Recent advances have led to a renewed interest in urinary tract infections in females. First, current research has reassessed the previously used definition of infection as a positive culture with ≥ 100,000 colonies per ml. Norden and Kass1 originally defined a positive culture as ≥ 105 colonies per ml because they found a 96% predictability of a third positive culture if the 2 previous cultures were positive. However, their studies primarily involved pregnant women who were asymptomatic at the time of culture and were not known to be at high risk for recurrent disease. Other authors2,3 reported that symptomatic disease is often associated with colony counts of less than 105 colonies per ml. These studies have thus led to reconsideration of the best way to define infection microbiologically. The roles of new pathogens such as Chlamydia trachomatis, herpes simplex virus (HSV), and Staphylococcus saprophytics have also been demonstrated in recent studies.