Predictive value of antimicrobial susceptibility from previous urinary tract infection in the treatment of re-infection.

Recurrent urinary tract infections are often re-infections; therefore, antimicrobial susceptibility test results from a previous episode may guide the empiric therapy in subsequent episodes. This analysis provides predictive values of the antimicrobial susceptibility of previous Escherichia coli isolates for the treatment of re-infections in routine clinical practice. If resistance to ampicillin, trimethoprim, or ciprofloxacin is detected, re-prescription within 3 months is imprudent. Susceptibility to nitrofurantoin, ciprofloxacin, or trimethoprim in a previous sample supports their prescription for a re-infection within 3 months and up to a year. Resistance to nitrofurantoin is low and, once detected, decays relatively quickly. Nitrofurantoin should be considered as a first-line agent for initial and repeat treatment.