diseases. Although these bacteria seem to succeed one another, CF patients acquire coinciding P. aeruginosa and S. aureus pulmonary infections, being co-infection usually associated with decreased lung function and increased frequency of pulmonary exacerbations. In addition, P. aeruginosa and S. aureus pathogens adopt a biofilm mode of growth, which contributes to high tolerance to antibiotic treatment and the recalcitrant nature of these chronic coinfections, leading to significant patient morbidity and mortality. Interactions between P. aeruginosa and S. aureus have been widely studied and it is commonly admitted that P. aeruginosa outcompetes S. aureus, perhaps outcompeting S. aureus for limited nutrients or producing anti-staphylococcal compounds, having S. aureus a minimal contribution to the overall course of the infection. However, the molecular mechanisms behind these interactions are largely unknown. Herein, we decided to characterize the full transcriptome of these dual-species biofilms, to unveil important molecular interactions that can occur between these two bacterial species that are relevant for the pathogenesis of the entire consortia. Our data provide novel insights into the role of interspecies interactions in the pathogenesis of P. aeruginosa and S. aureus co-infections and will contribute to future studies by the research community.
Project description:Pseudomonas aeruginosa and Staphylococcus aureus are often co-isolated in persistent infections. The goal of this study was to determine how secreted products from S. aureus affect gene expression in P. aeruginosa. Therefore, media control or S. aureus supernatant was added to P. aeruginosa cultures at 25% total volume and gene expression was measured at 20 min, 1 h, and 2 h using RNA-seq. Overall, after addition of S. aureus supernatant, there was an upregulation in genes involved in metal deprivation and intermediate metabolite uptake.
Project description:Pseudomonas aeruginosa and Staphylococcus aureus are often co-isolated in persistent infections. The goal of this study was to determine how secreted products that were identified in S. aureus supernatant affect gene expression in P. aeruginosa. Therefore, media control, the indicated products in media, or S. aureus supernatant was added to P. aeruginosa cultures at 25% total volume and gene expression was measured at 20 min and 2 h using RNA-seq. The individual products induced distinct pathways in P. aeruginosa. The products in combination recapitulated much of the differential gene expression seen in P. aeruginosa in response to S. aureus supernatant.
Project description:To provide a more detailed survey of adaptive changes in the physiology of P. aeruginosa (PA) during long-term infection of the cystic fibrosis (CF) lung, we performed a comparative proteome and transcriptome analysis of a set of isogenic sequential non-mutator and mutator isolates from three selected CF patients. Recently, we showed that during CF lung persistence PA mutators converge to a virulence-attenuated phenotype. In this study, we demonstrate that besides virulence-associated traits (VATs) the adaptation process of PA predominantly comprises metabolic pathways. In end-stage mutator strains, transcripts of genes encoding VATs, chemotaxis, degradation of aromatic compounds and several two-component regulatory systems were decreased. In contrast, several transcripts of genes or proteins involved in metabolism of fatty acids, nucleotides, amino acids and the generation of energy were increased. Of particular interest is the increased expression level of genes involved in (i) the anaerobic arginine-deiminase pathway, (ii) the anaerobic respiration such as nitrate-uptake protein OprF, redox-active azurin and cytchrome c551 peroxidase, (iii) the micro-aerobic respiration such as high oxygen-affinity cytochrome oxidase cbb3 (iv) the tricarboxylic acid cycle (TCA), glyoxylate shunt and anaplerotic carboxylation reactions to oxaloacetate. Strikingly, an increased transcription of the anaerobic regulator gene anr correlates with the up-regulation of ANR-dependent genes. In conclusion, these changes in transcriptome and proteome indicate an adaptive shift towards constitutive expression of genes of metabolic pathways obviously required for growth under micro-aerobic and nutritional conditions of suppurative CF lung tissue. Finally, these results provide us with new targets for antimicrobial agents and biomarkers reflecting adaptation of PA towards progressive CF lung disease. Experiment Overall Design: P. aeruginosa isolates recovered from different time points of chronic cystic fibrosis lung disease were cultered in vitro, harvested for RNA extraction and hybridization on Affymetrix microarrays. We compared the transcriptome (triplicate microarrays) of early non-mutator P. aeruginosa isolates with late mutator isolates with high mutation frequency probably the driving force of an efficient adaptation to changing environements to conclude from differences in gene expression to the requirements of CF lung environment. Experiment Overall Design: Second publication of array data to be added later
Project description:<p>While bacterial metabolism is known to impact antibiotic efficacy and virulence, the metabolic capacities of individual microbes in cystic fibrosis lung infections are difficult to disentangle from sputum samples. Here, we show that untargeted metabolomic profiling of supernatants of multiple strains of<em> Pseudomonas aeruginosa</em> and <em>Staphylococcus aureus </em>grown in monoculture in synthetic cystic fibrosis media (SCFM) reveal distinct species-specific metabolic signatures with limited strain-to-strain variability. The majority of metabolites significantly consumed by <em>S. aureus </em>were also consumed by <em>P. aeruginosa</em>, indicating that <em>P. aeruginosa</em> has the flexibility to metabolically outcompete<em> S. aureus </em>in coculture even in the absence of other pathogen-pathogen interactions. Finally, metabolites that were uniquely produced by one species or the other were identified. Specifically, the virulence factor precursor anthranilic acid as well as the quinoline 2,4-Quinolinediol (DHQ) were robustly produced across all tested strains of <em>P. aeruginosa</em>. Through the direct comparison of the extracellular metabolism of <em>P. aeruginosa</em> and <em>S. aureus</em> in a physiologically relevant environment, this work provides insight towards the potential metabolic interactions in vivo and supports the development of species-specific diagnostic markers of infection.</p>
Project description:Pseudomonas aeruginosa and Staphylococcus aureus are often co-isolated in persistent infections. The goal of this study was to determine how secreted products from S. aureus affect gene expression in surface-associated P. aerguinosa undergoing emergent motility. Therefore, media salts control or S. aureus supernatant was added to agar plates at 25% total volume. P. aeruginosa was inoculated on the agar and gene expression was measured from the leading edge after 17 h incubation using RNA-seq. P. aeruginosa moving on the agar containing S. aureus supernatant had an upregulation in genes involved in intermediate metabolite uptake and a downregulation in heme biosynthesis, response to heat, Type III Secretion System, and aerobic respiration pathways.
Project description:To provide a more detailed survey of adaptive changes in the physiology of P. aeruginosa (PA) during long-term infection of the cystic fibrosis (CF) lung, we performed a comparative proteome and transcriptome analysis of a set of isogenic sequential non-mutator and mutator isolates from three selected CF patients. Recently, we showed that during CF lung persistence PA mutators converge to a virulence-attenuated phenotype. In this study, we demonstrate that besides virulence-associated traits (VATs) the adaptation process of PA predominantly comprises metabolic pathways. In end-stage mutator strains, transcripts of genes encoding VATs, chemotaxis, degradation of aromatic compounds and several two-component regulatory systems were decreased. In contrast, several transcripts of genes or proteins involved in metabolism of fatty acids, nucleotides, amino acids and the generation of energy were increased. Of particular interest is the increased expression level of genes involved in (i) the anaerobic arginine-deiminase pathway, (ii) the anaerobic respiration such as nitrate-uptake protein OprF, redox-active azurin and cytchrome c551 peroxidase, (iii) the micro-aerobic respiration such as high oxygen-affinity cytochrome oxidase cbb3 (iv) the tricarboxylic acid cycle (TCA), glyoxylate shunt and anaplerotic carboxylation reactions to oxaloacetate. Strikingly, an increased transcription of the anaerobic regulator gene anr correlates with the up-regulation of ANR-dependent genes. In conclusion, these changes in transcriptome and proteome indicate an adaptive shift towards constitutive expression of genes of metabolic pathways obviously required for growth under micro-aerobic and nutritional conditions of suppurative CF lung tissue. Finally, these results provide us with new targets for antimicrobial agents and biomarkers reflecting adaptation of PA towards progressive CF lung disease. Keywords: in vitro study/interstrain comparison/clinical isolates/early nonmutator vs. late mutator; variable time point of isolation from cf respiratory secretions
Project description:The Human Tracheal Gland (HTG) cell line MM39 and the CF HTG cell line CF-KM4 were incubated with or without a P. aeruginosa supernatant for 3 hours.
Project description:Pseudomonas aeruginosa (P. aeruginosa) lung infection is a significant cause of mortality in patients with cystic fibrosis (CF). Most CF patients acquire unique P. aeruginosa strains from the environment; however clonal strains have been identified in CF communities in several countries. Two clonal strains infect 10% to 40% of patients in three CF clinics in mainland eastern Australia. The expression profiles of four planktonically-grown isolates of one Australian clonal strain (AES-2), and four non–clonal CF P. aeruginosa isolates were compared to each other and to the reference strain PAO1 using the Affymetrix P. aeruginosa PAO1 genome array, to gain insight into properties mediating the enhanced infectivity of AES-1. The isolates were subsequently grown as 3-day old biofilms and similarly extracted for RNA and compared as above. Data analysis was carried out using BIOCONDUCTOR software. Keywords: Comparative strain hybridization