Presence of Human-Associated Clade Marker Gene HAC-G19 in Streptococcus suis Isolated From Humans and Swine.

Abstract

Streptococcus suis is a zoonotic pathogen contributing to human and pig infections. Effective techniques to distinguish pathogenic from non-pathogenic pathotypes of S. suis is required for public health surveillance. Herein, we developed and evaluated a PCR approach detecting the human-associated clade (HAC)-G19 marker gene to identify the pathogenic pathotype of S. suis. The study was conducted on 599 human strains, 82 diseased-pig strains, and 299 clinically healthy pig strains. PCR analysis revealed that 98.8% and 75.6% were HAC-G19 positive in human and diseased-pig strains, whereas 67.6% of healthy pig strains were negative for the HAC-G19 gene. Statistical analysis revealed that the HAC-G19 gene was more significantly present in diseased-associated isolates than in healthy pig isolates (p-value < 0.001), being with OR of 50.4 (95% CI = 32.1-79.5). Diagnostic accuracy was 87.4% (95% CI = 85.1-89.49%) with sensitivity and specificity were 96.1% (95% CI = 94.3-97.4%) and 67.6% (95% CI = 61.9-72.8%), respectively. This demonstrated that PCR of HAC-G19 has a potential to predict pathogenic pathotype for S. suis.