Gerardo Bautista Trujillo - Department of Microbiology, Faculty of Veterinary Medicine and Zootechnics, Autonomous University of Chiapas, Chiapas, Mexico
Mayra Hernández-Hernández - Faculty of Agronomic Sciences, Autonomous University of Chiapas, Chiapas, Mexico‎
Javier Gutiérrez-Jiménez - Institute of Biological Sciences, University of Sciences and Arts of Chiapas, Chiapas, Mexico‎
Fernando Azpiri-Álvarez - Faculty of Veterinary Medicine and Zootechnics, Autonomous University of Chiapas, Chiapas, Mexico
Rene Pinto Ruiz - Faculty of Agronomic Sciences, Autonomous University of Chiapas, Chiapas, Mexico‎
Francisco Guevara-Hernández - Faculty of Agronomic Sciences, Autonomous University of Chiapas, Chiapas, Mexico‎
Benigno Ruiz Sesma - Faculty of Veterinary Medicine and Zootechnics, Autonomous University of Chiapas, Chiapas, Mexico
Paula Mendoza-Nazar - Faculty of Veterinary Medicine and Zootechnics, Autonomous University of Chiapas, Chiapas, Mexico
Daniel González-Mendoza - Institute of Agricultural Sciences, Autonomous University of Baja California, Baja California, Mexico

Piglets suffer from diarrhea caused by the Shiga toxin-producing Escherichia coli (STEC) and can be carriers of the bacteria, with public health consequences in developing countries. The aim of the present study was to study the prevalence of STEC O۱۵۷ in feces of ۴۶۵ piglets and ۵۴ food mixes from backyard systems, the antimicrobial susceptibility of STEC and the frequency of genes encoding extended-spectrum β-lactamases. The E. coli was isolated from ۷۵.۹۰ % of the evaluated feces. The STEC strains were identified in ۳۳.۱۱% of the sampled population and in ۴۳.۶۰% of the piglets carrying E. coli. Among STEC strains, the stx۱ gene was the most frequent (۲۲.۳۰%). The rfbO۱۵۷ gene was amplified in ۴۷.۴۰% of the STEC strains. High frequencies of STEC strains were not susceptible to ampicillin, carbenicillin and tetracycline. The blaTEM gene (۵۲) was the most frequent among strains not susceptible to ampicillin. Class ۱ integrons were the most frequent in those strains. Of the identified STEC strains, ۴۸.۷۰% were considered as multi-drug resistant and ۱.۹۰% were considered extensively drug resistant. In the supplied food, STEC O۱۵۷ strains were identified in ۲۵.۰۰% of the STEC strains. We conclude that the piglets from backyard systems are carriers of STEC O۱۵۷ strains not susceptible to common antibiotics, including penicillins and tetracyclines. In addition, supplied food is a source of this type of pathogenic bacteria. Through their direct contact with humans, the piglets and food represent a potential source of bacterial dissemination capable of producing gastrointestinal infections in humans.

Antimicrobial susceptibility, ‎ Carrier, ‎ Diarreagenic Escherichia coli, ‎ Prevalence, Zoonosis