The Wild Mouse (): Reservoir of a Novel Strain.

is one of the most common zoonotic pathogens worldwide. Although the main sources of human infection are livestock, wildlife can also affect transmission in humans. However, it remains unclear whether wild mice harbor and are involved in the "environment-wildlife-livestock-human" transmission cycle of in humans. Here, we characterized from wild mice and identified genetic traces of wild mouse-derived in other hosts using a traditional approach, along with comparative genomics. We captured 115 wild mice (49 and 66 ) without any clinical symptoms from 22 sesame fields in Korea over 2 years. Among them, were typically caught in remote areas of human houses and was solely isolated from (42/66, 63.6%). We identified a single clone (MLST ST-8388) in all 42 isolates, which had not been previously reported, and all isolates had the same virulence/survival-factor profile, except for the plasmid-mediated B11 gene. No isolates exhibited antibiotic resistance, either in phenotypic and genetic terms. Comparative-genomic analysis and MST revealed that derived from (strain SCJK2) was not genetically related to those derived from other sources (registered in the NCBI genome database and PubMLST database). Therefore, we hypothesize that from is a normal component of the gut flora following adaptation to the gastro-intestinal tract. Furthermore, -derived had different ancestral lineages from those derived from other sources, and there was a low chance of transmission from to humans/livestock because of their habitat. In conclusion, may be a potential reservoir for a novel , which is genetically different from those of other sources, but may not be involved in the transmission of to other hosts, including humans and livestock. This study could form the basis for further studies focused on understanding the transmission cycle of , as well as other zoonotic pathogens originating from wild mice.