Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1252669 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Acinetobacter baumannii is often highly resistant to multiple antimicrobials, posing a risk of treatment failure. Colistin is often chosen as a “last resort” for treatment of the bacterial infection, but resistance is easily developed when the bacteria is exposed to the drug. Thus a comprehensive analysis of colistin-mediated changes in colistin-susceptible and colistin-resistant A. baumannii is needed. In this study, we used a colistin-susceptible A. baumannii clinical isolate and a colistin-resistant isogenic mutant. Whole genome sequencing revealed that the resistant isolate harbored a PmrBL208F mutation conferring colistin resistance, and all other single nucleotide alterations were located in intergenic regions. Using scanning electron microscopy, we observed that the colistin-resistant mutant had a shorter cell length than the parental isolate, and filamented cells were observed when both isolates were exposed to inhibitory concentration of colistin. When the isolates were treated with inhibitory concentrations of colistin, more than 80% of the genes were upregulated, including genes associated with antioxidative stress response pathways. This results helped a better understanding for the morphological difference between the colistin-susceptible and –resistant isolates and differed colistin-mediated responses in A. baumannii isolates by their susceptibility to this drug.
2025-05-02 | GSE267612 | GEO
Project description:Salmonella Heidelberg is currently the 9th common serovar and has more than twice the average incidence of blood infections in Salmonella. A recent Salmonella Heidelberg outbreak in chicken infected 634 people during 2013-2014, with a hospitalization rate of 38% and an invasive illness rate of 15%. While the company’s history suggested longstanding sanitation issues, the strains’ characteristics which may have contributed to the outbreak are unknown. We hypothesized that the outbreak strains of S. Heidelberg might possess enhanced stress tolerance or virulence capabilities. Consequently, we obtained nine food isolates collected during the outbreak investigation and several reference isolates and tested their tolerance to processing stresses, their ability to form biofilms, and their invasiveness in vitro. We further performed RNA-sequencing on three isolates with varying heat tolerance to determine the mechanism behind our isolates’ enhanced heat tolerance. Ultimately, we determined that (i) many Salmonella Heidelberg isolates associated with a foodborne outbreak have enhanced heat resistance (ii) Salmonella Heidelberg outbreak isolates have enhanced biofilm-forming ability under stressful conditions, compared to the reference strain (iii) exposure to heat stress may also increase Salmonella Heidelberg isolates’ antibiotic resistance and virulence capabilities and (iv) Salmonella Heidelberg outbreak-associated isolates are primed to better survive stress and cause illness. This data helps explain the severity and scope of the outbreak these isolates are associated with and can be used to inform regulatory decisions on Salmonella in poultry and to develop assays to screen isolates for stress tolerance and likelihood of causing severe illness.
2018-09-01 | GSE103418 | GEO
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.
2018-02-19 | GSE107964 | GEO
Project description:The transcriptional, epigenomic, and genomic profiles of K. pneumoniae isolates were characterised to identify novel colistin and carbapenem resistance mechanisms. The genomic DNA and total RNA of the isolates were isolated and sequenced on PacBio.
2022-11-07 | GSE217148 | GEO
Project description:Salmonella infections are among the most common foodborne diseases worldwide. The Enteritidis and Dublin serovars of Salmonella enterica are closely related yet they differ significantly in pathogenicity and epidemiology. Enteritidis is a broad-host-range serovar that commonly causes gastroenteritis and infrequently causes invasive disease in humans. Dublin mainly colonizes cattle but upon infecting humans often results in invasive disease. The aim of this work was to elucidate the molecular factors responsible for the differential pathogenic behavior between both serovars. We performed a quantitative proteomic comparative analysis between one clinical isolate of each serovar grown in vitro under gut mimicking conditions (GMC). Compared to S. Enteritidis, the S. Dublin proteome was enriched in proteins linked to response to several stress conditions, such as those encountered during host infection, as well as to virulence. The S. Enteritidis proteome contained proteins related to central anaerobic metabolism pathways that were undetected in S. Dublin. Similar differences were also found at the transcriptional level, as mRNA levels correlated with proteomic results for 17 of the 20 genes tested in 4 natural isolates of each serovar grown in GMC. This work reveals proteomic differences between two Salmonella serovars with markedly different invasive and host-range characteristics, grown in an infection relevant condition, which were not evident in previous comparative genomic analyses.
2021-09-09 | PXD021353 | Pride
Project description:E.coli and Salmonella colistin resistance
| PRJEB18587 | ENA
Project description:In past, resistance mechanisms have been identified by analysis of resistant isolates or defined mutants. Recently, high-throughput transposon mutagenesis coupled with sequencing (TraDIS-Xpress) is another approach proving useful for elucidating the roles of genes involved in the overall cellular response to a particular stress. In this study, we used TraDIS-Xpress to determine the role played by genes following exposure to colistin stress. Approximately 10^7 cells from the mutant library were inoculated into LB broth at a range of doubling concentrations of colistin ( 0.25 x MIC, 0.5 x MIC, 1 x MIC, 2 X MIC). Experiments were performed with no induction, or with induction using 0.2 or 1 mM of Isopropyl β-D-1-thiogalactopyranoside (IPTG). All experiments were performed in duplicate.
2022-06-09 | E-MTAB-11807 | biostudies-arrayexpress
Project description:The study aimed to characterize plasmids mediating carbepenem resistance in Klebsiella pneumoniae in Pretoria, South Africa. We analysed 56 K. pneumoniae isolates collected from academic hospital around Pretoria. Based on phenotypic and molecular results of these isolates, 6 representative isolates were chosen for further analysis using long reads sequencing platform. We observed multidrug resistant phenotype in all these isolates, including resistance to aminoglycosides, tetracycline, phenicol, fosfomycin, floroquinolones, and beta-lactams antibiotics. The blaOXA-48/181 and blaNDM-1/7 were manily the plasmid-mediated carbapenemases responsible for carbapenem resistance in the K. pneumoniae isolates in these academic hospitals. These carbapenemase genes were mainly associated with plasmid replicon groups IncF, IncL/M, IncA/C, and IncX3. This study showed plasmid-mediated carbapenemase spread of blaOXA and blaNDM genes mediated by conjugative plasmids in Pretoria hospitals.
2019-10-17 | GSE138949 | GEO