Department of Microbiology, Shanghai Municipal Center for Disease Control and Prevention, Shanghai, PR China; Department of Microbiology, Shanghai Institutes of Preventive Medicine, Shanghai, PR China.
Department of Infectious Diseases, Children's Hospital of Fudan University, Shanghai, PR China.
Int J Infect Dis. 2020 Sep;98:305-314. doi: 10.1016/j.ijid.2020.06.053. Epub 2020 Jun 17.
Scarlet fever epidemics caused by group A Streptococcus (GAS) have been ongoing in China since 2011. However, limited data are available on the dynamic molecular characterizations of the epidemic strains.
Epidemiological data of scarlet fever in Shanghai were obtained from the National Notifiable Infectious Disease Surveillance System. Throat swabs of patients with scarlet fever and asymptomatic school-age children were cultured. Illumina sequencing was performed on 39emm1 isolates.
The annual incidence of scarlet fever was 7.5-19.4/100,000 persons in Shanghai during 2011-2015, with an average GAS carriage rate being 7.6% in school-age children. The proportion ofemm1 GAS strains increased from 3.8% in 2011 to 48.6% in 2014; they harbored a superantigen profile similar to emm12 isolates, except for the speA gene. Two predominant clones, SH001-emm12, and SH002-emm1, circulated in 66.9% of scarlet fever cases and 44.8% of carriers. Genomic analysis showed emm1 isolates throughout China constituted distinct clades, enriched by the presence of mobile genetic elements carrying the multidrug-resistant determinants ermB and tetM and virulence genes speA, speC, and spd1.
A significant increase in the proportion ofemm1 strains occurred in the GAS population, causing scarlet fever in China. Ongoing surveillance is warranted to monitor the dynamic changes of GAS clones.
自 2011 年以来，中国一直存在 A 组链球菌（GAS）引起的猩红热流行。然而，关于流行菌株的动态分子特征的可用数据有限。
从国家法定传染病监测系统获取上海猩红热的流行病学数据。采集猩红热患者和无症状学龄儿童的咽拭子进行培养。对 39 株 emm1 分离株进行 Illumina 测序。
2011-2015 年期间，上海猩红热的年发病率为 7.5-19.4/100000 人，学龄儿童 GAS 携带率平均为 7.6%。emm1 GAS 菌株的比例从 2011 年的 3.8%增加到 2014 年的 48.6%；它们携带的超抗原谱与 emm12 分离株相似，除了 speA 基因。两种主要克隆株 SH001-emm12 和 SH002-emm1 在 66.9%的猩红热病例和 44.8%的携带菌株中循环。基因组分析表明，中国各地的 emm1 分离株构成了不同的分支，这些分支中富集了携带多药耐药决定簇 ermB 和 tetM 以及毒力基因 speA、speC 和 spd1 的可移动遗传元件。
emm1 菌株在 GAS 人群中的比例显著增加，导致中国猩红热的发生。需要进行持续监测以监测 GAS 克隆的动态变化。
