To evaluate the molecular epidemiological characteristics and potential risks of foodborne Listeria monocytogenes in Jiayuguan City, Gansu Province.

This study analyzed the population structure,virulence factor profiles, and genetic evolutionary relationships of local strains at the genomic level. Whole-genome sequencing was performed on 4 strains of Listeria monocytogenes isolated from food in Jiayuguan City. Bioinformatics methods were used for molecular typing and serotype prediction, systematic screening of virulence and resistance genes,and through average nucleotide identity (ANI) analysis and the construction of core genomic phylogenetic trees, the genetic similarity and evolutionary localization among strains were analyzed.

The 4 strains belonged to 4 sequence types: ST8, ST121, ST91 and ST9. All strains carried complete core virulence gene clusters and the invasion gene inlA. The ST121 strain exhibited deletion of the actA gene and an incomplete LIPI-1 virulence island. Average nucleotide identity and phylogenetic analysis showed that the ST9 strain formed a tight clonal group with specific reference strains; the ST8 strain was highly homologous to a clinical strain (ANI: 99.78%) and clustered closely on the phylogenetic tree.

This study confirmes the genetic diversity of foodborne Listeria monocytogenes in Jiayuguan City and their possession of complete core virulence gene clusters. Among them, the ST8 clone showes high homology with clinical strains, indicating a clear risk of food-to-human transmission. The findings provide critical data support for establishing a genomics-based prospective early warning system for food safety risks in the region.