Analysis of 90 Listeria monocytogenes contaminated in poultry and livestock meat through whole-genome sequencing

Listeria monocytogenes is a food-borne pathogen that can cause human listeriosis. The main cause of L.monocytogenes poisoning is the consumption of contaminated or processed foods, of which meat is the main one. At present, it is not clear whether the listeria contaminated in different meat is genetically diverse. In this study, a total of 90 L.monocytogenes isolates including 28 isolates in livestock meat and 62 isolates in poultry meat were obtained from chicken, duck, pork, and beef respectively in Beijing. And whole-genome sequencing (WGS) based analysis was performed to investigate the genetic diversity of L.monocytogenes between poultry and livestock meat isolates. As a result, we found the prevalence of the multilocus sequence typing (MLST)-derived clonal complexes (CCs) were quite different between two different types of meat. The number of resistance genes and virulence genes in most of the L.monocytogenes isolated from the four meat species were close, but the sequences of eight resistance genes and 19 virulence genes were significantly varied between poultry meat and livestock meat. The phylogenetic and collinear analysis of these isolates revealed the isolates in the same meat have a similar genome. These results showed that the genetic variation of L.monocytogenes in livestock and poultry meat were significantly different isolates.