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Identification of six novel capsular polysaccharide loci ( NCL ) from Streptococcus suis multidrug resistant non‐typeable strains and the pathogenic characteristic of strains carrying new NCL s
Author(s) -
Huang Jinhu,
Liu Xi,
Chen Hao,
Chen Li,
Gao Xueping,
Pan Zihao,
Wang Jian,
Lu Chengping,
Yao Huochun,
Wang Liping,
Wu Zongfu
Publication year - 2019
Publication title -
transboundary and emerging diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.392
H-Index - 63
eISSN - 1865-1682
pISSN - 1865-1674
DOI - 10.1111/tbed.13123
Subject(s) - streptococcus suis , biology , microbiology and biotechnology , serotype , virulence , virology , tetracycline , antibiotics , genetics , gene
Streptococcus suis is a major swine pathogen and an important zoonotic agent worldwide. At least nine serotypes can infect human so far. Although 29 serotypes (1–19, 21, 23–25, 27–31 and 1/2) strains are considered as authentic S. suis , a novel variant serotype Chz and strains carrying 20 novel capsular polysaccharide loci ( NCL ) have been identified recently. However, information about pathogenic and antimicrobial resistance characteristics of strains carrying NCL s is still unavailable. In this study, we identified six new NCL s (designated as NCL 21‐26) from 35 non‐typeable S. suis strains by agglutination tests and whole genome sequencing analysis. Further analysis of the genetic context of NCL 25 and NCL 26 showed a mosaic structure of the capsular polysaccharide loci. NCL 25 exhibited considerable similarity to that of serotypes 10 and 11, and NCL 26 shared similarity to that of serotype 9 and NCL 4. Antimicrobial susceptibility testing demonstrated that strains carrying NCL 21‐26 were all resistant to clindamycin, lincomycin, erythromycin, tilmicosin and tetracycline. Animal infection experiments showed that the virulence of NCL 26 strain NJ 1112 isolated from a disease pig was similar to that of S. suis serotype 2 virulent strain SC 070731 in both zebrafish and mouse infection models, highlighting the necessity for surveillance of strains belonging to NCL 26. We also developed a multiplex PCR assay to detect NCL 21‐26 strains. Our findings expand the views of genetic diversity of S. suis capsular polysaccharide loci and S. suis pathogenic characteristic.