title: Prevalence characterization of extended-spectrum beta-lactamases among Escherichia coli isolates collected in Zhengzhou.
abstract: OBJECTIVE
  To determine the prevalence and the diversity of extended-spectrum beta-lactamases (ESBLs) among Escherichia coli isolates in Zhengzhou, China.
  
  
  METHODS
  Clinical isolates were collected and investigated from the first affiliated hospital of Zhengzhou University and its associated health-care facilities in Zhengzhou, China, during the period from January 2006 to June 2008. Antibiograms were performed on Mueller-Hinton agar plates with the disc-diffusion method and MICs were determined by the agar-dilution method. Total DNA was extracted with a Qiagen mini kit and screened by PCR.
  
  
  RESULTS
  Of 94 nonduplicate ESBL-positive isolates, TEM-type was encoded in 74 and 79% of the ESBL isolates. Fifty-six isolates were SHV type ESBLs. CTX-M-1, CTX-M-14, CTX-M-25, and CTX-M-38 types were encoded in 30, 54, 6, and 4, respectively. OXA-1-type beta-lactamases were encoded in six and OXA-20-type was encoded in two isolates.
  
  
  CONCLUSIONS
  We describe a complex ESBL epidemiology. The study revealed a high rate of ESBL-producing E. coli isolates. TEM and CTX-M enzymes dominated in ESBL-positive E. coli isolates in Zhengzhou, China.
authors.affiliation: The Third Affiliated Hospital, Zhengzhou University, Zhengzhou, China.
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Guo
authors.forename: Qinxian
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D002681:China; D004587:Electrophoresis, Agar Gel; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000032:analysis / Q000235:genetics*
chemical_list: D001618:beta-Lactamases