Project description:In the present study, we employed Affymetrix Pseudomonas aeruginosa GeneChip arrays to investigate global gene expression profiles during the cellular response of Pseudomonas aeruginosa to sodium hypochlorite Keywords: Antimicrobial response
Project description:Pseudomonas aeruginosa colonises the upper airway of cystic fibrosis (CF) patients, providing a reservoir of host-adapted genotypes that subsequently establish chronic lung infection. We previously experimentally-evolved P. aeruginosa in a murine model of respiratory tract infection and observed mutations in pmrB that promoted establishment and persistence of infection. Here we show that mutations in pmrB, which encodes the sensor kinase of the PmrAB two-component system, are acquired early in infection and increase resistance to the host antimicrobial lysozyme. Proteomic analysis of pmrB mutants reveal downregulation of proteins involved in LPS biosynthesis, antimicrobial resistance and phenazine production, and upregulation of proteins involved in adherence, lysozyme resistance and inhibition of the chloride ion channel CFTR, relative to wild-type strain LESB65. Accordingly, pmrB mutants show enhanced adherence to airway epithelial cells and downregulate host CFTR expression. P. aeruginosa pmrB mutations are found in CF patient isolates and are associated with the same phenotypes, but are subject to an evolutionary trade-off: enhanced colonisation potential, resistance to host defences and CFTR inhibition, but concomitant increased susceptibility to antibiotics.
Project description:Pseudomonas aeruginosa is a common bacteria leading to exacerbations of chronic obstructive pulmonary disease (COPD) patients while this bacteria can be easily eradicated by the immune systems of healthy individuals. Human airway organoids derived from healthy individuals and COPD patients were infected with pseudomonas aeruginosa. This project aims (1) to understand the differences in gene expressions in healthy and COPD airway organoids during stable condition, without infection and (2) to investigate differential pathogenic mechanism (i.e. antimicrobial defense) of pseudomonoas aeruginosa infection in healthy and COPD populations. Three healthy donors and three COPD patients were included in this study and samples were collected with and without pseudomonas aeruginosa infection.
Project description:Background: Pseudomonas aeruginosa often causes multidrug-resistant infections in immunocompromised patients and polymyxins are often used as the last-line therapy. Alarmingly, resistance to polymyxins has been increasingly reported worldwide recently. To rescue this last-resort class of antibiotics, it is necessary to systematically understand how P. aeruginosa alters its metabolism in response to polymyxin treatment, thereby facilitating the development of effective therapies. To this end, a genome-scale metabolic model (GSMM) was employed to analyse bacterial metabolic changes at the systems level. Findings: A high-quality GSMM iPAO1 was constructed for P. aeruginosa PAO1 for antimicrobial pharmacological research. Model iPAO1 encompasses an additional periplasmic compartment and contains 3,022 metabolites, 4,265 reactions and 1,458 genes in total. Growth prediction on 190 carbon and 95 nitrogen sources achieved an accuracy of 89.1%, outperforming all reported P. aeruginosa models. Notably, prediction of the essential genes for growth achieved a high accuracy of 87.9%. Metabolic simulation showed that lipid A modifications associated with polymyxin resistance exert a limited impact on bacterial growth and metabolism, but remarkably change the physiochemical properties of the outer membrane. Modelling with transcriptomics constraints revealed a broad range of metabolic responses to polymyxin treatment, including reduced biomass synthesis, upregulated amino acids catabolism, induced flux through the tricarboxylic acid cycle, and increased redox turnover. Conclusions: Overall, iPAO1 represents the most comprehensive GSMM constructed to date for Pseudomonas. It provides a powerful systems pharmacology platform for the elucidation of complex killing mechanisms of antibiotics.
Project description:Analysis of a SigX knockout mutant of Pseudomonas aeruginosa H103 strain in minimal medium with glucose as carbon source (M9G). SigX, one of the 19 extra-cytoplasmic function sigma factors of P. aeruginosa, was only known to be involved in transcription of the gene encoding the major outer membrane protein OprF in Pseudomonas aeruginosa. Deletion of the ECF sigma factor sigX gene provide insights into the SigX role in several virulence and biofilm- related phenotypes in Pseudomonas aeruginosa.
Project description:Purpose : The goal of this study was to use RNA Seq to explore the correlation of gene expression of a collection of clinical P. aeruginosa isolates to various phenotypes, such as antimicrobial resistance, biofilm formation or virulence Methods : mRNA profiles were generated for Pseudomonas aerugionsa clinical samples derived from various geographical locations by deep sequencing. The removal of ribosomal RNA was performed using the Ribo-Zero Bacteria Kit (Illumina) and cDNA libraries were generated with the ScriptSeq v2 Kit (Illumina) . The samples were sequenced in single end mode on an Illumina HiSeq 2500 device and mRNA reads were trimmed and mapped to the NC_008463.1 (PA14) reference genome from NCBI using Stampy pipeline with defaut settings.
Project description:The ParS/ParR two component regulatory system plays important roles for multidrug resistance in Pseudomonas aeruginosa. In this study we report RNA-seq analyses of the transcriptomes of P. aeruginosa PAO1 wild type and par mutants growing in a minimal medium containing 2% casamino acids. This has allowed the quantification of PAO1 transcriptome, and further defines the regulon that is dependent on the ParS/ParR system for expression. Our RNA-seq analysis produced the first estimates of absolute transcript abundance for the 5570 coding genes in P. aeruginosa PAO1. Comparative transcriptomics of P. aeruginosa PAO1 and par mutants identified a total of 464 genes regulated by ParS and ParR. Results also showed that mutations in the parS/parR system abolished the expression of the mexEF-oprN operon by down-regulating the regulatory gene mexS. In addition to affecting drug resistance genes, transcripts of quorum sensing genes (rhlIR and pqsABCDE-phnAB), were significantly up-regulated in both parS and parR mutants. Consistent with these results, a significant portion of the ParS/ParR regulated genes belonged to the MexEF-OprN and quorum sensing regulons. Deletion of par genes also lead to overproduction of phenazines and increased swarming motility, consistent with the up-regulation of quorum sensing genes. Our results established a link among ParS/ParR, MexEF-OprN and quorum sensing in Pseudomonas aeruginosa. Based on these results, we propose a model to illustrate the relationship among these regulatory systems in P. aeruginosa. A total of 9 samples were analyzed in AB medium + 2% casamino acids, Pseudomonas aeruginosa PAO1 wild type strain (3 replicates); Pseudomonas aeruginosa parS mutant (3 replicates); Pseudomonas aeruginosa parR mutant (3 replicates).