Experimental Candida albicans, Staphylococcus aureus, and Streptococcus faecalis pyelonephritis in diabetic rats

Pyelonephritis was studied after an intravenous injection of Candida albicans, Staphylococcus aureus, or enterococcus in alloxan-diabetic rats and in water-diuresing or non-diuresing nondiabetic rats. The renal microbial populations of C. albicans or S. aureus were found to be greater than 10(5) colony-forming units per g for up to 42 days in diabetic rats, whereas the kidneys tended to become sterile in nondiabetic rats. No significant difference was found in the course of enterococcal pyelonephritis in diabetic versus control rats. The difference in the 50% infective dose for each microorganism between diabetic and control rats was less than or equal to log10. Neither duration of diabetes nor weight loss contributed to the greater and more sustained renal populations of C. albicans and S. aureus in diabetic rats. The inflammatory reaction in kidneys infected with S. aureus or C. albicans was greater in diabetic rats. Fungus balls associated with ureteral obstruction and gross multiple renal abscesses occurred in diabetic, but not in nondiabetic, rats infected with Candida. Growth of C. albicans and S. aureus in vitro in urine from diabetic rats was significantly greater than it was in urine from control rats. Addition of water or glucose to the urine of non-diuresing, nondiabetic rats significantly increased in vitro growth of S. aureus and C. albicans. These studies demonstrate greater severity of infection in the diabetic kidney due to S. aureus and C. albicans, which can be partially explained by decreased inhibitory activity of urine for these organisms in diabetic rats.