Nonenteric Escherichia coli isolates from dogs: 674 cases (1990-1998)

Objective-To determine nonenteric sites associated with Escherichia coli is olates in dogs and the antimicrobial susceptibilities of the isolates. Design-Retrospective study. Sample Population-17,000 canine specimens. Procedure-Medical records of 17,000 canine specimens submitted for bacterio logic culture were examined and the number of isolations of E coli was dete rmined. For these cases, records were further examined with respect to body system involvement, sex, concurrent infection with other species of bacter ia, and antimicrobial susceptibility. Results-674 E coli isolates (424 from urine, 62 from the skin, 52 from the respiratory tract, 45 from the ear, 43 from the female reproductive tract, 25 from the male reproductive tract, and 23 from other organ systems) were identified. There was a significantly higher proportion of isolates from ur ine specimens from spayed females than from sexually intact females or male s. Escherichia coli was isolated in pure culture from 65.9% of the specimen s. Most E coli isolates were susceptible to norfloxacin (90%), enrofloxacin (87.5%), gentamicin (90.7%), and amikacin (85.9%). Conclusions and Clinical Relevance-Most nonenteric E coli infections in dog s involve the urinary tract. Amikacin, gentamicin, norfloxacin, and enroflo xacin have the highest efficacy against canine E coli isolates. For E coli isolates from dogs, in vitro susceptibility to commonly used antimicrobial agents has remained fairly stable during the past decade.