Diagnosis of urinary tract infection. The interpretation of colony counts.

The results of 787 consecutive suprapubic specimens in children were studied. Ninety-two patients with 128 positive cultures were reviewed. Sixty-five children had documented urinary tract infection (UTI) proven by other cultures. Of these, 55 per cent had colony counts less than the traditional 100,000 colony forming units/ml., and 9 per cent had colony counts less than 10,000. Organisms usually regarded as "contaminants" (Staphylococcus epidermidis, mixed organisms) were occasionally proven to cause UTI.