Abstract
Streptococcus suis (S. suis) is an important swine pathogen and an emerging zoonotic agent. Most clinical S. suis strains express capsular polysaccharides (CPS), which can be typed by antisera using the coagglutination test. In this study, 79 S. suis strains recovered from diseased pigs in Canada and which could not be typed using antisera were further characterized by capsular gene typing and sequencing. Four patterns of cps locus were observed: (1) fifteen strains were grouped into previously reported serotypes but presented several mutations in their cps loci, when compared to available data from reference strains; (2) seven strains presented a complete deletion of the cps locus, which would result in an inability to synthesize capsule; (3) forty-seven strains were classified in recently described novel cps loci (NCLs); and (4) ten strains carried novel NCLs not previously described. Different virulence gene profiles (based on the presence of mrp, epf, and/or sly) were observed in these non-serotypeable strains. This study provides further insight in understanding the genetic characteristics of cps loci in non-serotypeable S. suis strains recovered from diseased animals. When using a combination of the previously described 35 serotypes and the complete NCL system, the number of untypeable strains recovered from diseased animals in Canada would be significantly reduced.
Highlights
Streptococcus suis is recognized as one of the most important causes of bacterial disease in post-weaned piglets worldwide, generating important economic losses to the swine industry
Little is known about the distribution and characteristics of the cps loci of potentially virulent non-serotypeable strains recovered from diseased animals
In addition to the traditional 35 serotypes originally described for S. suis, 17 novel cps loci (NCL) have recently been reported in non-serotypeable S. suis strains isolated from healthy animals using high-throughput typing systems and online bioinformatics [22, 23]
Summary
Streptococcus suis is recognized as one of the most important causes of bacterial disease in post-weaned piglets worldwide, generating important economic losses to the swine industry. It is an important emerging zoonotic agent [1,2,3]. 17 novel cps loci (NCLs) were identified from non-serotypeable S. suis and were designated as NCL1 to 16 and serotype Chz [22,23,24]. Little is known about the distribution and characteristics of the cps loci of potentially virulent non-serotypeable strains recovered from diseased animals
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
