Lack of mitogenic activity of speG- and speGdys-positive Streptococcus dysgalactiae subspecies equisimilis isolates from patients with invasive infections

摘要: In recent years, Streptococcus dysgalactiae subspecies equisimilis has been isolated with an increasing frequency as the cause of invasive streptococcal diseases. For 46 S. isolates from infections and four superficial infections, presence emm/emmL genes encoding various different superantigens was determined by polymerase chain reaction (PCR). Subsequently, PCR products were identified DNA sequencing, expression mRNA superantigen assessed reverse transcriptase-PCR. The mitogenic activity [3H]thymidine incorporation into human lymphocytes compared that agalactiae pyogenes. All studied harbored gene. Only in six speG detected PCR, two which further speGdys sequencing product. None any speA, speB, speC, speF, speH, speI, speJ, speK, speL, speM, smeZ, or ssa contrast to pyogenes, no mRNA, respectively, transcriptase-PCR assay for speG- speGdys-positive isolates. Moreover, revealed very low activity, while pyogenes a powerful inducer proliferative responses. These findings support hypothesis pathogenicity may be associated part genes, suggest severity is not mediated superantigen-induced mitogenicity.