Prevalence of <i>Streptococcus suis</i> Genotypes in Isolates from Porcine Endocarditis in East Japan

Abstract

ABSTRACT. Streptococcus suis is an important pathogen for both swine and humans. In this study, we genotyped 105 S. suis isolates from porcine endocarditis in East Japan on the basis of profiles of capsular serotype-specific, virulence-associated and pilus-associated genes. The most common genotype was cps2J/mrp+/epf−/sly−/sbp2−/sep1−/sgp1+ (76.19%), followed by nt(non-typeable)/mrp+/epf−/sly−/ sbp2−/sep1−/sgp1+ (7.62%) and cps2J/mrp+/epf+/sly+/sbp2+/sep1−/sgp1− (7.62%). The representative isolates of mrp+/epf−/sly−/ sbp2−/sep1−/sgp1+ were classified into ST28 complex, a clonal complex previously referred to as ST27 complex, whereas those of mrp+/epf+/sly+/sbp2+/sep1−/sgp1− were classified into ST1 complex by multilocus sequence typing. Because the majority of human clinical isolates were assigned to ST1 and ST28 complexes, most isolates from porcine endocarditis investigated in this study may have the potential to cause S. suis infection in humans.

Streptococcus suis, an important pig pathogen and emerging zoonotic agent—an update on the worldwide distribution based on serotyping and sequence typing

“…For example, in Japan, ST1 and ST28 strains have been isolated from both species, while ST1 and ST7 strains have been identified for human and pig isolates in mainland China. 53,59,116,128,241,242,248 The situation is similar in Europe where serotype 2 ST1 clonal complex strains are predominately isolated from diseased pigs in Spain, Italy, the Netherlands and the United Kingdom and where most human cases have also been typed as belonging to this complex. 51,62,86,204,240,244 …”

“…246 Regarding Japan, ST1 and ST28 strains isolated from cases of endocarditis in diseased pigs account for 8% and 76% of serotype 2 strains, respectively. 248 …”

“…52,242,244,245,246,248 Nevertheless, other important genetic differences vary between ST1 and ST7 strains including the presence of a 89K pathogenicity island in ST7 strains. 251 These ST1 complex strains interestingly differ from not only the human serotype 2 ST104 strains of Thailand which are sly + mrp - epf - but also from the human serotype 2 ST20 strains recovered in the Netherlands that were epf -.…”

“…244 As for ST25 strains isolated from diseased pigs in North America, these were identified as being SLY-MRP-EF-, while the ST28 isolated from North America, mainland China and Japan were sly - mrp + epf - or SLY-MRP+EF-. 52,246,248 Though currently not as widely used as the above mentioned virulence markers, different pili ( srtB , srtC , srtD , srtF and srtG ) have also been associated with different STs. It was identified that ST1 strains isolated from both diseased pigs and human cases of serotype 2 infections in Japan and Thailand were srtBCD+ and srtF+ but srtG -.…”

Porcine Respiratory Disease Complex and Biofilms

“…Some factors that are encoded by the mrp gene for MRP, epf encodes an EF and sly to cytotoxin (hemolysin) SLY [58]. The cytotoxin SLY (suilysin) seems to protect bacteria against complement-mediated uptake and killing by neutrophils, macrophages and dendritic cells [54].…”