Project description:The present study examines changes in global gene expression patterns and in virulence factor-associated genes in an extended spectrum beta-lactamase (ESBL)-producing UPEC (ESBL019) during the morphologic transitions induced by an ineffective antibiotic and in the presence of human primary bladder epithelial cells. The morphological shifts induced by ineffective antibiotics are associated with significant transcriptional virulence alterations in ESBL-producing UPEC, which may affect survival and persistence in the urinary tract. Overall design: Changes in global gene expression patterns and in virulence factor-associated genes in an extended spectrum beta-lactamase (ESBL)-producing UPEC (ESBL019) during the morphologic transitions induced by an ineffective antibiotic (ceftibuten) in the presence of human primary bladder epithelial cells was evaluated by microarray after 4 hours. Four different morphologies were studied; Coliform, Transition (from Coli into Filamented), Filamented and Reverted (reverted back from a Filamented shape into a coli shape). Four independent experiments were included in each group.
| GSE99661 | GEO
Project description:Mcr-1 encoding isolates from food
Project description:Treatment of urinary tract infections is today a challenge due to the increasing prevalence of multidrug-resistant ESBL-producing uropathogenic Escherichia coli (UPEC). There is an urgent need for new treatment strategies for multidrug-resistant UPEC and preferably with targets that have low potential for development of resistance. Carbon monoxide-releasing molecules (CORMs) are novel and potent antibacterial agents. The present study examines the transcriptomic targets of CORM-2 in a multidrug-resistant ESBL-producing UPEC isolate (ESBL7) in response to a single exposure to CORM-2 and after repeated exposure to CORM-2. The bacterial viability and minimal inhibitory concentration (MIC) were also examined after repeated exposure to CORM-2. Microarray analysis revealed that a wide range of processes were affected by CORM-2, including a general trend of down-regulation in energy metabolism and biosynthesis pathways and up-regulation of the SOS response and DNA repair. Several genes involved in virulence (ibpB), antibiotic resistance (marAB, mdtABC) and biofilm formation (bhsA, yfgF) were up-regulated, while some genes involved in virulence (kpsC, fepCEG, entABE), antibiotic resistance (evgA) and biofilm formation (artIP) were down-regulated. Repeated exposure to CORM-2 did not alter the gene expression patterns, the growth inhibitory response to CORM-2 or the MIC values for CORM-2, cefotaxime, ciprofloxacin and trimethoprim. Overall design: ESBL7 from the original isolate, or isolates pre-exposed 20 times to CORM-2 (250 µM) or vehicle (2.5% DMSO) for 4 hours at 37 °C, were used to inoculate MS-medium followed by exposure to CORM-2 (250 µM) or vehicle for 30 min at 37 °C. Microarray were performed on first exposure to sub-inhibitory levels of CORM-2 (250 µM), first exposure to vehicle (2.5% DMSO), pre-exposed 20 times to CORM-2 respectively pre-exposed 20 times to vehicle. Four independent experiments were included in each group.
Project description:Colistin is a crucial last-line drug used for the treatment of life-threatening infections caused by multi-drug resistant strains of the Gram-negative bacteria, Acinetobacter baumannii. However, colistin resistant A. baumannii isolates can be isolated following failed colistin therapy. Resistance is most often mediated by the addition of phosphoethanolamine (pEtN) to lipid A by PmrC, following missense mutations in the pmrCAB operon encoding PmrC and the two-component signal transduction system PmrA/PmrB. We recovered an isogenic pair of A. baumannii isolates from a single patient before (6009-1) and after (6009-2) failed colistin treatment that displayed low/intermediate and high levels of colistin resistance, respectively. To understand how increased colistin-resistance arose, we genome sequenced each isolate which revealed that 6009-2 had an extra copy of the insertion sequence element ISAba125 within a gene encoding an H-NS-family transcriptional regulator. Consequently, transcriptomic analysis of the clinical isolates identified was performed and more than 150 genes as differentially expressed in the colistin-resistant, hns mutant, 6009-2. Importantly, the expression of eptA, encoding a second lipid A-specific pEtN transferase, but not pmrC, was significantly increased in the hns mutant. This is the first time an H-NS-family transcriptional regulator has been associated with a pEtN transferase and colistin resistance. Overall design: mRNA profiles of two isolates taken from a single patient, one before and one after colistin treatment, cDNA libraries were sequenced on an Illumina HiSeq 2000
Project description:This project has two goals. Firstly, to compare the gene expression profiles of Caco cells following exposure to Verocytotoxigenic E. coli0157:H7 (VTEC) isolates from food animals (bovine, ovine, porcine) and human in an effort to assess the invasive and toxigenic potential of isolates of different origin. All sources contain the common virulence and type 3 secretory system genes. Secondly, to compare the gene expression profiles of Caco-2 cells following exposure to VTEC isolates that contain (positive) or do not contain (negative) the genes of the type 3 secretory system (TTSS). Overall design: Eight groups (TTSS positive), four replicates (32 arrays in total):1. Control x 4, 2. Human x 4, 3. Ovine x 4, 4. Bovine x 4, 5. Porcine x 4, 6. International Reference x 4, 7. TTSS_NEG_Human x 4, 8.TTSS_NEG_Ovine x 4
Project description:The goal of this study is the discovery of (a) meaningful phylogenomic relationships among members of this B. cereus/B. anthracis group, and (b) reliable gene-phenotype associations, e.g. recognition of links between genomic traits and the ability of certain strains to cause various forms of disease. We also tried to elucidate genome evolution aspects that may lead to the emergence of variants that are capable (or have the potential) of causing anthrax-like disease. This large-scale comparative genomics approach is unprecedented for this taxonomic group. Dr. A. Hoffmaster (CDC) provided the PFGRC with 73 B. cereus and B. anthracis isolates from the CDC culture collection. Of these, 27 were isolated from patients with severe or systemic disease; ten isolates of this group were obtained from patients (welding factory workers) with anthrax-like disease or from the environment near their workplace. Another set of 26 represented isolates from food-born illnesses. Of the 26 gastrointestinal disease isolates (GIDI), 10 were obtained from patients with diarrhea, whereas another set of 10 had been shown to harbor the emetic (vomit) toxin gene by PCR. The rest of the group consisted of 20 isolates with various phenotypes. All strains were screened for their genomic content using the B. cereus/B. anthracis species microarray. Overall design: Seventy-three query strains were investigated in this study, with each query strain hybridized against the reference strain, Sterne. Dye-swap experiments were performed with all the 73 strains on both chipA and chipB of the microarray, for a total of four or more hybridizations per query strain. Each 70mer oligo spotted on the B. cereus species microarray is spotted once. Positive controls on the array consist of oligos designed from the sequenced reference genome, Sterne, and negative controls on the array consist of oligos designed from the thale cress plant, Arabidopsis thaliana.