不同emm基因型化脓性链球菌的菌落形态

Distinctive colony morphology categorized by emm genotypes of Streptococcus pyogenes

为探究不同emm基因型的化脓性链球菌的特异性菌落形态,对2019年1—12月从猩红热儿科患者中分离的179株化脓性链球菌进行emm基因测序与分型,观察不同emm基因型的菌落形态。结果表明4种emm基因型(emm12,emm1,emm3和emm4)的菌落特点明显不同,emm12型及亚型菌落为光滑型或粗糙型,直径较小,约0.5 mm。emm1型及亚型均为光滑型,明显区别于emm1的是肉眼可见的菌落大小差异,emm1型菌落较大,大小约为emm12型的2倍。emm3型菌落为所有基因型里最大的,直径3~4 mm,属于黏液型,明显不同于其他3种菌落特点。emm4型大小约0.5 mm,表面光滑或粗糙,溶血不典型。化脓性链球菌的菌落形态有明显的emm基因型特异性,不同emm基因型菌株的菌落特点不同,同一基因型的各亚型菌落特征相同,不同菌落形态可以辅助早期辨别化脓性链球菌的emm基因型。

To categorize the specific colony morphology of Streptococcus pyogenes with different emm types,the colony characteristics of a total of 179 S.pyogenes strains isolated from children patients with scarlet fever from Jan 2019 to Dec 2019 were observed and described.And emm gene sequencing and typing were performed.The distinctive colony morphology was observed in 4 emm types(emm12,emm1,emm3 and emm4).The colonies of emm12 type and its subtypes isolates were smooth or rough in a diameter of 0.5 mm.Compared with emm12,emm1 type and its subtypes were all smooth and presented much bigger colonies than emm12,which were in a diameter of 1 mm as double as emm12.Quite different from others,emm3 type were mucoid with the largest diameter of 3-4 mm.The colonies of emm4 type was about 0.5 mm in diameter with smooth or rough surface,but their beta-hemolytic were slightly different from the colonies of other 3 types.The isolates of S.pyogenes with different emm genotypes owned their special colony morphology.The subtype colonies within the same genotype had the same characteristics.Specific colony morphology could be used for helping to early differentiate emm genotypes of S.pyogenes.