• β-glucuronidase;
  • Escherichia coli;
  • identification;
  • urinary isolates

Rosco diagnostic β-glucuronidase tablets have been evaluated as a method for the identification of urinary isolates of Escherichia coli. Results were compared with those from traditional biochemical testing. A total of 539 isolates were employed, representing a variety of Gram-negative species. Reproducibility testing was also performed. After 4h incubation, 86% of E. coli isolates (both lactose-positive and lactose-negative) gave a positive reaction. Some Salmonella, many Shigella and one Citrobacter freundii isolate also gave positive reactions. All other organisms gave negative reactions. Results were highly reproducible and not influenced by choice of primary medium. The tablets are suitable for routine use in the diagnostic laboratory for the identification of lactose-positive E. coli. A suitable diagnostic table has been suggested.