Comparative genomics inferred two distinct populations of piscine pathogenic Streptococcus agalactiae, serotype Ia ST7 and serotype III ST283, in Thailand and Vietnam

Pattanapon Kayansamruaj; Chayanit Soontara; Sasimanas Unajak; Ha Thanh Dong; Channarong Rodkhum; Hidehiro Kondo; Ikuo Hirono; Nontawith Areechon

doi:10.1016/j.ygeno.2018.11.016

Comparative genomics inferred two distinct populations of piscine pathogenic Streptococcus agalactiae, serotype Ia ST7 and serotype III ST283, in Thailand and Vietnam

Genomics. 2019 Dec;111(6):1657-1667. doi: 10.1016/j.ygeno.2018.11.016. Epub 2018 Nov 17.

Authors

Pattanapon Kayansamruaj¹, Chayanit Soontara², Sasimanas Unajak³, Ha Thanh Dong⁴, Channarong Rodkhum⁵, Hidehiro Kondo⁶, Ikuo Hirono⁶, Nontawith Areechon²

Affiliations

¹ Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand. Electronic address: pattanapon.k@ku.th.
² Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand.
³ Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand.
⁴ Department of Science, Faculty of Science and Technology, Suan Sunandha Rajabhat University, Bangkok, Thailand.
⁵ Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand; Research Unit of Fish Infectious Diseases (RU-FIDs), Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
⁶ Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Tokyo, Japan.

PMID: 30453061
DOI: 10.1016/j.ygeno.2018.11.016

Abstract

The genomes of Streptococcus agalactiae (group B streptococcus; GBS) collected from diseased fish in Thailand and Vietnam over a nine-year period (2008-2016) were sequenced and compared (n = 21). Based on capsular serotype and multilocus sequence typing (MLST), GBS isolates are divided into 2 groups comprised of i) serotype Ia; sequence type (ST)7 and ii) serotype III; ST283. Population structure inferred by core genome (cg)MLST and Bayesian clustering analysis also strongly indicated distribution of two GBS populations in both Thailand and Vietnam. Deep phylogenetic analysis implied by CRISPR array's spacer diversity was able to cluster GBS isolates according to their temporal and geographic origins, though ST7 has varying CRISPR1-spacer profiles when compared to ST283 strains. Based on overall genotypic features, Thai ST283 strains were closely related to the Singaporean ST283 strain causing foodborne illness in humans in 2015, thus, signifying zoonotic potential of this GBS population in the country.

Keywords: Comparative genomics; Fish; Pan-genome; Population genetics; Streptococcus agalactiae; cgMLST.

Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Animals
Fish Diseases / microbiology
Fishes / microbiology
Foodborne Diseases / microbiology
Genomics
Humans
Multilocus Sequence Typing*
Phylogeny*
Serogroup*
Streptococcus agalactiae / genetics*
Streptococcus agalactiae / isolation & purification
Streptococcus agalactiae / pathogenicity
Thailand
Vietnam