广东省猪链球菌2型菌株毒力基因及分子分型分析

目的 掌握广东地区猪链球菌2型菌株毒力因子及分子分型情况,为诊断、治疗和制定防控措施提供科学依据。方法 选取荚膜多糖(cps2J)、溶菌酶释放蛋白(mrp)、溶血素(sly)、谷氨酸脱氢酶(gdh)、胞外因子(ef)等5个猪链球菌2 型主要毒力基因,分别设计引物对分离自病人、病猪的22株猪链球菌2 型菌株进行PCR检测,并对菌株进行MLST分型分析。结果 22株菌分为5种毒力基因型,其中cps2J+/mrp+/sly+/gdh+/ef+型别为病人及病猪菌株所共有,cps2J+/mrp+/sly-/gdh-/ef+、cps2J+/mrp+/sly-/gdh+/ef+为病人菌株所特有,cps2J+/mrp-/sly+/gdh+/ef+、cps2J+/mrp-/sly-/gdh+/ef-为病猪菌株所特有;MLST分型结果显示,22株分为ST1、ST7和ST28三个型别,其中ST1、ST7型为病人和病猪菌株所共有,均同属于ST1克隆复合物,ST28型为病猪所特有。结论 广东地区病人、病猪的猪链球菌2 型菌株毒力基因型及MLST分子分型均呈现多样化,且部分型别为两者所共有,为阐明猪传染给人提供了直接的证据。

Analysis on the main virulence genes and molecular typing of Streptococcus suis type 2 in Guangdong Province

In this study, we aims to grasp virulence factors and molecular typing of Streptococcus suis type 2 strains in Guangdong, providing the scientific basis for the diagnosis, treatment, and prevention and control measures. Totally 5 virulence genes, including the capsular polysaccharides gene (cps2J), the muramidate released protein gene (mrp), the suilysin gene (sly), and the glutamate dehydrogenase gene (gdh), were detected by PCR amplification, and MLST classification analysis on the stains was conducted. Strains of 22 were divided into 5 kinds of virulence gene type, of which the cps2J+/mrp+/sly+/gdh+/ef+ type was common to patients and sick pig strains, cps2J+/mrp+/sly-/gdh-/ef+ and cps2J+/mrp+/sly-/gdh+/ef+ specific to patients strains, and cps2J+/mrp-/sly+/gdh+/ef+ and cps2J+/mrp-/sly-/gdh+/ef- unique to sick pig strains. MLST typing results showed that 22 strains included ST1, ST7 and ST28 types, of which ST1 and ST7 were common to the strains from patients and sick pigs, both of the members in the ST1 clone complexes, and ST28 were unique to sick pigs. In Guangdong, the virulence genes and MLST molecular typing of Streptococcus suis type 2 strains from patients and sick pigs of the strains present diversified, and part of the types were common to both patients and sick pigs, providing direct evidence for clarifying the transmission of pig to human.