ENZYMATIC METHOD FOR DETECTING COLIFORM BACTERIA OR E. COLI

摘要

A two stage enzymatic method for the detection of coliform bacteria or E. coli wherein bacteria are concentrated on a membrane filter. This filter is placed on a growth medium containing nutrients, including preferably minerals, a protein hydrolysate and a sugar, preferably maltose or a polyalcohol, preferably mannitol, an inducer of a marker enzyme, in particular beta -galactosidase or beta -glucuronidase and inhibitors of the growth of competing bacteria. After a preincubation step, the filter is placed on an assay medium containing a fluorogenic or chemiluminogenic enzyme substrate and a membrane permeabilizer. The membrane filter and the assay medium are incubated to allow cleavage of the enzyme substrate producing fluorescent or chemiluminescent microcolonies on the membrane filter after triggering of light emission.