Abstract
Background/Objectives: Listeria monocytogenes is a major foodborne pathogen of public health concern because of the severe outcomes associated with invasive listeriosis, its ability to persist throughout the food chain, and its capacity to form biofilms. In this study, the occurrence, antimicrobial resistance, antimicrobial resistance genes, and biofilm-forming capacity of L. monocytogenes from food of animal origin in Northern Kazakhstan were investigated, and the association between the biofilm phenotype and antimicrobial resistance was also assessed. Methods: A total of 1561 samples were analyzed. L. monocytogenes was isolated and identified according to ISO 11290-1 and confirmed by MALDI‒TOF MS. Antimicrobial susceptibility was determined by disk diffusion according to EUCAST recommendations. Resistance genes were detected by PCR, and biofilm formation was assessed using a crystal violet assay. Results:L. monocytogenes was detected in 34 (2.18%) samples. Resistance to at least one antimicrobial agent was observed in 18 (52.9%) isolates, with the highest resistance rate observed for trimethoprim–sulfamethoxazole (14/34, 41.2%). Multidrug resistance was detected in 8 (23.5%) isolates and was defined as resistance to at least three antimicrobial classes, including β-lactams, macrolides, and sulfonamides. The most frequently detected resistance genes were msrA (26.5%) and mefA (20.6%). All isolates formed biofilms, with 44.1% classified as strong producers and 55.9% as moderate producers. Strong biofilm formation was significantly associated with antimicrobial resistance (OR = 4.71, p = 0.045). Conclusions: L. monocytogenes was detected in 34 (2.18%) animal-origin food samples from Northern Kazakhstan. The isolates demonstrated antimicrobial resistance and biofilm-forming capacity, with a significant association between strong biofilm formation and antimicrobial resistance. These findings highlight the importance of continued microbiological surveillance of L. monocytogenes in animal-origin foods.