Epidemiology and etiology of a case of human infection with Streptococcus suis in Suzhou, Jiangsu

Objective To understand the epidemiological and etiological characteristics of a case human infection with Streptococcus suis in Suzhou, Jiangsu province, and provide scientific evidence for the prevention and control of human infection with S. suis．

Methods A field survey was conducted to identify the infection route and source of the case, and the biochemical identification of the pathogenic strains isolated from the samples from the case and the nasal swabs and tonsils of 80 pigs were conducted with VITEK2 compact and PCR was used for species specific gene (16S rRNA) and 4 virulence genes (cps2J, sly, ef and mrp) detections.

Results The epidemiological survey indicated that the case had cut on his hand and might be infected with S. suis during the process of pork washing. The PCR results indicated that the strain isolated from the case′s blood sample was positive for species specific gene (16S rRNA) and 4 virulence genes (cps2J, sly, ef and mrp). The biochemical identification results showed that the two strains isolated from pig′s nasal swabs were positive for S. suis serotype 2, the detection result of sly was positive.

Conclusion The case might be infected with virulent S. suis by accident. The low virulence of the S. suis serotype 2 in healthy pigs poses no threat to human health; Comprehensive measures, including intensified quarantine, surveillance, health education and self-protection, should be taken for high risk group to control and prevent human infection with S. suis.