Molecular characteristics of Yersinia enterocolitica and related species in Ningxia, China based on whole-genome sequencing

Abstract Background: Yersinia enterocolitica is a common zoonotic pathogen and has emerged as an important foodborne pathogen worldwide. Y. enterocolitica has been sporadically recovered from animals, foods, and human clinical samples in various regions of Ningxia. Molecular characteristics of Y. enterocolitica in the Ningxia Hui Autonomous Region was not well described in current studies.Methods: The molecular characteristics of 271 Yersinia strains isolated from the Ningxia Hui Autonomous Region were analyzed using SNP and core gene multilocus sequence typing (cgMLST). The isolates were taken from animals (n = 208), food (n = 50), and patients (n = 13) between 2007 and 2019. Results: The SNP results indicated that the 271 isolates were divided into 12 species, Y. enterocolitica (n=187), Y. intermedia (n=31), Y. massiliensis (n=30), Y. mollaretii (n=7), Y. pekkanenii (n=5), Y. proxima (n=4), Y. alsatica (n=2), Y. frederiksenii (n=1), Y. kristensenii (n=1), Y. hibernica (n=1), Y. canariae (n=1), and Y. rochesterensis (n=1). Of the 187 Y. enterocolitica isolates, 81.28% (n = 152) were of animal origin, the food source was 12.30% (n = 23) and the patient source was 6.42% (n = 12). The clustering of Y. enterocolitica strains were closely related to the biotype. In total, 187 Y. enterocolitica strains were classified into 54 sequence types (STs) and 125 cgMLST types (CTs). The most common STs were ST429, which were significantly associated with serotype O:3. 4/O:3 was the dominant bioserotype in the Ningxia region, which differed from most of China. The 125 CTs clustered to form 55 microclades of the HC100 (hierarchical clustering). Conclusion: The results indicated that the distribution of Y. enterocolitica in the Ningxia Hui Autonomous Region was both general and specific and differed to some extent from the distribution elsewhere in China and abroad. The difference in the distribution of virulence genes between pathogenic and non-pathogenic isolates was attributed to the presence or absence of the type III secretion system. Swine farming and meat food cause human infection and transmission.