Prevalence, virulence genes, and antimicrobial profiles of Escherichia coli O157:H7 isolated from healthy cattle in Tunisia

  • Ghassan Tayh Service de Microbiologie et d’Immunologie, Ecole Nationale de Médecine Vétérinaire, Univ. Manouba, Sidi Thabet, Tunisia https://orcid.org/0000-0002-7180-6787
  • Salma Mariem Boubaker Service de Microbiologie et d’Immunologie, Ecole Nationale de Médecine Vétérinaire, Univ. Manouba, Sidi Thabet, Tunisia
  • Rym Ben Khedher Service de Microbiologie et d’Immunologie, Ecole Nationale de Médecine Vétérinaire, Univ. Manouba, Sidi Thabet, Tunisia
  • Mounir Jbeli Ministère de la Défense Nationale, Direction Générale de la Santé Militaire, Service Vétérinaire, Tunis, Tunisia
  • Faten Ben Chehida Service de Microbiologie et d’Immunologie, Ecole Nationale de Médecine Vétérinaire, Univ. Manouba, Sidi Thabet, Tunisia
  • Aymen Mamlouk Service de Microbiologie et d’Immunologie, Ecole Nationale de Médecine Vétérinaire, Univ. Manouba, Sidi Thabet, Tunisia
  • Monia Dâaloul-Jedidi Service de Microbiologie et d’Immunologie, Ecole Nationale de Médecine Vétérinaire, Univ. Manouba, Sidi Thabet, Tunisia
  • Lilia Messadi Service de Microbiologie et d’Immunologie, Ecole Nationale de Médecine Vétérinaire, Univ. Manouba, Sidi Thabet, Tunisia
Keywords: Escherichia coli, O157:H7, healthy cattle, antimicrobial susceptibility, virulence factors, Shiga toxins, Tunisia

Abstract

Introduction: Shiga toxin-producing Escherichia coli (STEC) O157:H7 is associated with intestinal infection in humans and is considered an important cause of food-borne diseases. The aim of the study was to assess the incidence of E. coli O157:H7 in fecal samples of healthy cattle collected in slaughterhouses (n = 160) and from five farms (n = 100).

Methodology: E. coli isolates were detected on MacConkey agar. A total of 236 E. coli isolates were recovered from fecal samples of healthy cattle. We used sorbitol MacConkey medium to detect non-sorbitol fermenting colonies. These bacteria were examined for the presence of O157:H7 antigen by latex agglutination. The isolation of E. coli O157:H7 has been confirmed with PCR amplification of rfbEO157 and fliCH7 specific genes for serogroup O157 and with multiplex PCR of stx1, stx2, eaeA, and ehxA. All isolates were examined for their susceptibility to 21 antibiotics by the disc diffusion method.

Results: Of the 236 E. coli isolates, 4.2% (10/236) were positive for STEC O157:H7. Shiga toxin gene (stx2) and ehxA were present in 70% of isolates, stx1 and eae were confirmed in 60% of the isolates. Other virulence factors screened (fimH, sfa/focDE, cdt3, traT, iutA, and hlyA) were present among the 10 isolates. All E. coli O157:H7 isolates were sensitive to amoxicillin/clavulanic acid, cefotaxime, cefepime, aztreonam, colistin, and sulfamethoxazole/trimethoprim. All isolates belong to the phylo-group E.

Conclusions: This is the first study of the incidence of E. coli O157:H7 in cattle in Tunisia. Our finding proves the existence of STEC O157:H7 in healthy animals producing food for human consumption which could be a source of food-borne disease.

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Published
2022-08-30
How to Cite
1.
Tayh G, Boubaker SM, Ben KhedherR, Jbeli M, Ben ChehidaF, Mamlouk A, Dâaloul-JedidiM, Messadi L (2022) Prevalence, virulence genes, and antimicrobial profiles of Escherichia coli O157:H7 isolated from healthy cattle in Tunisia. J Infect Dev Ctries 16:1308-1316. doi: 10.3855/jidc.15855
Section
Original Articles