Uterine bacterial flora and uterine lesions in bitches with cystic endometrial hyperplasia (pyometra).

Thirty-eight complete genital tracts were obtained fresh from local veterinary practices after bitches had been ovariohysterectomised for the treatment of cystic endometrial hyperplasia (pyometra). The aerobic and anaerobic culture of swabs obtained aseptically from the uterine lumen demonstrated the presence of Escherichia coli in 28 of the 29 cases from which bacteria were isolated and, from 25, a pure culture was obtained. Sixteen different serotypes were identified from 24 genital tracts; 032K+ CNF+ was isolated from four of 16 cases and 04K-; from three of 16 cases. Cytotoxin necrotising factors (CNFs) were identified in seven of the 16 serotypes; they included 02, 04, 06, 022, 025, 045 and 075, which except for 06 and 045 were haemolytic. Strains 04K- and 07K+ completely destroyed the integrity of the endometrial epithelium whereas 088K+ and 088K- had the least effect. The scores for the reduction in the integrity of the endometrial epithelium and the degree of infiltration of inflammatory cells were greater in the presence of CNF 1.