Microbiological outcomes in women with diabetes and untreated asymptomatic bacteriuria

Background: Asymptomatic bacteriuria is common in diabetic women. Treatment of asymptomatic bacteriuria is not beneficial, but the natural history of the microbiology of asymptomatic bacteriuria has not been well described. Objective: To describe the microbiological outcomes of bacteriuria in diabetic women with untreated asymptomatic bacteriuria. Methods: Study subjects were initially identified through ambulatory endocrinology clinics. They were enrolled if they had two positive urine cultures ≥10⁸ cfu/l with the same organism within 2 weeks and no symptoms referable to urinary tract infection. Women initially received a 2-week course of placebo with follow-up cultures obtained at the end of treatment and 4 weeks post-treatment. Subsequently, the prevalence of bacteriuria was determined with urine cultures obtained every 3 months to a maximum of 36 months. Outcomes at yearly intervals were designated as one of: persistent bacteriuria; spontaneous resolution; resolution with antibiotics for symptomatic urinary infection; or resolution with antibiotics given for other indications. Women with and without persistent or frequent bacteriuria were compared to identify variables associated with bacteriuria. Results: The prevalence of bacteriuria in the study cohort declined to about 50% by 9 months, and subsequently remained stable throughout 3 years follow-up. Almost 20% of subjects remained bacteriuric with the original infecting organism throughout the period of observation. With evaluation at 12-month intervals, approximately one-quarter of subjects had each of the four potential outcomes of: resolution following antibiotic therapy for symptomatic urinary infection, following antibiotic therapy for other indications, spontaneous resolution without antibiotics, and persistent bacteriuria with the same organism. Women infected with gram-negative organisms were more likely to have persistent bacteriuria. Many women with resolution of initial bacteriuria, with or without antibiotics, became bacteriuric again during follow-up. Conclusions: Women with asymptomatic bacteriuria and diabetes tend to have persistent or recurrent asymptomatic bacteriuria. Bacteriuria is benign, and seldom permanently eradicable.