Evaluation of a rapid bacteriuria screening instrument

A newly modified, semiautomated instrument (Bacteriuria detection device (BDD) designed to detect the presence of bacteriuria in less than 3 min was compared to quantitative urine culture plating techniques. The instrument consists of a self-enclosed vacuum—filtration—staining system in which a 1-ml urine filtrate is stained on a filter. The resulting color determines the quantitation. Of the total of 525 clinical urine specimens tested, 66 (12.6%) were uninterpretable due to pigment deposition or inability to complete the filtering process (clogging of the filter). Of the remaining 459 specimens, 93 (20.3%) had a plate quantitation colony count of 10⁵ colony-forming units (CFU)/ml or more. The BDD detected 94.2% of these positive specimens if only significant pathogens were included (85% if specimens that were probably contaminated were also included). For specimens containing significant pathogens at 10⁴–10⁵ CFU/ml, the BDD detection rate was 41%. The device detected most (94.3%) gram-negative bacilli and enterococci at colony counts of 10⁵ CFU/ml or more. In addition, the BDD accurately detected 95.6% of specimens with no growth or fewer than 10⁴ CFU/ml. With several proposed modifications, these results suggest that this instrument is potentially useful as a urine screening device in a select population.