Multidrug Resistance of Escherichia coli Strains Isolated From Bovine Feces and Carcasses in Northeast Mexico
Ana Verónica Martínez-Vázquez, José Vázquez, Luis Mario Leyva-Zapata, Hugo Barrios-García, Gildardo Rivera, Virgilio Bocanegra‐García
Abstract
In this work, the antimicrobial resistance profile of Escherichia coli strains ( n = 248) isolated from bovine feces and carcass samples from Tamaulipas, Mexico, was evaluated. Susceptibility to 12 antibiotics conventionally used in human and veterinary treatments was determined according to Clinical and Laboratory Standards Institute guidelines. Genes encoding resistance to tetracycline ( tetA and tetB ), streptomycin ( str A), aminoglycoside ( aad A), and β-lactamase ( bla TEM and bla SHV ) were investigated by PCR. Also, stx 1, stx 2, eae, bfp , and hly A encoding virulence factors were determined. Of the isolates, 85.9% were confirmed as E. coli strains. Among the 213 E. coli isolates tested, 94.8% (202/213) showed resistance for at least one antimicrobial, mainly ampicillin (83.0%; 177/213), cephalothin (76.0%; 162/213), and tetracyclines (69.0%; 147/213). In all the other antibiotics tested, the resistance percentage was below 36%. A multidrug-resistant phenotype was found in 72.7% of the tested strains. The presence of the tet gene ( tet A or tet B) was detected in 43.1% of the isolates, the str A gene in 17.3%, and aad A1 in 51.6%. The bla TEM and bla SHV genes were found in 10.3 and 0.4% of the isolates, respectively. stx 1 was detected in 4.2% of isolates, stx 2 in 7.0, and hly A in 2.8%. The virulence genes, eae and bfp , were not detected in any strain. These results indicate that Tamaulipas food products of bovine origin can be a source of multiresistant E. coli strains for the environment and exposure for consumers.