Detection of bacteriuria: manual screening test and early examination of agar plates

We assessed two procedures for the initial processing of urine specimens: (i) manual screening of urine samples by inoculation into tryptic soy broth and incubation for 3 to 6 h, and (ii) examination of agar plates inoculated with urine and incubated for 4 to 6 h. Of the urine samples with greater than 10(5) colony-forming units per ml, 73.6 and 90.1% were detected with the broth cultures after 3 and 6 h of incubation, respectively. The organisms not detected at 6 h were Corynebacterium spp., Lactobacillus spp., and one of six isolates of yeasts. When inoculated plates were examined for growth, 53.3 and 80.0% of the specimens with greater than 10(5) colony-forming units per ml were detected after 4 and 6 h of incubation, respectively. Of the cultures with significant growth of Enterobacteriaceae or Pseudomonas spp., 95% were detected on the plates after 6 h of incubation.