EXAMINATION FOR HEAT-LABILE, HEAT-STABLE, AND SHIGA-LIKE TOXINS AND FOR THE EAEA GENE IN ESCHERICHIA-COLI ISOLATES OBTAINED FROM DOGS DYINGWITH DIARRHEA - 122 CASES (1992-1996)

Objective--To examine Escherichia coli isolates obtained from dogs dyi ng with diarrhea for heat-labile, heat-stable, and Shiga-like toxins a nd for the eaeA gene, which is associated with attaching and effacing lesions. Design-Retrospective study. Animals-122 dogs. Procedure-E col i isolates were tested by means of dot-blot hybridization of DNA extra cts of cultured bacteria, Medical records of dogs from which E coli is olates with virulence genes had been isolated were examined, and histo logic findings and evidence of intercurrent bacterial and viral infect ions were recorded. Results-None of the E coli isolates obtained from these dogs produced heat-labile, heat-stable, or Shiga-like toxins; ho wever, E coli isolates from 44 of 122 dogs were found to have the eaeA gene. Histologically, multifocal bacterial adherence to the epitheliu m and epithelial necrosis and detachment were seen in colonic specimen s from 20 of 44 (45%) dogs. Escherichia coli was the sole pathogen ide ntified in 15 of 44 (34%) dogs. Intercurrent pathogens, including cani ne parvovirus (n = 19), Clostridium perfringens (8), rotavirus (5), ho okworms (3), coccidia (3), and Salmonella agona (1), were identified i n the remaining 29 (66%) dogs. Clinical Implications-Attaching and eff acing E coli can be a primary or secondary pathogen in dogs with diarr hea. Antibiotic treatment is indicated in dogs with diarrhea because o f the possibility that it is primarily bacterial in origin and because , even if it is primarily viral in origin, there may be secondary bact erial infection.