Investigation of the Genomic and Pathogenic Features of the Potentially Zoonotic .

Recently, reference strains of serotype 20, 22, and 26 were reclassified as . The public health significance of is underestimated due to the lack of clinical isolates. In the present study, we first reported two sporadic infections in humans, after using full-length 16S rRNA and housekeeping genes' phylogeny and ANI values of genome sequence comparisons to determine the species of their isolates BS26 and BS27. Compared to highly pathogenic strain P1/7, strains BS26 and BS27 possessed a delayed capacity to initiate lethal infection, which may attribute to the later production of higher level of pro-inflammatory cytokines. Differed to strain P1/7, strains did not induce significant inflammatory response in the brain of mice. Histopathological changes in liver and lungs were widely present in mice infected with strains. Our data indicated that the pathogenic mechanism of may be different from that of . Three lineages in the core-genome phylogenetic tree and ten types of gene cluster were found in 13 genomes, indicating high heterogeneity of this species. The similarity of CPS structure and antibiotic-resistant genes relative to indicated the evolutionary affinity between the two species. Our data suggested is a potential zoonotic pathogen and poses severe threat to health of susceptible people. Further study on the epidemiology and public health significance of is urgently necessary.