Genetic Diversity of Multidrug-Resistant CMY-Producing Escherichia coli from Feces and Soil in a Small-Scale Pig Farm.

Diarrheagenic Escherichia coli cause diarrheal diseases, which are a public health concern and affect mainly developing countries. Multidrug-resistant (MDR) pathogens have been spreading in different sources, including animals and the environment. E. coli strains were obtained from a small-scale pig farm and 33 antimicrobials were tested. All strains were classified as MDR and harbored several antimicrobial resistance genes (ARGs) [blaCMY, blaOXA-1-like, blaSHV, tet(A), tet(B), aadA, aac(6')-Ib, aph(3')-Ia, sul1, sul2, sul3, floR, and cmlA] and plasmids. Besides, mutations in quinolone resistance-determining region of GyrA (Ser83Leu and Asp87Asn) and ParC (Glu84Asp) were detected. Among the MDR E. coli, nine strains (52%) presented diarrheagenic virulence genes, including genes related to Shiga toxin-producing E. coli (STEC), enteroinvasive E. coli (EIEC), and enteroaggregative E. coli (EAEC). The pulsed-field gel electrophoresis results showed a high genetic diversity among the MDR E. coli strains. Multilocus sequence typing (MLST) analyses revealed different sequence types phylogenetically related to each other, including ST10 and ST56. Subtyping of MLST by fimH gene showed different fimH type. This study shows a high genetic diversity among MDR ARG-producing E. coli belonging to STEC, EIEC, and EAEC pathotypes obtained from a small-scale pig farm and contributes to the monitoring of antimicrobial-resistant pathogens worldwide, mainly in environmental samples, which are associated with One Health framework.