Biochemical phenotypes of Escherichia coli in dogs: comparison of isolates isolated from bitches suffering from pyometra and urinary tract infection with isolates from faeces of healthy dogs.

Escherichia coli from dogs suffering from pyometra and/or urinary tract infection (UTI) were compared with faecal E. coli. We studied 79 isolates from pyometra, 96 from UTI, 91 from faeces of healthy dogs and 60 from faeces of bitches with pyometra. The isolates included 16 bitches with pyometra where E. coli were isolated from both the uterus and the urinary tracts. All isolates were typed with the aid of an automated typing system for biochemical fingerprinting (the PhP-EC system). The PhP types of uterine E. coli isolates from bitches with pyometra showed higher homogeneity, calculated as the mean of similarity between isolates (rmean = 0.79) than epidemiologically unrelated isolates, such as those isolated from faeces (rmean = 0.69) or UTI (rmean = 0.70). This finding suggests that many of the pyometra isolates derives from related clones. Mucoid and nonmucoid uterine isolates from the same sample were generally of the same PhP type. In all 10 cases uterine E. coli isolates were identical or very similar to isolates from faeces of the same bitch. Furthermore, E. coli isolates from both UTI and the infected uterus in the same bitch were identical or very similar in 88% of the cases. It was concluded that E. coli associated with canine pyometra derive from the faecal flora and that the urinary tract is infected by the same E. coli clone as the uterus of a bitch with pyometra.