[Quantitative determination of urine bacteria in the diagnosis of urinary tract infections in children].

Bacteria counts in fresh, unstained, uncentrifuged urine specimens, using a phase-contrast microscope, magnification X 400, and a hemocytometer chamber, proved to be a very useful method not only of excluding (specificity 0.92) but also identifying urinary tract infection (sensitivity 0.90) in children. The presence of greater than 5/0.1 ml bacteria in the urine was taken as the threshold value. The evaluation of leukocyturia alone did not alter the sensitivity of the method, even when it was associated with bacteriuria. When Proteus was isolated from urine cultures, the bacteria count proved negative in 60% of cases; otherwise when different bacteria were isolated in urine cultures, they were then identified during the bacteria count. The method is simple, inexpensive and rapid (it requires only a few minutes) and it may be used in a pediatric outpatient or hospital setting.