Evaluation of the Anderson Baird‐Parker direct plating method for enumerating Escherichia coli in water

Abstract

The direct plating (DP) method for enumerating Escherichia coli in food was adapted for water analysis by membrane filtration and a standardized protocol was described. The DP method was found to give equal or better recoveries of E. coli than a membrane filtration method using 0.1% sodium lauryl sulphate agar; the repeatability of the DP method was markedly better. The necessity to transfer membranes from the non-selective medium tryptone soy agar (TSA) to the selective medium tryptone bile agar (TBA) after pre-incubation for 4 h was considered disadvantageous for practical purposes. A double-layer method, where the membrane filter is placed on a layer of TSA poured over TBA, with incubation in an incubator that automatically switches from 37 degrees to 44 degrees C after 4 h, was found to be an acceptable alternative. Recovery of E. coli and inhibition of competitive flora were equal or only slightly less than for the standard DP method.

Polyurethane rotating disc system for post-treatment of anaerobically pre-treated sewage

“…Total Kjeldahl Nitrogen (TKj-N) was determined according to APHA (2005). E. coli was measured according to the method described by Havelaar and During (1988).…”

Rapid identification of environmental bacterial strains by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

“…Bacteria were counted after 24 h incubation at 37°C. Confirmation of the strain was done by indole production according to the ISO 9308‐1:2000 methods 38–41…”

Comparison of indole production and β-glucuronidase activity for the detection of Escherichia coli in a membrane filtration method

“…A second series of water samples obtained from various surface waters (rivers. canals, recreational lakes and marine waters) were examined by the D P method with the DAB reagent as previously described (Havelaar & During 1988), by the D P method with the James' indole reagent (bioMerieux; no. 70540) and by a method using TBA plates in which MUG (Sigma; no.…”

“…Direct assays for presumptive Escherichia coli are increasingly used to examine water for faecal pollution. The Direct Plating (DP) method (Havelaar & During 1988) is a membrane filter method based on the ability of E. coli to produce indole at 44°C on a selective medium containing bile salts. 8-glucuronidase activity has also frequently been reported as a means of rapid identification of E .…”