Detection of enterotoxin and adhesin genes of Escherichia coli strains isolated from feces of healthy dogs

This study aimed to investigate the presence of genes encoding the enterotoxins STa and Stx1 and the adhesins K99 and Intimin in E. coli strains isolated from feces of dogs who appeared to be healthy. Rectal swab samples were collected from 50 dogs who visited the Veterinary Hospital of the University of Brasilia and 48 E. coli isolates were obtained. No positive isolates were found for STa and K99. However, positive results were found in 21 isolates (43.7%) for Stx1 and 14 isolates (29%) for the Intimin gene (eae). The antimicrobial sensitivity profile was also assessed for the following antibiotics: sulfazothrim, azithromycin, enrofloxacin, ceftiofur, amoxicillin + clavulanate, doxycycline, ampicillin, and cephalexin. The antibiotics on which the isolates showed the highest resistance were ampicillin (25%), doxycycline (22.9%) and cephalexin (20.8%). As for sensitivity, the isolates were most sensitive to sulfazothrim (87.5%), azithromycin (85.41%) and enrofloxacin (77%). Healthy dogs can carry multidrug-resistant E. coli strains that can also carry enterotoxin and adhesin genes, thus indicating that, the proximity between dogs and humans may contribute to possible zoonotic transmission of these microorganisms.