Virulence Comparison of Subsp. Isolates from Chicken and Whole Genome Analysis of the High Virulent Strain . Enteritidis 211.

BACKGROUND

is one of the common pathogens in both humans and animals that causes salmonellosis and threatens public health all over the world.

METHODS AND RESULTS

Here we determined the virulence phenotypes of nine subsp. () isolates in vitro and in vivo, including pathogenicity to chicken, cell infection, biofilm formation and virulence gene expressions. . Enteritidis 211 (SE211) was highly pathogenic with notable virulence features among the nine isolates. The combination of multiple virulence genes contributed to the conferring of the high virulence in SE211. Importantly, many mobile genetic elements (MGEs) were found in the genome sequence of SE211, including a virulence plasmid, genomic islands, and prophage regions. The MGEs and CRISPR-Cas system might function synergistically for gene transfer and immune defense. In addition, the neighbor joining tree and the minimum spanning tree were constructed in this study.

CONCLUSIONS

This study provided both the virulence phenotypes and genomic features, which might contribute to the understanding of bacterial virulence mechanisms in subsp. . The first completed genomic sequence for the high virulent . Enteritidis isolate SE211 and the comparative genomics and phylogenetic analyses provided a preliminary understanding of genetics and laid the foundation for further study.