Journal of Microbiology

Woorim Kang

1 Article

Pathogenomics of Streptococcus ilei sp. nov., a newly identified pathogen ubiquitous in human microbiome: Dong-Wook Hyun , Jae-Yun Lee , Min-Soo Kim , Na-Ri Shin , Tae Woong Whon , Kyung Hyun Kim , Pil Soo Kim , Euon Jung Tak , Mi-Ja Jung , June Young Lee , Hyun Sik Kim , Woorim Kang , Hojun Sung , Che Ok Jeon , Jin-Woo Bae; J. Microbiol. 2021;59(8):793-806.; DOI: https://doi.org/10.1007/s12275-021-1165-x

70 View
0 Download
9 Web of Science
9 Crossref

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.

Citations

Citations to this article as recorded by

Microbiota analysis of perimenopausal women experiencing recurrent vaginitis in conjunction with urinary tract infection
Yingying Bi, Yuezhu Wang, Wu Li, Yuhang Chen, Jinlong Qin, Huajun Zheng
BMC Microbiology.2025;[Epub] CrossRef
Characterization of blood microbial population in beef calves with clinical signs of sepsis using 16S rRNA gene sequencing
Giuliano Borriello, Flaminia Valentini, Sara Ferrini, Giorgia Di Muro, Giulia Cagnotti, Elena Grego, Angela Maria Catania, Maria Cristina Stella, Ugo Ala, Patrizia Nebbia, Antonio D’Angelo, Claudio Bellino, Ulrike Gertrud Munderloh
PLOS One.2025; 20(5): e0324469. CrossRef
Molecular characterization of a novel putative pathogen, Streptococcus nakanoensis sp. nov., isolated from sputum culture
Takeaki Wajima, Takashi Sugawara, Emi Tanaka, Kei-ichi Uchiya, Justin R. Kaspar
Microbiology Spectrum.2024;[Epub] CrossRef
Streptococcus raffinosi sp. nov., isolated from human breast milk samples
Ha Viet Nguyen, Anh Thi Van Trinh, Linh Nguyen Hai Bui, Anh Thi Lan Hoang, Quyen Thi Le Tran, Trung Thanh Trinh
International Journal of Systematic and Evolutionary Microbiology .2024;[Epub] CrossRef
Description of Streptococcus dentalis sp. nov., Streptococcus gingivalis sp. nov., and Streptococcus lingualis sp. nov., Isolated from Human Oral Cavities
Beom-Jin Goo, Young-Sik Choi, Do-Hun Gim, Su-Won Jeong, Jee-Won Choi, Hojun Sung, Jae-Yun Lee, Jin-Woo Bae
Journal of Microbiology.2024; 62(11): 973. CrossRef
Valid and accepted novel bacterial taxa derived from human clinical specimens and taxonomic revisions published in 2022
Erik Munson, Arianna Carella, Karen C. Carroll, Romney M. Humphries
Journal of Clinical Microbiology.2023;[Epub] CrossRef
Valid publication of new names and new combinations effectively published outside the IJSEM. Validation List no. 203
Aharon Oren, George M. Garrity
International Journal of Systematic and Evolutionary Microbiology .2022;[Epub] CrossRef
Modulation of gut microbiota and fecal metabolites by corn silk among high-fat diet-induced hypercholesterolemia mice
Lin Ding, Shan Ren, Yaoxin Song, Chuangang Zang, Yuchao Liu, Hao Guo, Wenqing Yang, Hong Guan, Jicheng Liu
Frontiers in Nutrition.2022;[Epub] CrossRef
Reclassification of Streptococcus ilei as a later heterotypic synonym of Streptococcus koreensis based on whole-genome sequence analysis
Sanjeet Kumar, Kanika Bansal, Santosh Kumar Sethi
Archives of Microbiology.2022;[Epub] CrossRef

Woorim Kang

1 Article

Bacteroides celer sp. nov. and Bacteroides mucinivorans sp. nov., isolated from human feces, and the reclassification of Bacteroides koreensis Shin et al. 2017 and Bacteroides kribbi Shin et al. 2017 as later heterotypic synonyms of Bacteroides ovatus Eggerth and Gagnon 1933 (Approved Lists 1980): Ah-In Yang, Bora Kim, Woorim Kang, Hae-In Joe, Na-Ri Shin; Received February 7, 2025 Accepted April 28, 2025 Published online May 22, 2025; DOI: https://doi.org/10.71150/jm.2502006

0 View
0 Download

Abstract: Two novel, Gram-stain-negative, anaerobic, and non-motile bacterial strains, designated KFT8^T and CG01^T, were isolated from the feces of healthy individuals without diagnosed diseases and characterized using a polyphasic approach. Phylogenetic analysis revealed that both strains belong to the genus Bacteroides, with < 99.0% similarity in their 16S rRNA gene sequences to B. facilis NSJ-77^T and B. nordii JCM 12987^T. Within the genus Bacteroides, strain KFT8^T exhibited the highest Orthologous Average Nucleotide Identity value of 94.7% and a digital DNA-DNA hybridization value of 63.7% with B. ovatus ATCC 8483^T, whereas strain CG01^T showed the highest values of 95.3% and 63.3%, respectively, with B. nordii JCM 12987^T. The values between the two novel strains were 74.8% and 21.4%, respectively, which are below the species delineation thresholds, supporting their classification as novel species. The major fatty acid of strain KFT8^T was C_18:1 ω9c, whereas strain CG01^T predominantly contained summed feature 11 (comprising iso-C_17:0 3OH and/or C_18:2 DMA). The only respiratory quinone was MK-11, the major polar lipid was phosphatidylethanolamine. Both strains produced succinic acid and acetic acid as common metabolic end-products of fermentation, while lactic acid and formic acid were detected individually in each strain. Based on polyphasic characterization, strains KFT8^T (= KCTC 15614^T = JCM 36011^T) and CG01^T (= KCTC 15613^T = JCM 36010^T) represent two novel species within the genus Bacteroides, for which the names Bacteroides celer sp. nov. and Bacteroides mucinivorans sp. nov. are proposed, respectively. Additionally, genome-based analyses and phenotypic comparisons revealed that B. koreensis and B. kribbi represent the same strain, showing genomic relatedness to B. ovatus that exceeds the threshold for species delineation. Consequently, we propose the reclassification of B. koreensis Shin et al. 2017 and B. kribbi Shin et al. 2017 as later heterotypic synonyms of B. ovatus Eggerth and Gagnon 1933 (Approved Lists 1980).

Author index