Automated bacteriuria screening using the Berthold LB 950 luminescence analyser

Abstract

The Berthold LB950 Automatic Luminescence Analyser was used to estimate bacterial adenosine triphosphate in urine. The system provided a rapid (15 min) and fully automated screening test for bacteriuria at the 10(5) CFU/ml level. Bioluminescence results for 1040 urines were compared with viable counts using two reference culture methods and frequency distributions of bacterial counts and adenosine triphosphate levels were calculated. With a specificity of 79% the automated method showed a sensitivity of 84% using a pour plate reference count and 91% using a standard loop reference count. When contaminated urines were excluded the sensitivity improved to 98%. The automated bioluminescence test, though expensive, was shown to work well with good quality specimens.

Modified Methylene Blue Screening Method for Significant Bacteriuria

“…Among the numerous urine samples that are investigated by hospital laboratories daily, only a small portion of about 25-30% are actually infected and require culture [1,2]. However, a reasonable amount of hospital resources, laboratory staff time and efforts are expended on the conventional method of diagnosing urinary tract infection which involves the quantitative or semi-quantitative culture of urine specimens on appropriate solid medium and reading the culture results after overnight incubation.…”