Initial management of serious urinary tract infection: epidemiologic guidelines

To obtain information necessary for the development of initial antibiotic treatment guidelines for patients with serious urinary tract infections.

Retrospective chart review.

The medical service of a 533-bed university-affiliated community hospital.

253 unselected patients hospitalized between January 1985 and December 1987 given principal discharge diagnoses of urinary tract infection, pyelonephritis, or gram-negative rod bacteremia originating in the urinary tract.

Three clinically distinct groups were identified: women under 50 years old, older women, and men. Escherichia coli was isolated from 93% of young women, 70% of older women, and 46% of men. Pseudomonas aeruginosa was isolated from 39% of men with one or more urinary tract risk factors, including recent or recurrent urinary tract infections and known genitourinary tract abnormality. The overall prevalence of Group D streptococci was only 1%. More than 20% of the patients in each group were bacteremic. In all groups, resistance to ampicillin and first-generation cephalosporins was common. Trimethoprim-sulfamethoxazole was active in 98% of young women and 85% of older women and men without urinary risk factors.

Age and gender identify clinically important subgroups of patients with serious urinary tract infections. Pending culture results, all patients should be considered bacteremic, ampicillin alone should not be prescribed, and antibiotics effective against P. aeruginosa should be given to men, especially those with risk factors.