Project description:This study identified and compared the bacterial diversity and the antimicrobial resistance profile of clinically relevant isolates around a newly developed hospital and university precinct
Project description:New and rapid antimicrobial susceptibility/resistance testing methods are required for bacteria from positive blood cultures. In the current study we developed and evaluated a targeted LC-MS/MS assay for the detection of beta-lactam, aminoglycoside and fluoroquinolone resistance mechanisms in blood cultures positive for E. coli or K. pneumoniae. Selected targets were the beta-lactamases SHV, TEM, OXA-1-like, CTX-M-1-like, CMY-2-like, chromosomal E. coli AmpC, OXA-48-like, NDM, VIM and KPC, the aminoglycoside modifying enzymes AAC(3)-Ia, AAC(3)-II, AAC(3)-IV, AAC(3)-VI, AAC(6’)-Ib, ANT(2”)-I and APH(3’)-VI, the 16S-RMTases ArmA, RmtB, RmtC and RmtF, the quinolone resistance mechanisms QnrA, QnrB, AAC(6’)-Ib-cr, the wildtype QRDR of GyrA, and for E. coli, the porins OmpC and OmpF. The developed assay was evaluated using 100 prospectively collected positive blood cultures, 100 negative blood cultures inoculated with isolates that were previously collected from blood cultures, and 48 isolates inoculated with isolates carrying genes of less prevalent resistance mechanisms.
Project description:A collection of 61 Salmonella enterica serovar Typhimurium (S. Typhimurium) of animal and human origin, matched as closely as possible by phage type, antimicrobial resistance pattern and place / time of isolation, and sourced from farms or hospitals in Scotland, were analysed by antimicrobial susceptibility testing, phage typing, pulsed field gel electrophoresis (PFGE), plasmid profiling and DNA microarrays. PFGE of all 61 isolates revealed ten PFGE profiles, which clustered by phage type and antibiotic resistance pattern, with human and animal isolates distributed between PFGE profiles. Analysis of 23 representative S. Typhimurium strains hybridised to a composite Salmonella DNA microarray identified a small number of specific regions of genome variation between different phage types and PFGE profiles. These variable regions of DNA were typically located within prophage-like elements. Simple PCR assays were subsequently designed to discriminate between different isolates from the same geographical region.
2007-06-09 | E-SGRP-6 | biostudies-arrayexpress
Project description:Antimicrobial Susceptibility in Historical C. difficile Isolates
Project description:Investigation of the phylogenetic diversity of Acidobacteria taxa using PCR amplicons from positive control 16S rRNA templates and total genomic DNA extracted from soil and a soil clay fraction
Project description:Here, we analyzed 76 ecologically diverse wild yeast isolates and discovered a wide diversity of replicative lifespan. Phylogenetic analyses pointed to genes and environmental factors that strongly interact to modulate the observed aging patterns. We then identified genetic networks causally associated with natural variation in replicative lifespan across wild yeast isolates, as well as genes, metabolites and pathways, many of which have never been associated with yeast lifespan in laboratory settings. In addition, a combined analysis of lifespan-associated metabolic and transcriptomic changes revealed unique adaptations to interconnected amino acid biosynthesis, glutamate metabolism and mitochondrial function in long-lived strains. Overall, our multi-omic and lifespan analyses across diverse isolates of the same species shows how gene-environment interactions shape cellular processes involved in phenotypic variation such as lifespan.
2021-11-07 | GSE188294 | GEO
Project description:Antimicrobial resistance and virulence characteristics of Klebsiella isolates in Kenya
Project description:Cationic antimicrobial peptides (CAPs) are promising novel alternatives to conventional antibacterial agents, but the overlap in resistance mechanisms between small-molecule antibiotics and CAPs is unknown. Does evolution of antibiotic resistance decrease (cross-resistance) or increase (collateral sensitivity) susceptibility to CAPs? We systematically addressed this issue by studying the susceptibilities of a comprehensive set of antibiotic resistant Escherichia coli strains towards 24 antimicrobial peptides. Strikingly, antibiotic resistant bacteria frequently showed collateral sensitivity to CAPs, while cross-resistance was relatively rare. We identified clinically relevant multidrug resistance mutations that simultaneously elevate susceptibility to certain CAPs. Transcriptome and chemogenomic analysis revealed that such mutations frequently alter the lipopolysaccharide composition of the outer cell membrane and thereby increase the killing efficiency of membrane-interacting antimicrobial peptides. Furthermore, we identified CAP-antibiotic combinations that rescue the activity of existing antibiotics and slow down the evolution of resistance to antibiotics. Our work provides a proof of principle for the development of peptide based antibiotic adjuvants that enhance antibiotic action and block evolution of resistance.
