The National Antimicrobial Resistance Monitoring System (NARMS) is a national public health surveillance system through which FSIS partners with state and local public health departments, the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) to track changes in antimicrobial susceptibility of select foodborne bacteria found in ill people (CDC), retail meats (FDA) and food animals (FSIS). The food animal sampling at FSIS focuses on testing food products and intestinal (cecal) contents. Findings from NARMS are annually published as Integrated Reports (IRs). On Feb. 10, 2023, FSIS released a report to highlight Salmonella antimicrobial resistance (AMR) trends from 2014–2019. This report focuses on sustained AMR trends and emerging areas in Salmonella serotypes that are of public health concern.

FSIS’ key findings indicate that:

• The proportion of pan-susceptible Salmonella differed among slaughter classes and sample sources (cecal/product samples): cattle (83%/71%), swine (65%/64%), chicken (35%/43%), and turkey (34%/32%).
• The top Salmonella serotypes for each slaughter class were Kentucky (chicken), Reading (turkey), Montevideo (cattle) and Anatum (swine).
• Salmonella Infantis showed an increasing trend in chicken and emerged as one of the top serotypes in both cecal and product samples.
• Salmonella Infantis from both cecal and product samples showed increased multidrug-resistance.
• Salmonella isolates from chicken cecal and product samples show a significant increase in resistance to the critically important antimicrobial drugs: ciprofloxacin, ceftriaxone and trimethoprim-sulfamethoxazole.
• Over time, Salmonella isolates from product samples from cattle and swine showed increased resistance to cephalosporin.

While the NARMS annual IRs are comprehensive, an in-depth look at the FSIS NARMS data across time provides further insight into sustained AMR changes in food-producing animals. The differences and similarities observed in Salmonella serotypes, for example, and their AMR between cecal and product samples, highlight the importance of monitoring Salmonella from farm-to-slaughter. FSIS continues to explore opportunities to reduce Salmonella and AMR in FSIS-regulated products.

Sources: Uday Dessai, Catherine Rockwell, USDA Food Safety and Inspection Service