Title |
Pathogenomics of Streptococcus ilei sp. nov., a newly identified pathogen ubiquitous in human microbiome |
Author |
Dong-Wook Hyun1, Jae-Yun Lee1, Min-Soo Kim1, Na-Ri Shin1, Tae Woong Whon1, Kyung Hyun Kim2, Pil Soo Kim1, Euon Jung Tak1, Mi-Ja Jung1, June Young Lee1, Hyun Sik Kim1, Woorim Kang1, Hojun Sung1, Che Ok Jeon2, and Jin-Woo Bae1 |
Address |
1Department of Biology, Department of Biomedical and Pharmaceutical Sciences, and Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul 02447, Republic of Korea, 2Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea |
Bibliography |
Journal of Microbiology, 59(8),793-806, 2021,
|
DOI |
10.1007/s12275-021-1165-x
|
Key Words |
Streptococcus, Streptococcus ilei, ileum, ileostomy
effluent, virulence factor, pathogenicity, viridans group streptococci,
mitis group streptococci |
Abstract |
Viridans group streptococci are a serious health concern because
most of these bacteria cause life-threatening infections,
especially in immunocompromised and hospitalized individuals.
We focused on two alpha-hemolytic Streptococcus
strains (I-G2 and I-P16) newly isolated from an ileostomy
effluent of a colorectal cancer patient. We examined their pathogenic
potential by investigating their prevalence in human
and assessing their pathogenicity in a mouse model. We also
predicted their virulence factors and pathogenic features by
using comparative genomic analysis and in vitro tests. Using
polyphasic and systematic approaches, we identified the isolates
as belonging to a novel Streptococcus species and designated
it as Streptococcus ilei. Metagenomic survey based on
taxonomic assignment of datasets from the Human Microbiome
Project revealed that S. ilei is present in most human
population and at various body sites but is especially abundant
in the oral cavity. Intraperitoneal injection of S. ilei was
lethal to otherwise healthy C57BL/6J mice. Pathogenomics
and in vitro assays revealed that S. ilei possesses a unique set
of virulence factors. In agreement with the in vivo and in vitro
data, which indicated that S. ilei strain I-G2 is more pathogenic
than strain I-P16, only the former displayed the streptococcal
group A antigen. We here newly identified S. ilei sp.
nov., and described its prevalence in human, virulence factors,
and pathogenicity. This will help to prevent S. ilei strain
misidentification in the future, and improve the understanding
and management of streptococcal infections. |