Diversity and antimicrobial resistance of Listeria spp. and L. monocytogenes clones from produce handling and processing facilities in the Pacific Northwest

The widespread nature of Listeria monocytogenes and its presence in soil agricultural environments, make it a challenging pathogen to control the produce industry. objective this study was assess diversity spp. isolates (n = 113) previously recovered from five handling processing facilities Pacific Northwest, using molecular antibiogram typing. Antimicrobial resistance (AMR) profiles were obtained for all isolates. L. also characterized serogrouping 75) multi-locus sequence typing (MLST; n 48). Most individual contained single serogroup monocytogenes; two positive 1 only 4 only. facility with highest prevalence both serogroups. MLST identified 10 unique types (STs) within clonal complexes (CCs), hypervirulent clones CC2 CC4 being overrepresented. All sensitive ampicillin, erythromycin, gentamicin, imipenem, co-trimoxazole, tetracycline vancomycin resistant cefoxitin nalidixic acid. A high proportion (66%) clindamycin, whereas penicillin, ciprofloxacin, rifampin, novobiocin less common. Three one innocua isolate multi-drug (MDR; ≥3 antibiotics). While majority remain clinically relevant antibiotics, MDR strains environments is concerning prompts further studies understand pressures driving AMR changes these microorganisms.