Membrane Filter Procedure for Enumerating the Component Genera of the Coliform Group in Seawater

Abstract

A facile, quantitative, membrane filter procedure (mC) for defining the distribution of coliform populations in seawater according to the component genera was developed. The procedure, which utilizes a series of in situ substrate tests to obviate the picking of colonies for identification, also provides an estimate of the total coliform density. When pure cultures of Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae were suspended in seawater and held at 4 C for 24 h, between 56 and 100% of the cells which grew on nutrient agar spread plates at 35 C could be recovered by the mC procedure. Confirmation as coliforms of typical colonies from natural samples was about 95%. Assay variability was found to be insignificant. The recovery of coliforms from marine waters by the mC procedure was comparable to those obtainable by current methods. Klebsiella was differentiated by the urease reaction and E. coli by its ability to form indole. The confirmation frequencies for colonies designated as Klebsiella and E. coli by the in situ tests approached 95% for the former and 98% for the latter.

Isolation and Enumeration of Listeria monocytogenes from Sewage, Sewage Sludge and River Water

“…Faecal coliforms were isolated by membrane filtration (Oxoid Nuflow membranes, 0.45 pm pore size, 47 mm diameter) using Membrane Enriched Teepol Broth (Oxoid) with incubation at 25°C for 4 h, and 37°C overnight. Faecal coliforms were identified with a modification of the method of Dufour & Cabelli. (1975), incubating at 44°C instead of 22°C.…”

Isolation and Characterization of Bacteria from the Baltic Sea

“…During this period, samples were withdrawn, diluted in sterile ASW and 0.1 ml of suitable dilutions spread on mC medium (Dufour & Cabelli 1975) in Petri dishes and on to nutrient agar prepared with ASW. The number of colonies was counted after 1 d incubation at 35 "C (2 d for Yer.…”

“…2). For experiments on survival, two recovery media were used, nutrient agar prepared with ASW and the mC medium of Dufour & Cabelli (1975) designed for recovery of 'coliforms' stressed by exposure to seawater. When cells of Esch.…”

Poor specificity of m-Endo and m-FC culture media for the enumeration of coliform bacteria in sea water

“…Other authors consider that the determination of E. colt directly provides a more accurate indication of faecal pollution (Dufour and Cabelli 1975;Capleans and Kanarek 1984;Freier and Hartman 1987;Hernandez et al 1991) and in this sense new techniques have been described for the rapid and easy detection of E. coli in recreational waters, based on the p-glucuronidase activity, e.g. MUG, Autoanalysis Colilert, microtitration plates, etc.…”