Serological identification of Escherichia coli isolated from cats and dogs.

In a group of 112 cats, examined during an outbreak of diarrhea, 104 (92.8%) yielded Escherichia coli with identifiable O groups as compared to 12 (21.8%) of 55 control cats apparently free of intestinal ailments. E. coli group O6 occurred in 49.1% of the cats with diarrhea, and persisted in this group of cats at about the same rate when examined for a period of ten months. E. coli group O6 was not isolated from the control group. Specimens were also collected from dogs with various clinical signs. E. coli O4 and O6 strains appear to be important potential pathogens for canine species and were found to spread from one dog to another when in close contact. E. coli group O4 was identified in ten and O6 in three of 14 dogs examined. All isolates in which the O group could be identified were hemolytic.