Urinary tract infections caused by Staphylococcus saprophyticus. A matched case control study.

Epidemiological and clinical aspects of 270 episodes of urinary tract infection caused by Staphylococcus saprophyticus were studied. The cases were randomly selected and matched consecutively with 276 others of urinary tract infection according to sex, age and temporal occurrence. Such infections were found typically among young women in the outpatient health service. They were common among professionals handling meat products and were especially associated with prior outdoor swimming. Common symptoms of inflammation of the lower urinary tract, haematuria and pyuria were seen more often among patients with S. saprophyticus infections. Some cases of asymptomatic S. saprophyticus infection, however, were seen. We found S. saprophyticus as the cause of 13% upper urinary tract infections, an incidence which is higher than has been reported for other bacteria. Staphylococcus saprophyticus was less correlated to nephrolithiasis and was not a common cause of catheter-induced infections.