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Clonal expansion of a virulent Streptococcus suis serotype 9 lineage distinguishable from carriage subpopulations.
- Source :
-
Scientific reports [Sci Rep] 2019 Oct 28; Vol. 9 (1), pp. 15429. Date of Electronic Publication: 2019 Oct 28. - Publication Year :
- 2019
-
Abstract
- Streptococcus suis is a porcine pathogen, causing severe invasive infections. S. suis serotype 9 is increasingly causing disease in Dutch and Chinese pig herds, but it is unknown whether all serotype 9 isolates are equally virulent and markers that can identify virulent strains are not available. Therefore, discrimination between virulent isolates and carriage isolates typically not associated with disease, is currently not possible. We collected tonsillar S. suis isolates from 6 herds not previously diagnosed with S. suis infections, and clinical S. suis isolates of previously diseased pigs. We confirmed the virulence of a virulent type strain and one representative clinical isolate, and the lack of virulence of two carriage isolates, in a pig infection model. Phylogenetic analysis of whole genome sequences of 124 isolates resulted in 10 groups, of which two were almost uniquely populated by clinical isolates. The population structure of S. suis serotype 9 appears highly diverse. However, analysis of the capsule loci sequences showed variation in a single region which fully correlated with a virulent genotype. Transmission electron microscopy suggested differences in capsule thickness between carriage and clinical genotypes. In conclusion, we found that that the S. suis serotype 9 population in the Netherlands is diverse. A distinct virulence-associated lineage was identified and could be discriminated based on the capsule locus sequence. Whilst the difference in virulence cannot be directly attributed to the DNA sequence, the correlation of capsule locus sequence with virulence could be used in the development of diagnostic tests to identify potential virulent S. suis serotype 9 in pigs.
- Subjects :
- Animals
Humans
Swine
DNA, Bacterial genetics
Phylogeny
Serogroup
Streptococcal Infections genetics
Streptococcal Infections microbiology
Streptococcal Infections veterinary
Streptococcus suis genetics
Streptococcus suis pathogenicity
Streptococcus suis ultrastructure
Swine Diseases genetics
Swine Diseases microbiology
Subjects
Details
- Language :
- English
- ISSN :
- 2045-2322
- Volume :
- 9
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Scientific reports
- Publication Type :
- Academic Journal
- Accession number :
- 31659179
- Full Text :
- https://doi.org/10.1038/s41598-019-51576-0