ABSTRACT
Streptococcus (S.) suis is a globally important swine pathogen, which comprises certain zoonotic serotypes. In this study, a detailed characterization of 88 porcine S. suis isolates was performed by analyzing capsular (cps) types, multilocus sequence typing (MLST) and investigation of the minimum core genome (MCG). In order to focus on the virulence potential of presumable invasive disease-associated S. suis isolates, virulence-associated gene profiles were assessed followed by screening a chosen subset of S. suis strains with a molecular pathotyping tool. Results showed a high genetic variability within this strain collection. In total, seventeen cps types were identified with a predominance of cps type 9 (15.9%) and 6 (14.8%). MLST revealed 48 sequence types (STs) including 41 novel ones. The population structure of S. suis was heterogenous and isolates belonged to eight different clonal complexes (CCs) including CC28 (9.1%), CC1109 (8%), CC13/149 (6.8%), CC1237 (5.7%), CC1 (3.4%), CC17 (3.4%), CC87 (2.3%), and CC1112 (1.1%), whereas a significant portion of isolates (60.2%) could not be assigned to any described CCs. Virulence-associated markers, namely extracellular protein factor (epf), muramidase-released protein (mrp), and suilysin (sly), showed a link with STs rather than with cps types. With this study an expanded knowledge about the population structure and the genetic diversity of S. suis could be achieved, which helps to contribute to an optimal public health surveillance system by promoting a focus on strains with an increased virulence and zoonotic potential.
Subject(s)
Streptococcal Infections/veterinary , Streptococcus suis/physiology , Streptococcus suis/pathogenicity , Swine Diseases/microbiology , Animals , Multilocus Sequence Typing/veterinary , Prevalence , Streptococcal Infections/epidemiology , Streptococcal Infections/microbiology , Streptococcus suis/genetics , Sus scrofa , Swine , Swine Diseases/epidemiology , Switzerland/epidemiology , Virulence/geneticsABSTRACT
This rapid high resolution melting (HRM) assay allows distinguishing between Streptococcus suis serotype pairs 2 and 1/2 as well as 1 and 14, respectively, based on a single-nucleotide polymorphism within capsular polysaccharide synthesis gene cluster K. This assay is easy to implement and identifies potential zoonotic serotypes.
Subject(s)
Bacterial Capsules/genetics , Molecular Typing/methods , Polysaccharides, Bacterial/genetics , Serotyping/methods , Streptococcus suis/classification , Streptococcus suis/genetics , Animals , Genome, Bacterial/genetics , Humans , Polymorphism, Single Nucleotide/genetics , Serogroup , Streptococcal Infections/microbiology , Swine , Swine Diseases/microbiology , Whole Genome Sequencing/methodsABSTRACT
Here we report the whole-genome sequences of 15 clinical Streptococcus suis strains isolated from pigs in Switzerland. Although they originated from the same host and geographic origin, the strains showed a large amount of diversity.