Colorimetric enumeration of Escherichia coli based on beta-glucuronidase activity
| Autor: | Martin R. Adams, S M Grubb, Michael N. Clifford, A Hamer |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Sodium
Population Colony Count Microbial chemistry.chemical_element Glucuronates medicine.disease_cause Applied Microbiology and Biotechnology Nitrophenols Escherichia coli medicine Enumeration education Colorimetry Glucuronidase education.field_of_study Chromatography Ecology biology Chromogenic Chemistry Beta-glucuronidase activity biology.organism_classification Enterobacteriaceae Chromogenic Compounds Biochemistry Evaluation Studies as Topic Water Microbiology Research Article Food Science Biotechnology |
| Zdroj: | Applied and Environmental Microbiology. 56:2021-2024 |
| ISSN: | 1098-5336 0099-2240 |
| DOI: | 10.1128/aem.56.7.2021-2024.1990 |
| Popis: | A medium containing a chromogenic substrate was developed for the enumeration of Escherichia coli on the basis of beta-glucuronidase activity. In this medium there was an inverse linear relationship between the log initial E. coli concentration and the time taken for the color to reach a threshold optical density of 0.05. This relationship applied even when the E. coli population contained 5% beta-glucuronidase-negative cells. Incubation at 44 degrees C reduced the time taken for color development and allowed the procedure to be used in the presence of a competitive microflora that outnumbered the E. coli population by a factor of 10(4). Sodium lauryl sulfate as an additional selective agent gave no significant improvement. In the analysis of environmental water samples, the technique gave a good correlation with a standard cultural method. The procedure shows promise as a simple method for testing the compliance of environmental samples with microbiological criteria for E. coli. |
| Databáze: | OpenAIRE |
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