T7-12 Antimicrobial Resistance in Salmonella Isolated from Food Animals at Slaughter by the Food Safety Inspection Service, USDA

Tuesday, August 2, 2016: 11:45 AM
241 (America's Center - St. Louis)
Jovita Haro, U.S. Department of Agriculture-FSIS-OPHS, Athens, GA
Uday Dessai, U.S. Department of Agriculture-FSIS-OPHS, Washington, DC
Wanda Wilson, U.S. Department of Agriculture-FSIS-OPHS, Washington, DC
Patricia White, U.S. Department of Agriculture-FSIS-OPHS, Washington, DC
Jennifer Sinatra, U.S. Department of Agriculture-FSIS-OPHS, Washington, DC
Introduction: In an effort to better understand antimicrobial resistance (AMR) in food-producing animals, in CY 2013, the Food Safety and Inspection Service (FSIS) partnered with the Food and Drug Administration (FDA) under the National Antimicrobial Resistance Monitoring System (NARMS) to undertake a new cecal sampling program. This serves as a complement to FSIS’s existing Pathogen Reduction/Hazard Analysis and Critical Control Point (PR/HACCP) system sampling program.

Purpose: Cecal sampling provides insight into AMR in food animals without the influence of slaughter and processing interventions. Comparison with PR/HACCP provides valuable understanding of AMR persistence from pre-harvest through slaughter and processing.    

Methods: Samples were collected from establishments nationwide with frequency determined by slaughter volume and analyzed for microbial targets including Salmonella.  Antimicrobial susceptibility testing was performed by broth microdilution and minimum inhibitory concentrations were interpreted using Clinical and Laboratory Standards Institute (CLSI) criteria when available.   Described here are results from resistant Salmonella isolated from cecal (CY2014 n=362, CY2015 n=330) compared to those from PR/HACCP (CY2014 n=266, CY2015 n=636) for CY 2014 and 2015.  Due to sampling design differences, a test of statistical significance was not applied.

Results: Among resistant isolates from both cecal (C) and PR/HACCP (H), few were resistant to azithromycin and ciprofloxacin (<2% [C] and <1% [H]).   Ceftriaxone resistance was lower in cecal than in PR/HACCP in both 2014 (11.9% [C] and 18.8% [H]) and 2015 (11.8% [C] and 14.3% [H]). Streptomycin resistance, mostly attributed to chicken, was also found less frequently among resistant cecal isolates (< 54%) than in PR/HACCP (> 75%).  Distribution differences by region and establishment size are further described.

Significance: AMR differences were observed not only between cecal and PR/HACCP but also among commodities sampled. AMR in isolates from PR/HACCP may be influenced by in-plant processing factors, while resistance among cecal isolates may reflect on-farm antimicrobial usage.