Diagnosis of Coliform Infection in Acutely Dysuric Women

Abstract

We reevaluated conventional criteria for diagnosing coliform infection of the lower urinary tract in symptomatic women by obtaining cultures of the urethra, vagina, midstream urine, and bladder urine. The traditional diagnostic criterion, ≥10⁵ bacteria per milliliter of midstream urine, identified only 51 per cent of women whose bladder urine contained coliforms. We found the best diagnostic criterion to be ≥10² bacteria per milliliter (sensitivity, 0.95; specificity, 0.85). Although isolation of 5 coliforms per milliliter of midstream urine has had a low predictive value in previous studies of asymptomatic women, the predictive value of the criterion of ≥10² per milliliter was high (0.88) among symptomatic women in whom the prevalence of coliform infection exceeded 50 per cent. In view of these findings, clinicians and microbiologists should alter their approach to the diagnosis and treatment of women with acute symptomatic coliform infection of the lower urinary tract. (N Engl J Med. 1982; 307:463–8.)