Application of a DNA Hybridization–Hydrophobic-Grid Membrane Filter Method for Detection and Isolation of Verotoxigenic Escherichia coli
| Autor: | A. Martin, E. C. D. Todd, Kris Rahn, Arlene Yee, J. M. MacKenzie, A. Gao, R. A. Szabo, Carlton L. Gyles, David Alves |
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| Rok vydání: | 1999 |
| Předmět: |
Meat
Bacterial Toxins Escherichia coli O157 Shiga Toxin 1 medicine.disease_cause Polymerase Chain Reaction Applied Microbiology and Biotechnology law.invention Microbiology Beverages Birds Feces chemistry.chemical_compound fluids and secretions law Vegetables medicine Animals Food microbiology Escherichia coli Polymerase chain reaction Mammals Ecology biology Deer food and beverages biology.organism_classification Enterobacteriaceae chemistry VTEC Fruit Food Microbiology MacConkey agar Bacteria Food Science Biotechnology |
| Zdroj: | Applied and Environmental Microbiology. 65:4775-4780 |
| ISSN: | 1098-5336 0099-2240 |
| DOI: | 10.1128/aem.65.11.4775-4780.1999 |
| Popis: | Verotoxigenic Escherichia coli (VTEC) strains were isolated from food and animal fecal samples by using PCR to screen for the presence of VTEC after broth enrichment and then filtering VTEC-positive cultures through hydrophobic-grid membrane filters (HGMFs) which were incubated on MacConkey agar. The filters were probed with a digoxigenin-labeled PCR product generated by amplification of a conserved verotoxin gene sequence. Replication of the growth on filters allowed probe-positive colonies to be picked. When ground beef samples were inoculated with VTEC strains, 100% of the strains were recovered, and the detection limit was 0.1 CFU per g. Similar results were obtained with seven types of artificially contaminated vegetables. A survey of 32 packages of vegetables and 23 samples of apple cider obtained at the retail level did not reveal the presence of VTEC. However, the intestinal fecal contents of a moose, 1 of 35 wild mammals and birds examined, contained E. coli O157:H7. The DNA hybridization-HGMF method was also used in a prevalence survey of 327 raw and 744 ready-to-eat products; VTEC strains were recovered from 4.9% of the raw products and 0.7% of the ready-to-eat products. No serotype O157:H7 strains were detected. This method is particularly suited for surveys in which low numbers of VTEC-positive samples are expected and isolates are required. |
| Databáze: | OpenAIRE |
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