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

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. 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. 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). 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%). 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.