Outcome following antimicrobial therapy for asymptomatic bacteriuria in elderly women resident in an institution.

Twenty-six elderly (mean age 83.3 +/- 8.7 years) institutionalized women with asymptomatic bacteriuria were treated with antibiotic therapy, including initial single-dose and subsequent 2 weeks' therapy, then 6 weeks' therapy if relapse occurred. Forty-seven courses of single-dose, 30 of 2 weeks', and 10 of 6 weeks' therapy were given during a 1-year period. At 8 weeks of follow-up, 57% of single-dose courses, 52% of 2-week, and 29% of 6-week had been followed by relapse, and 32%, 24%, and 29%, respectively, by reinfection. Outcome with single-dose therapy did not correlate with infecting organism, antimicrobial therapy, or presence of pyuria with the infection. However, residents who persistently relapsed following single-dose therapy appeared to be a less-well population, as evidenced by a significantly greater age, number of chronic disease diagnoses and medications, as compared to those who were cured by single-dose therapy. Thus, recurrent infection, including both relapse and reinfection is the usual short-term outcome following therapy for asymptomatic bacteriuria in this population. Differences in patient characteristics may prove useful in predicting which individuals may respond to minimal therapy.