Detección y caracterización fenotípica y molecular de aislados de Escherichia coli O157:H7 de origen canino (Canis lupus familiaris)

Abstract

Escherichia coli (E. coli) O157: H7 is one of several Shiga toxin-producing serotypes that cause disease in both humans and animals, the organism likely evolved through horizontal acquisition of genes for Shiga toxins and other virulence factors . The objective was to detect and characterize phenotypically and molecularly isolates of E. coli O157: H7 of canine origin (Canis lupus familairis), starting from a bank of E. coli strains (n = 122) for the detection of serotype O157: H7 obtaining 4 positive samples, the virulence genes found in the total of the samples were eaeA 5.74% and hlyA 0.82% in the first instance, for the case of stx1 and stx2 no positive results were obtained. The investigation was deepened with the transconjugation of donor and receptor bacteria (Strain J53) by means of cultures, once the colonies were obtained, the transconjugates were carried out with each positive bacterium for E.coli O157: H7 and their respective transconjugates (n = 9); Virulence genes were evaluated in the case of eaeA 88.88%, hlyA 44.44%, and resistance genes such as: TetA 22.22%, blaTEM 77.77%, blaCTX-M 88.88% by means of the PCR technique. For the detection of the resistance profiles of extended spectrum beta-lactamases (ESBL) and AmpC-type beta-lactamases, the "Kirby & Bauer" disk diffusion method was performed, showing the 8 bacterial strains to be positive for both ESBL and AmpC; in addition to finding phenotypic resistance for: Cefotaxime 55%, Ciprofloxacin 33%, Enrofloxacin, 44%, Sulfamethoxazole / Trimetropim 44%, Ampicillin, Vancomycin and Erythromycin 88%. This study provides information about the prevalence of antimicrobial resistance in dogs from the center of the country.