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United States Department of Agriculture

Agricultural Research Service

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Research Project: Prevalence and Enumeration of Antimicrobial Resistant Escherichia Coli and Salmonella Throughout the Beef Production Continuum

Location: Meat Safety & Quality Research

Project Number: 5438-42000-014-08
Project Type: Trust

Start Date: Oct 01, 2013
End Date: Sep 30, 2014

Objective:
The objectives of this research are to determine the prevalences and concentrations of extended-spectrum cephalosporin-resistant Salmonella and E. coli, quinolone-resistant Salmonella, and trimethoprim-sulfamethoxazole-resistant E. coli throughout the beef continuum from production, through processing, to final product and to determine the effectiveness of currently used processing interventions on the reduction of these antimicrobial resistant bacteria.

Approach:
The prevalence and concentrations of extended-spectrum cephalosporin-resistant Salmonella and E. coli, quinolone-resistant Salmonella, and E. coli, and trimethoprim-sulfamethoxazole-resistant E. coli for 150 cattle will be determined on fecal swab and hide samples from cattle at the feedlot taken within 30 days of harvest; fecal and hide samples during harvest at a processing plant; pre-evisceration carcass samples; final carcass samples; and sub-primal products. Prevalence and enumeration and isolation of resistant Salmonella and E. coli will be determined by standard procedures in our lab. From each sample presumptive Salmonella colonies will be confirmed by PCR for the invA gene. From each sample presumptive E. coli colonies will be confirmed by multiplex PCR for uidA, cyd, lacY, and lacZ genes. Five hundred confirmed isolates drawn proportionally from all sample types and split equally between confirmed E. coli and confirmed Salmonella isolates will be subjected to antimicrobial susceptibility testing for 15 antimicrobial agents and detailed genetic characterization including PCR to identify genes conferring antimicrobial resistance.

Last Modified: 9/10/2014
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