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PROVIDER: PRJNA1178171 | ENA |
REPOSITORIES: ENA
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Project description:Purpose: The goal of this study was to elucidate the collateral effects associated with OXA-23 overexpression on the Acinetobacter baumannii global transcriptome. Results: Besides the 99.73-fold increase in blaOXA-23 transcript upon IPTG induction, no other transcripts showed more than a 2-fold change compared to the wildtype control. This suggests that OXA-23 over expression to levels similarly observed in multi drug resistant A. baumannii clinical isolates does not effect the transcriptome.
2021-11-15 | GSE185203 | GEO
Project description:Infections caused by carbapenem-resistant Acinetobacter baumannii (CRAb) are associated with high patient morbidity and mortality. The serious threat for human health imposed by CRAb was recently underscored by identification of close-to-untouchable carbapenem- and tetracycline-resistant isolates. Since outer membrane vesicles (OMVs) of Gram-negative bacteria may contribute to antimicrobial resistance, our present study was aimed at investigating OMVs produced by the first two carbapenem- and tetracycline-resistant CRAb isolates in Europe. These isolates, denoted CRAb1 and CRAb2 contain large, nearly identical plasmids that specify multiple resistances. Both isolates produce OMVs that were analyzed by differential light scattering, transmission electron microscopy and proteomics. By comparison with OMVs from the plasmid-free non-carbapenem-resistant A. baumannii isolate Ab1, which is an isogenic ancestor of the CRAb1 isolate, we show that plasmid carriage by the CRAb1 and CRAb2 isolates leads to an increased OMV size that is accompanied by increased diversity of the OMV proteome. Our analyses show that OMVs from CRAb1 and CRAb2 are major reservoirs of proteins involved in antimicrobial resistance, including the plasmid-encoded carbapenemases BlaNDM-1, and BlaOXA-97. We also show that these OMV-borne carbapenemases hydrolyze imipenem and protect otherwise carbapenem-sensitive A. baumannii and Escherichia coli isolates against this antibiotic. Altogether, our observations show that OMVs from highly drug-resistant CRAb confer tolerance against last-resort antibiotics to non-resistant bacterial pathogens.
2025-04-14 | PXD051698 | Pride
Project description:Cefiderocol (CFDC) is a novel chlorocatechol-substituted siderophore approved to treat complicated urinary tract infections and for hospital-acquired and ventilator-acquired pneumonia. In previous work, human fluids, were shown to increase the minimum inhibitory concentration (MICs) of Acinetobacter baumannii against CFDC and reduce the expression of genes related to iron uptake systems, which could explain the need for higher concentrations of CFDC to exert inhibitory action. Herein, we analyzed the impact of human urine (HU), which contains low albumin concentrations, on the expression of iron-uptake related genes and MIC values of two carbapenem-resistant A. baumannii. Levels of resistance to CFDC were not modified by HU in strain AMA40 but were reduced in the case of strain AB5075. Testing other carbapenem-resistant A. baumannii isolates showed that the CFDC MICs were unmodified or reduced in the presence of HU. The expression of piuA, pirA, bauA, and bfnH determined by qRT-PCR was enhanced in both strains when HU was present in the culture medium. All four tested genes are involved in recognizing ferric siderophore complexes or internalization into the cell’s cytosol. In contrast, the effect of HU on genes associated with resistance to β-lactams, antibiotics commonly used to treat urinary tract infections caused by A. baumannii, was variable; the transcriptional analysis of pbp1, pbp3, blaOXA-51-like, blaADC, and blaNDM-1 showed significant variation. In summary, HU, probably due to the albumin and free iron content, does not adversely impact or slightly improves the activity of CFDC when tested against A. baumannii in urine in contrast to other human bodily fluids.
2022-06-01 | GSE201259 | GEO
Project description:This study examined the response of A. baumannii to cspC disruption via transposon mutagenesis. The goal was to gain insight into how a cold shock protein highly expressed within A. baumannii biofilms, CspC, functioned and identify pathways in which it may be involved.
2021-05-12 | GSE164290 | GEO
Project description:The nosocomial pathogen Acinetobacter baumannii is a frequent cause of hospital acquired infections worldwide, and a challenge for treatment due to its evolved resistance to antibiotics, including carbapenems. To gain insight on A. baumannii antibiotic resistance mechanisms, we analyzed the protein interaction network of a multidrug-resistant A. baumannii clinical strain Ab5075. Using in vivo chemical cross-linking and mass spectrometry, we identified 2,068 non-redundant cross-linked peptide pairs containing 245 intra- and 398 inter- molecular interactions. Outer membrane proteins OmpA and YiaD, and carbapenemase Oxa-23 are hubs of the identified interaction network. Eighteen novel interactors of Oxa-23 were identified. Interactions of Oxa-23 with outer membrane porins OmpA and CarO were verified with co-immunoprecipitation analysis. Furthermore, transposon mutagenesis of oxa-23 or interactors of Oxa-23 demonstrated changes in meropenem or imipenem sensitivity in Ab5075. These results provide the first view of a porin-localized toxin inactivation model and increase understanding of bacterial antibiotic resistance mechanisms.
2016-12-22 | PXD004236 | Pride
Project description:lpsB encodes a glycosyltransferase involved in lipopolysaccharide (LPS) synthesis. LPS is a major component of the Gram-negative bacterial outer membranes. We used custom-made Affymetrix A. baumannii strain ATCC 17978 derived GeneChips to compare the gene expression properties of wild type and isogenic lpsB mutant cells. Two mutants were evaluated; A. baumannii strain 5A7 is a ATCC 17978 derivative harboring a transposon (Tn5) within lpsB (A1S_0430 locus); A. baumannii strain containing a deletion of lpsB (A1S_0430).
2012-12-01 | GSE40771 | GEO
Project description:lpsB encodes a glycosyltransferase involved in lipopolysaccharide (LPS) synthesis. LPS is a major component of the Gram-negative bacterial outer membranes. We used custom-made Affymetrix A. baumannii strain ATCC 17978 derived GeneChips to compare the gene expression properties of wild type and isogenic lpsB mutant cells. Two mutants were evaluated; A. baumannii strain 5A7 is a ATCC 17978 derivative harboring a transposon (Tn5) within lpsB (A1S_0430 locus); A. baumannii strain containing a deletion of lpsB (A1S_0430). A. baumannii strain ATCC 17978, 5A7 (lpsB:Tn5) or IH1∆lpsB (∆lpsB) were grown to mid-exponential phase growth, total bacterial RNA was isolated and subjected to GeneChip hybridization and analysis. We sought to determine the transcription profile of lpsB mutated cells.
2012-12-01 | E-GEOD-40771 | 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