Simultaneous enumeration of E. coli and total coliforms
US6146840A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1994 |
| Grant date | Nov 14, 2000 |
| Priority date | — |
| Expiry date | Apr 29, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2333/245
- WIPO fieldBiotechnology
- WIPO sectorChemistry
Abstract
The general method involves contacting a bacterial colony with a .beta.-D-galactosidase substrate and a carbon source metabolizable by a plurality of coliform species but not metabolizable by E. coli, and detecting reaction product signals of the substrate and carbon source. Typically, the carbon source is a carbohydrate, preferably adonitol, esculin, salicin, amygdalin, or cellobiose. The absence of both reaction product signals indicates the presence of non-coliform bacteria; the presence of both reaction product signals indicates the presence of non-E. coli coliform bacteria; and, the presence of the .beta.-D-galactosidase substrate reaction product signal and absence of the carbon source reaction product signal indicates the presence of E. coli. A signal may identify a reaction product itself (e.g. a colored product derived from a chromogenic form of the substrate or from a chromogenic reagent which interacts with the product, etc.), or an effect of a reaction product on or at the colony (e.g. catabolite repression, growth, localized pH change, etc.). Preferably, the .beta.-D-galactosidase substrate reaction product signal is provided directly by a .beta.-D-galactosidase reacti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.