Prevalence, Antimicrobial Resistance, and Genetic Diversity of Listeriaspp. Isolated from Raw Chicken Meat and Chicken-Related Products in Malaysia

Listeriaspp. are ubiquitous in nature and can be found in various environmental niches such as soil, sewage, river water, plants, and foods, but the most frequently isolated species are Listeria monocytogenesand Listeria innocua. In this study, the presence of Listeriaspp. in raw chicken meat and chicken-related products sold in local markets in Klang Valley, Malaysia was investigated. A total of 44 Listeriastrains (42 L. innocuaand 2 L. welshimeri) were isolated from 106 samples. Antibiotic susceptibility tests of the L. innocuastrains revealed a high prevalence of resistance to clindamycin (92.9%), ceftriaxone (76.2%), ampicillin (73.8%), tetracycline (69%), and penicillin G (66.7%). Overall, 31 L. innocuaand 1 L. welshimeristrain were multidrug resistant, i.e., nonsusceptible to at least one antimicrobial agent in three or more antibiotic classes. The majority of the L. innocuastrains were placed into five AscI pulsogroups, and overall 26 distinct AscI pulsotypes were identified. The detection of multidrug-resistant Listeriastrains from different food sources and locations warrants attention because these strains could serve as reservoirs for antimicrobial resistance genes and may facilitate the spread and emergence of other drug-resistant strains.