Fecal carriage of Escherichia coli harboring extended-spectrum beta-lactamase (ESBL) genes by sheep and broilers in Urmia region, Iran

Background: There is a growing concern on the impact of the presence of extended-spectrum β-lactamase (ESBL) producing Escherichia coli isolated from animals on public health. OBJECTIVES: The aim of this study was to investigate the presence of three classes of ESBL genes in E. coli isolates from sheep and broilers at a slaughter in Urmia region, Iran. METHODS: A total of 111 E. coli isolates were obtained from sheep (n=55) and broilers (n=56) fecal samples and the presence of blaCTX-M, blaTEM and blaSHV genes was detected by polymerase chain reaction (PCR). RESULTS: In general, 32 of these isolates carried blaCTX-M, 16 blaTEM, and 17 blaCTX-M plus blaTEM. None of the isolates tested was positive for the blaSHV gene. Among the 55 isolates from sheep, 33 (60%) contained one or more ESBL encoding gene; 15 (27.2%), 10 (18.2%), and 8 (14.5%) isolates were positive for blaCTX-M, blaTEM, and                                                                                                              blaCTX-M+blaTEM, respectively. Among the 56 isolates from broilers, 32 (57.1%) isolates carried at least one ESBL encoding gene; 17 (30.4%) and 6 (10.7%) isolates were positive for blaCTX-M and blaTEM genes, respectively, and the blaCTX-M+ blaTEM was identified in nine isolates (16.1%). CONCLUSIONS: This study demonstrated that sheep and broiler feces may be a reservoir of E. coli harboring ESBLs genes, with CTX-M being the predominant β-lactamase type. This may pose a public health risk, which requires future evaluation and control.