Characterization of third-generation cephalosporin-resistant Escherichia coli from bloodstream infections in Denmark

Microb Drug Resist. 2014 Aug;20(4):316-24. doi: 10.1089/mdr.2013.0157. Epub 2014 Feb 11.

Abstract

The aim of the study was to investigate the molecular epidemiology of 87 third-generation cephalosporin-resistant Escherichia coli (3GC-R Ec) from bloodstream infections in Denmark from 2009. Sixty-eight of the 87 isolates were extended-spectrum beta-lactamase (ESBL) producers, whereas 17 isolates featured AmpC mutations only (without a coexpressed ESBL enzyme) and 2 isolates were producing CMY-22. The majority (82%) of the ESBL-producing isolates in our study were CTX-M-15 producers and primarily belonged to phylogroup B2 (54.4%) or D (23.5%). Further, one of the two CMY-22-producing isolates belonged to B2, whereas only few of the other AmpCs isolates belonged to B2 and D. Pulsed-field gel electrophoresis revealed that both clonal and nonclonal spread of 3GC-R Ec occurred. ST131 was detected in 50% of ESBL-producing isolates. The remaining ESBL-producing isolates belonged to 17 other sequence types (STs), including several other internationally spreading STs (e.g., ST10, ST69, and ST405). The majority (93%) of the ESBL-producing isolates and one of the CMY-22-producing isolates were multiresistant. In conclusion, 3GC-R in bacteriaemic E. coli in Denmark was mostly due to ESBL production, overexpression of AmpC, and to a lesser extent to plasmid-mediated AmpC. The worldwide disseminated CTX-M-15-ST131 was strongly represented in this collection of Danish, bacteriaemic E. coli isolates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / therapeutic use
  • Bacteremia / drug therapy
  • Bacteremia / epidemiology*
  • Bacteremia / microbiology
  • Cephalosporins / therapeutic use
  • Denmark / epidemiology
  • Electrophoresis, Gel, Pulsed-Field
  • Escherichia coli / drug effects
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Escherichia coli Infections / drug therapy
  • Escherichia coli Infections / epidemiology*
  • Escherichia coli Infections / microbiology
  • Female
  • Gene Expression
  • Hospitals
  • Humans
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Multilocus Sequence Typing
  • Plasmids
  • beta-Lactam Resistance*
  • beta-Lactamases / genetics*
  • beta-Lactamases / metabolism

Substances

  • Anti-Bacterial Agents
  • Cephalosporins
  • Isoenzymes
  • beta-Lactamases