Rapid detection of Escherichia coli in urine samples by a new chromogenic beta-glucuronidase assay

Abstract

A new compound, indoxyl-p-D-glucuronide, was assessed as a substrate for the rapid detection ofEscherichia coli in urine. Incorporation of this compound into MacConkey agar allowed the direct differentiation of E. coli as deep blue colonies distinct from lactose and nonlactose fermenters. The sensitivity was 88 to 90%, and the specificity was 100%.

Evaluation of new medium with chromogenic substrates for members of the family Enterobacteriaceae in urine samples

“…The sensitivity value for E. coli by our results is 9.7% higher than that of Delisle and Ley (2), and the colony color of E. coli on Glu agar was clearer than that of E. coli on MacConkey agar.…”

“…The latter include members of the genera Cedecea, Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Kluyvera, Rahnella, Salmonella III, Serratia, and Yersinia. Recently, chromogenic substrate assays based on the enzymatic activities of ␤-glucuronidase for the rapid identification of E. coli in urine (2), food (4,15,16), and water (6,10,16) and that of ␤-galactosidase for the coliform group in food (5) and water (12) have been assessed. However, 5-bromo-4-chloro-3-indolyl-␤-D-glucuronide cyclohexylammonium salt (13,15,16) for E. coli and 5-bromo-3-indolyl-␤-D-galactoside (5,12) for ␤-galactosidase-positive Enterobacteriaceae have not been evaluated directly for use with urine samples.…”

Evaluation of CPS ID2 medium for detection of urinary tract bacterial isolates in specimens from a rehabilitation center

“…As with CPS ID2 medium, chromogenic substrates have been used previously to avoid the need to use of UV light. The nonsoluble colored compounds obtained were intended not to diffuse into the agar (6).…”

Enzyme capture assay for rapid identification of Escherichia coli in blood cultures

“…(50 ,ug/ml) dissolved in 0.2 M phosphate buffer, pH 6.5. After 10 to 15 min of incubation at room temperature, the blue band corresponding to the position of GUD was visible (6). The band was cut from the gel with a razor and used for antibody production.…”

“…Since 1976, when Kilian and Bulow (17) described the activity of a 3-D-glucuronidase (GUD) as being restricted to Escherichia, Shigella, and Salmonella spp., this property has been widely used for the detection and identification of E. coli (6,9,11,16,30) in food and in clinical microbiology laboratories. Most studies incorporated 4-methylumbelliferyl-,3-Dglucuronide (MUG) as a fluorogenic substrate of GUD in the medium.…”