Prevalence of Escherichia coli O157:H7 isolated from fecal samples of diarrheic camels in Tunisia

Abstract

Shiga‑toxin‑producing E. coli (STEC) is a foodborne pathogen associated with outbreaks worldwide that can be identified in the feces and in the meat of food‑producing animals. Our study aimed to evaluate the incidence of E. coli O157:H7 in the feces of diarrheic camels (Camelus dromedarius) in Tunisia. From January 2018 to April 2019, 120 unduplicated fecal samples were obtained from diarrheic camels located in southern Tunisia. Non‑sorbitol‑fermenting colonies were confirmed as E. coli O157 via latex agglutination test and were screened for the presence of rfbEO157, fliCH7, stx1, stx2, eaeA, and ehxA genes by PCR. All isolates were examined for their susceptibility to 21 antibiotics. Of the 70 E. coli isolates that were recovered from 120 diarrheic camels, 4 (5.7%) were identified as STEC O157:H7. All isolates harbored ehxA and eae genes. Shiga toxin genes stx2 and stx1 were present in 50% and 25% of isolates, respectively. All E. coli O157:H7 isolates were sensitive to amoxicillin/clavulanic acid, cefotaxime, cefepime, aztreonam, colistin, and sulfamethoxazole‑trimethoprim. All isolates belonged to the phylogroup E. This is the first report of E. coli O157:H7 isolates from diarrheic camels in Tunisia with a prevalence of 4 isolates (3.3%) amongst 120 fecal samples. This study supports the necessity for a platform purposed for regular screening and surveillance programs in food‑producing animals and meat products, to perform early and rapid identification of food‑borne pathogens.

Keywords

• E. coli O157:H7
• Camels
• Shiga‑like toxin genes
• Enterohemorrhagic Escherichia coli
• Enterohaemolysin (ehxA)
• Antimicrobial resistance