[Bacteria and leukocyte count in the urine in the diagnosis of urinary tract infections].

The count of bacteria in fresh, unstained, uncentrifuged urine specimens, using a phase-contrast microscope, magnification X400, and a hemocytometer chamber, is a simple method to exclude urinary tract infection. The specificity of this method is 94%, while the sensibility is 66%. We exclude an urinary infection when the count is less than 5 bacteria/0.1 ml. If we add to bacteria the evaluation of pyuria, the sensibility of this method does not change. On the contrary what we observe is an increase of the false positives. Bacteria more easily identified in urine specimens are E. Coli and Klebsiellae; the bacterioscopy has confirmed respectively 82% and 100% of positive urinecultures. The corresponding values for Protei and Streptococci are 23% and 20% respectively. This method is very simple also for teaching; it requires only a few minutes and is inexpensive. Its most useful utilization is the exclusion of urinary tract infection when the concentration of bacteria in the urine is less than 5 bacteria/0.1 ml.