Department of Dermatology, Children's Hospital Affiliated to Capital Institute of Pediatrics, Beijing, China.
Department of Clinical Laboratory, Children's Hospital Affiliated to Capital Institute of Pediatrics, Beijing, China.
Eur J Clin Microbiol Infect Dis. 2020 Dec;39(12):2361-2371. doi: 10.1007/s10096-020-03987-5. Epub 2020 Jul 16.
Our study aimed to investigate the epidemiological and molecular characteristics of isolates collected from Group A Streptococcus (GAS) infections in children in Beijing China during the year 2019. Emm typing, superantigens, and erythromycin resistance genotypes were determined by PCR. Antimicrobial susceptibility testing was performed as recommended by Clinical Laboratory Standards Institute (CLSI). A total of 271 GAS isolates were collected. Thirteen different emm types, including 31 subtypes, were identified. The most prevalent emm types were emm12 (52.77%), emm1 (36.9%), emm3.1 (2.95%), and emm75.0 (2.95%). Two variant subtypes, STC36.0 and STG840.2, were identified. There was no difference in the portion of emm12 and emm1 isolates in scarlet fever, impetigo, and psoriasis. The majority of superantigens detected were smeZ (94.46%), speC (91.14%), and ssa (74.91%), followed by speH (56.46%), speI (45.76%), speJ (36.9%), and speA (34.32%). More scarlet fever isolates harbored speA (35.6%) and speJ (38.4%), more psoriasis isolates harbored speI (57.9%), and more impetigo isolates harbored ssa (89.7%). Isolates were universally susceptible to penicillin and resistant to erythromycin (94.83%). Moreover, 89.67% erythromycin resistance isolates harbored the ermB gene. The erythromycin resistance rate of the isolates from the three diseases was different. Scarlet fever is the common streptococcal infectious disease in dermatology. Emm12 and emm1 were the most prevalent emm types. The most prevalent superantigens detected were smeZ, spec, and ssa. There is association between diversity of superantigens and disease manifestation. Hence, continuous surveillance of GAS molecular epidemiological characterizations in different diseases is needed.
我们的研究旨在调查 2019 年中国北京 A 组链球菌（GAS）感染患儿分离株的流行病学和分子特征。通过 PCR 确定 Emm 分型、超抗原和红霉素耐药基因型。按照临床实验室标准化研究所（CLSI）的建议进行抗菌药物敏感性测试。共收集 271 株 GAS 分离株。鉴定出 13 种不同的 Emm 型，包括 31 个亚型。最常见的 Emm 型是 emm12（52.77%）、emm1（36.9%）、emm3.1（2.95%）和 emm75.0（2.95%）。还鉴定出 2 种变异亚型 STC36.0 和 STG840.2。猩红热、脓疱疮和银屑病中 emm12 和 emm1 分离株的比例无差异。检测到的大多数超抗原是 smeZ（94.46%）、speC（91.14%）和 ssa（74.91%），其次是 speH（56.46%）、speI（45.76%）、speJ（36.9%）和 speA（34.32%）。更多的猩红热分离株携带 speA（35.6%）和 speJ（38.4%），更多的银屑病分离株携带 speI（57.9%），更多的脓疱疮分离株携带 ssa（89.7%）。分离株对青霉素普遍敏感，对红霉素耐药（94.83%）。此外，89.67%的红霉素耐药分离株携带 ermB 基因。三种疾病的红霉素耐药率不同。猩红热是皮肤科常见的链球菌感染性疾病。Emm12 和 emm1 是最常见的 Emm 型。检测到的最常见的超抗原是 smeZ、spec 和 ssa。超抗原的多样性与疾病表现有关。因此，需要对不同疾病的 GAS 分子流行病学特征进行持续监测。
