Abundance of culturable versus viable Escherichia coli in freshwater
| Autor: | Josué PratsJ. Prats, Pierre Servais, Julien Passerat, Tamara Garcia-Armisen |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Microbial Viability
biology Aquatic ecosystem Immunology Colony Count Microbial Fresh Water General Medicine biology.organism_classification medicine.disease_cause Applied Microbiology and Biotechnology Microbiology Enterobacteriaceae Fresh water Abundance (ecology) Aquatic environment Genetics Enumeration medicine Escherichia coli Molecular Biology Bacteria |
| Zdroj: | Canadian journal of microbiology. 55(7) |
| ISSN: | 1480-3275 |
| Popis: | Approved methods traditionally used for Escherichia coli enumeration in waters are culture-based. However, these methods can underestimate the E. coli abundance in aquatic systems because they do not take into account cells that remain viable but have lost the ability to grow in or on culture media. We investigated, in freshwater samples, the abundance of (i) culturable E. coli, enumerated by the most probable number microplate method and (ii) viable E. coli, estimated using a procedure called DVC–FISH, which couples fluorescent in situ hybridization (FISH) and a viability testing technique (direct viable count (DVC)). The ratio of culturable to viable E. coli was close to 1 in highly contaminated waters (samples with a high concentration of culturable E. coli), but decreased drastically for weakly contaminated samples. This indicates a large fraction of viable but nonculturable (VBNC) E. coli in the latter samples. Microcosm experiments showed that some environmental factors, such as nutrient scarcity and solar irradiation, could lead to the presence of a high proportion of VBNC E. coli. |
| Databáze: | OpenAIRE |
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