title: Antimicrobial resistance, genotypic characterization and pulsed-field gel electrophoresis typing of extended spectrum β-lactamases-producing clinical Escherichia coli strains in Macao, China.
abstract: BACKGROUND
  The rise of the production of CTX-M class extended spectrum β-lactamases (ESBLs) has been well documented in traveling countries but no data are found for Macao, an international travel city. The objectives of this study were to identify the antimicrobial resistance pattern, and determine the prevalence, genotype and clonal relationship of ESBLs in 209 clinical Escherichia coli strains from Macao, China.
  
  
  METHODS
  Antimicrobial susceptibility test was performed to determine the resistance patterns of the isolates using the disk diffusion method with 17 antimicrobial agents. Phenotypic detection was screened and confirmed according to the Clinical and Laboratory Standards Institute. Genotypic characterization was detected by isoelectric focusing analysis, polymerase chain reaction and sequencing. The clonal relationship between the different ESBL isolates was studied by pulsed-field gel electrophoresis (PFGE).
  
  
  RESULTS
  Imipenem and meropenem exhibited 100% susceptible among 209 strains. Overall, 82.3%, 67.3%, 52.9%, 51.2% and 51.0% of the isolates displayed resistance to ampicillin, tetracycline, ciprofloxacin, sulfamethoxazole trimethoprim and gentamycin. The prevalence rate of ESBLs was 30.1%. Antibiotic resistances were found to be significantly higher among the ESBL producing group compared to non-ESBL producing group. We detected CTX-M-14 to be the major genotypic characterization of ESBLs (76.2%). Two strains showed indistinguishable patterns by PFGE.
  
  
  CONCLUSIONS
  The prevalence of antimicrobial resistance is alarming high in Macao. Antimicrobial resistance is significantly higher among the ESBL producing group. This study documented CTX-M-14 as the predominant ESBL type. Although indistinguishable pattern was found between two strains, it was too small to decide whether any of the investigated strains was epidemic. Our findings may be also pertinent for other geographic areas undergoing similar travel characteristics to understand the corresponding effects on bacterial populations.
authors: School of Health Sciences, Macao Polytechnic Institute, Macao Special Administrative Region (SAR), China. yeqianhong@ipm.edu.mo
authors: Qian-hong
authors: QH
authors: Ye
authors: Ying
authors: Y
authors: Lau
authors: Bin
authors: B
authors: Liang
authors: Su-fei
authors: SF
authors: Tian
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D002681:China; D004352:Drug Resistance, Microbial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods*; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D005838:Genotype; D007525:Isoelectric Focusing; D008256:Macau; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000890:Anti-Infective Agents; D001618:beta-Lactamases