2014—2022年湖南省病人来源猪链球菌2型鉴定及毒力基因分析

Identification and virulence genes of Streptococcus suis serotype 2 isolated from patients in Hunan Province,2014-2022

目的了解2014—2022年湖南省人感染猪链球菌病病人分离株型别分布与毒力基因携带情况,为人感染猪链球菌病的防控提供依据。方法收集2014—2022年湖南省人感染猪链球菌病临床分离株,通过传统生化反应和聚合酶链反应(polymerase chain reaction,PCR)检测猪链球菌种特异性基因16S rRNA,同时用PCR对2型血清型鉴定基因(兼荚膜多糖毒力基因)cps2J和7种毒力基因进行扩增,用毛细管电泳检测扩增产物,分析病人来源猪链球菌的型别与毒力基因携带情况。结果2014—2022年湖南省38株人感染猪链球菌病临床分离株中,1株为羊链球菌,32株为猪链球菌2型,5株生化鉴定为2型的菌株经分子分型鉴定为猪链球菌其他型别。32株猪链球菌2型菌株中,46.88%的菌株携带全部8种毒力基因,40.63%的菌株携带除mrp外的7种毒力基因。携带cps2J、fbps、ef、gdh、orf2、gapdh 6种毒力基因与携带cps2J、sly、gdh、orf2、gapdh 5种毒力基因的菌株均占3.13%,6.25%的菌株携带cps2J、gdh、orf2、gapdh 4种毒力基因。mrp毒力基因阴性菌株中58.82%(10/17)引起脑膜炎和中毒性休克综合征。结论2014—2022年湖南地区猪链球菌病人来源分离株以多毒力基因2型菌株为主,其毒力机制复杂,对人危害大,需引起持续关注。16S rRNA检测与分子分型能弥补猪链球菌生化鉴定的不足。

To determine the serotype distribution and virulence gene carrying status of isolates from patients infected with Streptococcus suis disease in Hunan Province from 2014 to 2022,and to provide a basis for prevention and control of human infected with Streptococcus suis disease.Methods We collected clinical isolates from patients with Streptococcus suis disease in Hunan Province from 2014 to 2022.Streptococcus suis species-specific gene 16S rRNA was detected by traditional biochemical reaction and polymerase chain reaction(PCR).At the same time,PCR was used to amplify cps2J gene of Streptococcus suis serotype 2 and 7 kinds of virulence genes,and capillary electrophoresis was employed to detect the amplified products.Serotype and virulence gene carrying status of Streptococcus suis isolated from the patients were analyzed.Results Among 38 strains of clinical isolates from patients with Streptococcus suis disease in Hunan Province during 2014-2022,1 isolate strain was identified as Streptococcus ovis,and 32 isolate strains were identified as Streptococcus suis serotype 2.5 isolate strains identified as Streptococcus suis type 2 by biochemical reaction were identified as other serotypes of Streptococcus suis by molecular typing.Among the 32 strains of Streptococcus suis serotype 2,46.88% of the strains carried all 8 virulence genes,and 40.63% of the strains carried 7 virulence genes except mrp.Strains carrying cps2J,fbps,ef,gdh,orf2 and gapdh virulence genes accounted for 3.13%,and those carrying cps2J,sly,gdh,orf2 and gapdh virulence genes for 3.13% too.6.25% of the strains carried cps2J,gdh,orf2 and gapdh virulence genes.58.82%(10/17)of mrp-strains caused meningitis and toxic shock syndrome.Conclusion Streptococcus suis serotype 2 strains with multispecies virulence genes were the main isolates from patients with Streptococcus suis disease in Hunan in 2014-2022.The virulence mechanism of Streptococcus suis serotype 2 is complex,and it is harmful to human beings,which needs continuous attention.16S rRNA detection and molecular typing can make up for the deficiency of biochemical identification of Streptococcus suis.