2016年北京市昌平区A组乙型溶血性链球菌及相关菌株检测和分析

Detection of group A streptococcus and the relevant strains in Changping District of Beijing,2016

目的对2016年北京市昌平区猩红热病原学监测结果进行分析。方法利用qPCR方法与传统划线分离方法检测病例携带A组乙型溶血性链球菌(GAS)的阳性率,对分离出的GAS进行emm分型。利用16S rRNA和梅里埃VITEK 2 Compact全自动细菌鉴定及药敏分析系统对检测出的非GAS菌株进行鉴定。结果 2016年昌平区采集的132份病例样本中,通过平板划线分离检出GAS 13株(阳性率9.85%),通过qPCR检出GAS 19株(阳性率14.39%)。分离出的GAS的emm型别为emm1和emm12。分离出可培养的非GAS菌种63株,分属于5个不同菌属,共计13种菌种。结论昌平地区GAS的emm型别较为单一,利用qPCR方法比平板划线分离方法更敏感,检测出的阳性GAS率更高。通过分离咽拭子中其他菌株,同时使用16S rRNA方法和梅里埃VITEK 2 Compact全自动细菌鉴定及药敏分析鉴定,两者阳性率有差异,16S rRNA方法更准确。

Objective To analyze the results of pathogenic surveillance of scarlet fever in Changping District of Beijing in 2016. Methods Quantitative polymerase chain reaction （qPCR） assay and plate scribing isolation technique were respectively used to detect the positive rates of carrying group A streptococcus（GAS） of the cases, and the isolated GAS strains were typed by emm genotyping. The identification of the isolated non-GAS strains was conducted using direct 16S rRNA gene sequencing and VITEK2 Compact automatic microbe instrument. Results Among the 132 throat swab specimens collected from the cases in Changping District in 2016, 13 GAS strains were detected by plate scribing and 19 non-GAS strains by qPCR, with the positive rates being 9.85% and 14.39% respectively. The isolated GAS strains were proved to be emm1 and emm12 genotypes. 63 non-GAS strains were isolated, and then identified to belong to 5 genera and 13 species. Conclusions The emm genotypes in Changping District in 2016 were far less diversified. qPCR assay, which has a higher positive detection rate of GAS, is more sensitive than plate scribing isolation method. VITEK2 Compact automatic microbe instrument analysis has obvious limitations in the identification of the non-GAS strains as compared with direct 16S rRNA gene sequencing, and the positive rates detected by the two methods do not match well.