Staphylococcus saprophyticus: a frequent cause of acute urinary tract infection among female outpatients.

The frequency of Staphylococcus saprophyticus, formerly Micrococcus subgroup 3, as the cause of bacteriuria is reported. Of 787 consecutive female outpatients with signs of bacteriuria, 173 (22.0%) yielded S. saprophyticus, predominantly in pure culture and in high counts. In the age group 16--25 years, this organism was demonstrated in no less than 42.3%. In hospitalized women and in men with signs of bacteriuria, on the other hand, S. saprophyticus was a rare finding (0.9% and 0.5%, respectively). The figures in female outpatients aged 15--30 years were similar over a three-year period, but higher during summer and fall as compared with those in winter and spring. The patients regularly had rather severe symptoms of acute urinary tract infections with dysuria and often loid pain. Hematuria and pyuria were common. All strains of S. saprophyticus had a fairly even and high susceptibility to antimicrobial agents except nalidixic acid. Recurrent infections were common. The origin of this infection is still obscure.