Detection of virulence and antimicrobial resistance genes in Escherichia coli isolates from diarrhoiec dogs in Iran

Abstract

This study was conducted to investigate the presence of some virulence and antimicrobial resistance genes in E. coli isolates from diarrhoiec dogs in Iran. Seventy dogs were randomly selected by direct sampling. Rectal swabs were collected and cultured for isolation and identification of E. coli following standard methods. Polymerase chain reaction (PCR) was used to detect 5 virulence genes and 12 antibacterial resistance genes in 14 of the isolates. From the 70 rectal swabs cultured, 33 (47.1%) gave positive growth of E. coli. Out of 14 isolates tested for the presence of virulence genes, 9 (64.3%) were positive for PCR of stx (1), 5 (35.7%) were positive for stx (2), 7 (50%) were positive for eae, and 1 (7.1%) isolate was positive for cnf (1). Out of the 14 isolates tested for the presence of antibacterial resistance genes, 9 (64.3%) were positive for CITM gene, 6 (42.9%) were positive for aad (A1) and bla (SHV), 5 (35.7%) were positive for tet (A), dfr (A1) and cat (1), 4 (28.6%) were positive for aac (3)-IV, 3 (21.4%) were positive for both tet (B), sul (1) and cml (A), while 1 (7.1%) of the isolate was positive for ere. The results showed that enterohaemorrhagic E. coli (EHEC), shiga toxigenic E. coli (STEC) and necrotoxic E. coli (NTEC) strains harboring several antibacterial resistance genes could be involved in canine diarrhoea in Iran.