Escherichia coli
Mechanisms of ResistanceUpregulation of PBP1B and LpoB in cysB Mutants Confers Mecillinam (Amdinocillin) Resistance in Escherichia coliMecillinam (amdinocillin) is a β-lactam antibiotic that inhibits the essential penicillin-binding protein 2 (PBP2). In clinical isolates of Escherichia coli from urinary tract infections, inactivation of the cysB gene (which encodes the main regulator of cysteine biosynthesis, CysB) is the major cause of resistance. How a nonfunctional CysB protein confers...
Mechanisms of Resistancemcr-9, an Inducible Gene Encoding an Acquired Phosphoethanolamine Transferase in Escherichia coli, and Its OriginThe plasmid-located mcr-9 gene, encoding a putative phosphoethanolamine transferase, was identified in a colistin-resistant human fecal Escherichia coli strain belonging to a very rare phylogroup, the D-ST69-O15:H6 clone. This MCR-9 protein shares 33% to 65% identity with the other plasmid-encoded MCR-type enzymes identified (MCR-1 to -8) that have been found...
Mechanisms of ResistancePlasmid-Mediated mcr-1 Colistin Resistance in Escherichia coli from a Black Kite in RussiaThe gene mcr-1 conferring resistance to last-line antibiotic colistin has been reported globally. Here, we describe the first detection of plasmid-mediated colistin resistance in Russian wildlife, an isolate of Escherichia coli sequence type 2280 from a black kite (Milvus migrans) scavenging raptor. Whole-genome sequencing and plasmid transferability...
Mechanisms of ResistanceMultiple Copies of qnrA1 on an IncA/C2 Plasmid Explain Enhanced Quinolone Resistance in an Escherichia coli MutantIn a previous study, mutants with enhanced ciprofloxacin resistance (Cipr) were selected from Escherichia coli J53/pMG252 carrying qnrA1. Strain J53 Cipr 8-2 showed an increase in the copy number and transcription level of qnrA1. We sequenced the plasmids on Illumina and MinION platforms.
Mechanisms of ResistanceRapid Increase in Carbapenemase-Producing Enterobacteriaceae in Retail Meat Driven by the Spread of the blaNDM-5-Carrying IncX3 Plasmid in China from 2016 to 2018The presence and molecular characteristics of carbapenemase-producing Enterobacteriaceae (CPE) among meat products in China were investigated. A total of 110 carbapenem-resistant Enterobacteriaceae (CRE) isolates, including 94 ...
Experimental TherapeuticsUnexpected Activity of Oral Fosfomycin against Resistant Strains of Escherichia coli in Murine PyelonephritisFosfomycin tromethamine activity is well established for oral treatment of uncomplicated lower urinary tract infections, but little is known about its potential efficacy in pyelonephritis. Ascending pyelonephritis was induced in mice infected with 6 strains of Escherichia coli (fosfomycin MICs, 1 μg/ml to 256 μg/ml). The urine pH was 4.5 before infection and 5.5 to 6....
Epidemiology and SurveillanceThe Arginine Deiminase Operon Is Responsible for a Fitness Trade-Off in Extended-Spectrum-β-Lactamase-Producing Strains of Escherichia coliWe previously identified an operon involved in an arginine deiminase (ADI) pathway (arc operon) on a CTX-M-producing plasmid from an O102-ST405 strain of Escherichia coli. As the ADI pathway was shown to be involved in the virulence of various Gram-positive bacteria, we tested whether the ADI pathway could be involved in the epidemiological success of...
Epidemiology and SurveillanceJoint Modeling of Resistance to Six Antimicrobials in Urinary Escherichia coli Isolates in Quebec, CanadaEmpirical treatment of urinary tract infections should be based on susceptibility profiles specific to the locale and patient population. Additionally, these susceptibility profiles should account for correlations between resistance to different types of antimicrobials.
Mechanisms of ResistanceFate of CMY-2-Encoding Plasmids Introduced into the Human Fecal Microbiota by Exogenous Escherichia coliThe gut is a hot spot for transfer of antibiotic resistance genes from ingested exogenous bacteria to the indigenous microbiota. The objective of this study was to determine the fate of two nearly identical blaCMY-2-harboring plasmids introduced into the human fecal microbiota by two Escherichia coli strains isolated from a human and from poultry...
