Molecular characterization and contamination of Listeria monocytogenes in raw meat sold in Xuzhou city

Abstract

ObjectiveThis study aimed to analyze the relevance ratio and molecular biological characteristics of Listeria monocytogenes （L. monocytogenes） in raw meat sold in Xuzhou city in both 2018 and 2020.MethodsRetail fresh and frozen raw poultry， as well as prepared meat， were randomly sampled from urban areas， and L. monocytogenes were isolated and identified following the guidelines of GB 4789.30-2016. The study analyzed serotypes， drug resistance patterns， virulence genotypes， and molecular typing through pulsed field gel electrophoresis （PFGE）.ResultsOut of 142 raw meat samples collected from the market， 40 tested positive for L. monocytogenes， resulting in a prevalence rate of 28.2% （40/142）. The predominant serotype was 1/2a， accounting for 47.5% （19/40） of the isolates. Molecular typing using PFGE revealed 15 distinct PFGE types among the 40 L. monocytogenes strains. Additionally， 4 strains exhibited resistance to ampicillin， and 2 strains were resistant to penicillin. All strains carried multiple virulence genes.ConclusionThis study highlighted the relatively high contamination of L. monocytogenes in raw meat sold in urban Xuzhou. The presence of small-scale homologous strains emphasizes the importance of enhanced monitoring and management to prevent foodborne diseases.

Keywords

• listeria monocytogenes
• pulsed field gel electrophoresis
• virulence genes
• serotypes
• drug resistance