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Isolation & Identification of E. Coli 0157:H7 in Feral Swine Samples

Mandrell, Robert
USDA - Agricultural Research Service
Start date
End date
To determine the prevalence of E.coli O157:H7 in wild pigs and other wildlife species from thethree central coastal counties in California.

The objective is to identify wild pig herds and other wildlife speciaes that may carry pathogenis O157:H7 and could potentially be a contamination source to nearby vegatable crops.

The goal is to use good scientific results to develop educational information, management plans and policies to decrease the food safety conflict between the vegatable industry and wildlife.

More information
APPROACH: USDA-ARS PSMRU will receive samples of feral swine feces or tissue periodically. These samples will be analyzed for the presence of E. coli O157:H7 by microbiological procedures. The samples will be added to a broth medium for non-selective enrichment, then immunomagnetic beads will be added to capture O157 cells, then the beads will be plated on both Rainbow Agar (Biolog) and TC-SMAC for overnight growth. The next day plates will be examined and suspect colonies will be picked for further analysis and confirmation by PCR and immunochemical methods. The presence of E. coli O157:H7 can be determined with ~95% certainty after four days from the start of the isolation procedure. Confirmation of the isolates as E. coli O157:H7 requires PCR analysis for sixe different genes/virulence factors, which will require an additional three days. Therefore, confirmed results can be obtained in seven days.
Funding Source
Agricultural Research Service
Project number
Accession number
Natural Toxins
Viruses and Prions
Bacterial Pathogens
Chemical Contaminants
Escherichia coli
Policy and Planning