Rapid identification of Escherichia coli in monomicrobial urine specimens by a fluorogenic assay

Abstract For rapid identification of Escherichia coli in routine diagnosis of urinary tract specimens we applied the 4-methylumbelliferyl- β - D -glucuronide-(MUG)-fluorescence method. Urinary tract specimens were inoculated directly on Fluorocult-brolacin-(CLED)-agar and examined for blue fluorescence and positive indole reaction 20 h later. Enterobacteriaceae were identified by commercially available identification systems. A total of 4851 urinary tract specimens revealing 466 isolates as monomicrobic cultures of E. coli were investigated. Sensitivity of identification of E. coli by Fluorocult-brolacin-agar proved to be 70.8%, specificity 95.7%, positive predictive value 98.2%, negative predictive value 49.8%, and efficiency 76.6%. Our results demonstrate that the useof commercially available identification systems could be restricted to nonfluorescent colonies to save time and costs.