Identification and virulence genes of Streptococcus suis serotype 2 isolated from patients in Hunan Province,2014-2022
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.
Streptococcus suispolymerase chain reactionvirulence genehuman infection with Streptococcus suismolecular typing
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