Diagnostic rule may flag UTIs without culturing. (Also Avoids Unneeded Antibiotics).

HALIFAX, N.S. -- A simple diagnostic rule for managing uncomplicated urinary tract infections in women shows promise as a way to cut unnecessary antibiotic use and the volume of urine cultures.

The rule focuses on testing for pyuria, the presence of dysuria, and the intensity of discomfort. This strategy allows for telephone-based triage and prescribing when appropriate, minimizes the use of urine cultures, and reduces unnecessary antibiotic use that may select resistant strains of uropathogens, Dr. Warren J. McIsaac said at the annual meeting of the North American Primary Care Research Group.

The rule's effectiveness must be validated in an independent patient population before it is routinely used, said Dr. McIsaac of the University of Toronto.

The rule was devised by analyzing clinical features and outcomes of 231 patients at any of four family medicine clinics affiliated with the university The patients were at least 16 years old and had symptoms that suggested a possible urinary tract infection (UTI). Most of the patients had urinary frequency and dysuria. The inclusion criteria were kept relatively broad to enroll a group that reflected usual practice, Dr. McIsaac said.

A urine specimen was collected from each patient and cultured. A UTI was confirmed if the specimen contained more than 100,000 colony-forming fecal pathogens per milliliter or at least 100 coliform pathogens per milliliter.

The participating physicians made a clinical diagnosis of UTI in 204 patients and prescribed antibiotic therapy for 186 (81% of the total group). But a UTI was confirmed by culturing in only 123 patients (53%). Thus, about one-third of the antibiotic prescriptions were unnecessary--a rate similar to rates seen in prior studies.

Further analysis identified four clinical features that independently identified patients with a ...