Toward the Adoption of Loop-Mediated Isothermal Amplification for Salmonella Screening at the National Antimicrobial Resistance Monitoring System's Retail Meat Sites.

The National Antimicrobial Resistance Monitoring System (NARMS) is a One Health program in the United States that collects data on antimicrobial resistance in enteric bacteria from humans, animals, and the environment. is a major pathogen tracked by the NARMS retail meat arm but currently lacks a uniform screening method. We evaluated a loop-mediated isothermal amplification (LAMP) assay for the rapid screening of from 69 NARMS retail meat and poultry samples. All samples were processed side by side for culture isolation using two protocols, one from NARMS and the other one described in the U.S. Food and Drug Administration's (BAM). Overall, 10 (14.5%) samples screened positive by the LAMP assay. Of those, six were culture-confirmed by the NARMS protocol and six by the BAM method with overlap on four samples. No isolates were recovered from samples that screened negative with LAMP. These results suggested 100% sensitivity for LAMP in reference to culture. Antimicrobial susceptibility testing and whole-genome sequencing analysis confirmed identities of these isolates. Using the BAM protocol, all isolates were recovered from samples undergoing Rappaport-Vassiliadis medium selective enrichment and presumptive colonies ( = 130) were dominated by (44.6%), (22.3%), and (9.9%) based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This method comparison study clearly demonstrated the benefit of a rapid, robust, and highly sensitive molecular screening method in streamlining the laboratory workflow. Fourteen NARMS retail meat sites further verified the performance of this assay using a portion of their routine samples, reporting an overall specificity of 98.8% and sensitivity of 90%. As of July 2022, the vast majority of NARMS retail meat sites have adopted the LAMP assay for rapid screening of in all samples.