Occurrence and Molecular Characterization of Shiga Toxin-Producing Escherichia coli Isolates Recovered from Cattle and Goat Meat Obtained from Retail Meat Shops in Rawalpindi and Islamabad, Pakistan

Shiga toxin-producing E. coli (S FEC) also known as Verocytotoxin producing E. coli (VTEC) have emerged as important food-borne pathogens of zoonotic importance causing outbreaks and sporadic cases of diarrhoea, haemorrhagic colitis and haemolytic uraemic syndrome. The objective of the study was to understand the distribution of various S FEC in raw meat of cattle and goats collected from different meat shops of Rawalpindi and Islamabad. Raw meat samples (n=101) were analysed for presence of four virulence genes (stx1, stx2, eae and ehxA). The samples positive for one or more virulence genes were subjected to isolation using sorbitol MacConkey agar (SMAC). Of 101 samples 44 (43.5%) were found positive for one or more virulence genes. The most common combination of virulence genes in samples was stx1, stx2, ehxA (9/44; 20.4%). Nine E. coli isolates positive for one or more virulence genes were recovered from 44 positive samples. The analysis of E. coli isolates for serogroups O157, O26, O103, O111 and O145 using PCR indicated that three E. coli isolates were O111 and one was O26. The serogroup of five E. coli isolates could not be identified. Antibiotic susceptibility profiles of the E. coli isolates using the disc diffusion method indicated antimicrobial resistance ranging from 33.3 to 100% against eight antibiotics of seven different classes. Isolation of antimicrobial resistant STEC of zoonotic significance from meat samples indicated that meat sold in the shops of Islamabad and Rawalpindi may be the source of transmission of AMR STEC to humans. (C) 2020 PVJ. All rights reserved