Dissemination of CTX-M-3 and CMY-2 beta-lactamases among clinical isolates of Escherichia coli in southern Taiwan

J Clin Microbiol. 2000 Dec;38(12):4320-5. doi: 10.1128/JCM.38.12.4320-4325.2000.

Abstract

A total of 1,210 clinical isolates of Escherichia coli collected from a university hospital in southern Taiwan were screened for production of extended-spectrum beta-lactamases (ESBLs). Expression of classical ESBLs (resistant to extended-spectrum beta-lactam agents and susceptible to beta-lactam inhibitors) was inferred in 18 isolates by the phenotypic confirmatory test. These included 10 isolates producing CTX-M-3, 2 strains carrying SHV-12, 1 strain harboring SHV-5, 1 strain expressing TEM-10, and 4 strains producing unidentifiable ESBLs with a pI of 8.05, 8.0, or 7.4. Eighteen isolates that showed decreased susceptibilities to ceftazidime and/or cefotaxime, negative results for the confirmatory test, and high-level resistance to cefoxitin (MICs of >/=128 microg/ml) were also investigated. Five isolates were found to produce CMY-2 AmpC enzymes, one isolate carried both CTX-M-3 and CMY-2, and the remaining three and nine isolates expressed putative AmpC beta-lactamases with pIs of >9.0 and 8.9, respectively. Thus, together with the isolate producing CTX-M-3 and CMY-2, 19 (1.6%) isolates produced classical ESBLs. Pulsed-field gel electrophoresis revealed that all isolates carrying CTX-M-3 and/or CMY-2 were genetically unrelated, indicating that dissemination of resistance plasmids was responsible for the spread of these two enzymes among E. coli in this area. Among the 16 isolates expressing CTX-M-3 and/or CMY-2, 5 might have colonized outside the hospital environment. Our data indicate that CTX-M-3 and CMY-2, two beta-lactamases initially identified in Europe, have been disseminated to and are prevalent in Taiwan.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Child, Preschool
  • Cross Infection / microbiology
  • Drug Resistance, Microbial
  • Escherichia coli / drug effects
  • Escherichia coli / enzymology*
  • Escherichia coli Proteins
  • Female
  • Humans
  • Isoelectric Focusing
  • Male
  • Middle Aged
  • Polymerase Chain Reaction
  • R Factors
  • beta-Lactamases / biosynthesis*
  • beta-Lactamases / genetics

Substances

  • Escherichia coli Proteins
  • beta-lactamase CMY-2
  • beta-Lactamases
  • beta-lactamase CMY-2, E coli