Evaluation of the β-Glucuronidase Substrate 5-Bromo-4-Chloro-3-Indolyl-β-D-Glucuronide (X-GLUC) in a 24-Hour Direct Plating Method for Escherichia coli

Abstract

A 24-h direct plating method for Escherichia coli using Peptone-Tergitol agar was used to compare the effectiveness of the chromogenic substrate 5-bromo-4-chloro-3-indolyl-β-D-glucuronide (X-GLUC) with the fluorogenic substrate 4-methylumbelliferyl-β-D-glucuronide (MUG) for β-glucuronidase activity. Values obtained for enumeration of two strains of E. coli recovered from artificially inoculated raw minced chicken (i.e., plating efficiencies on the inoculum, cells per g, and recovery percentages elated to those on Plate Count Agar) indicate that X-GLUC at 50 μg/ml was as effective as MUG in an agar medium. Unlike MUG, X-GLUC does not require ultraviolet light illumination, and the color reaction produced remains localized in the positive colonies.

Molecular Epidemiology of Antimicrobial-Resistant CommensalEscherichia coliStrains in a Cohort of Newborn Calves

“…Samples were diluted 1:10 in maximum recovery diluent (Oxoid), and 10 l was spread onto nonselective (antibiotic-free) and antibiotic-containing plates and incubated overnight at 44°C. Characteristic E. coli colonies of a dark blue color were recorded, indicative of the presence of the enzyme glucuronidase (18). The reference strains E. coli NCTC 10418, NCTC 11560, JR 225, and NCTC 12900 were used to confirm the activity of antibiotic-containing plates.…”

Microbiological Quality of Fresh Vegetables and Fruits Collected from Supermarkets in Istanbul, Turkey

“…For each selected dilution, 0.1 ml of sample was spread-plated onto brilliance E. coli/coliform agar (Oxoid, Cambridge, UK). The plates were incubated at 37 °C for 24 h, following which, the number of pink (coliform) and purple (presumptive E. coli) colonies was counted [33]. Identification of E. coli was carried out with IMVIC tests [34].…”

Determination of Escherichia coli Contamination with Chromocult Coliform Agar Showed a High Level of Discrimination Efficiency for Differing Fecal Pollution Levels in Tropical Waters of Kampala, Uganda

“…Recently, application of defined substrate medium technology with particular selective growth conditions and the simultaneous detection of ␤-D-galactosidase and ␤-D-glucuronidase activity have become widespread tools for the detection of E. coli in water and wastewater (3,4,7,21,26). In fact, CCA has proven to be efficient for E. coli detection in temperate regions (1,10,14,19). The results of this study proved that CCA could be applied successfully to tropical waters as well (i.e., in Kampala, Uganda).…”

“…Bottles that turned black due to sulfite reduction were considered to contain samples that were positive for SASF (11). The surface plate technique was used for simultaneous detection of total coliforms (TCC) and E. coli with Chromocult coliform agar (CCA) (1,10,19) which was enriched with 5 mg of cefsulodin (Sigma, Vienna, Austria) per ml. Portions (100 l) of the respective sample dilutions (10 Ϫ1 to 10 Ϫ4 ) were applied to plates (triplicate plates for each dilution step) and incubated at 37°C for 24 h. Pink colonies resulting from salmon-galactoside cleavage by ␤-D-galactosidase were classified as TCC, whereas dark blue colonies resulting from salmon-galactoside and X-glucuronide cleavage by ␤-D-galactosidase and ␤-D-glucuronidase were classified as presumptive E. coli colonies.…”