Multi locus sequence typing of Streptococcus suis serotype 2 isolated in Sichuan province, 2006-2016

Objective To understand the molecular epidemiological characteristics of Streptococcus suis (S. suis) serotype 2 isolated in Sichuan province from 2006 to 2016 and provide evidence for the prevention and control of human infection with S. suis. Methods Through the polymerase chain reaction (PCR) amplification of the fragments of 7 housekeeping genes and sequencing, multi locus sequence typing (MLST) of 27 strains of S. suis serotype 2 isolated from clinical patients in Sichuan from 2006 to 2016 was conducted. Results MLST typing results showed that the 27 strains could be classified into 2 sequence types, i.e. ST1 and ST7. 19 strains belonged to ST7 and 8 strains belonged to ST1. From 2006 to 2007, the predominant ST was ST7. After 2007, the predominant ST was ST1. Conclusion Sporadic human infection with S. suis occurred in Sichuan in recent years without outbreaks, which might be associated with the change of the ST of the pathogen.