High Prevalence of CTX-M Beta-Lactamases in Enterobacteriaceae from Healthy Individuals in Guangzhou, China

Microb Drug Resist. 2015 Aug;21(4):398-403. doi: 10.1089/mdr.2014.0201. Epub 2015 Mar 10.

Abstract

This study aimed to determine the prevalence of extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae and to characterize the genetic composition of ESBL determinants among Enterobacteriaceae isolates from healthy people in Guangzhou, China. A total of 200 rectal swab samples were collected from healthy asymptomatic individuals and tested for ESBL production using ChromID ESBL agar. Phenotypic ESBL producers were screened for blaCTX-M, blaTEM, and blaSHV genes using PCR and DNA sequencing. The prevalence of ESBL-producing Enterobacteriaceae among rectal swab samples was 69.5%. All ESBL-producing isolates harbored blaCTX-M genes (n=138) except for one isolate that harbored blaSHV-2a. Eleven CTX-M ESBL genes were detected. The most predominant CTX-M-type genes were blaCTX-M-14 (n=82), followed by blaCTX-M-55 (n=19), blaCTX-M-65 (n=10), and blaCTX-M-27 (n=9). Isolates carrying blaCTX-M-38,-3,-15,-14b,-98,-121 and -123 were also identified. Molecular homology analysis of the selected isolates was performed by phylogenetic grouping and multilocus sequence typing and indicated that the predominant clone belonged to A-CC10. This study showed a high rate of CTX-M-type ESBL genes among Enterobacteriaceae isolates from healthy individuals in China.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Anti-Bacterial Agents / pharmacology
  • China / epidemiology
  • DNA, Bacterial / genetics
  • Enterobacteriaceae / enzymology*
  • Female
  • Genotype
  • Healthy Volunteers
  • Humans
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Polymerase Chain Reaction
  • Prevalence
  • Public Health Surveillance
  • Rectum / microbiology
  • Young Adult
  • beta-Lactamases / genetics*

Substances

  • Anti-Bacterial Agents
  • DNA, Bacterial
  • beta-Lactamases