中国北京地区患者分离的 A 组链球菌的分子流行病学和抗菌药物耐药性研究。
Molecular epidemiology and antimicrobial resistance of group a streptococcus recovered from patients in Beijing, China.
机构信息
Department of Dermatology, Children's Hospital Affiliated to Capital Institute of Pediatrics, Beijing, 100020, China.
Department of Clinical Laboratory, Children's Hospital Affiliated to Capital Institute of Pediatrics, Beijing, 100020, China.
出版信息
BMC Infect Dis. 2020 Jul 13;20(1):507. doi: 10.1186/s12879-020-05241-x.
BACKGROUND
Group A streptococcus (GAS) is an important human pathogen responsible for a broad range of infections. Epidemiological surveillance has been crucial to detect changes in the geographical and temporal variation of the disease pattern. The objective of this study was to investigate the molecular epidemiological characteristics and antimicrobial resistance of GAS isolates from patients in Children's Hospital in Beijing.
METHODS
From 2016 to 2017, pharyngeal swab samples were collected from the outpatients in Children's Hospital, Capital Institute of Pediatrics, who were diagnosed with scarlet fever. Antimicrobial susceptibility test was performed according to the distribution of conventional antibiotics and Clinical and Laboratory Standards Institute (CLSI) recommendations. The distribution of the macrolide-resistance genes (ermB, ermA, mefA), emm (M protein-coding gene) typing, and superantigens (SAg) gene profiling were examined by polymerase chain reaction (PCR).
RESULTS
A total of 297 GAS isolates were collected. The susceptibility of the isolates to penicillin, ceftriaxone, and levofloxacin was 100%. The resistance rate to erythromycin and clindamycin was 98.3 and 96.6%, respectively. The dominant emm types were emm12 (65.32%), emm1 (27.61%), emm75 (2.69%), and emm89 (1.35%). Of the 297 isolates, 290 (97.64%) carried the ermB gene, and 5 (1.68%) carried the mefA gene, while none carried the ermA gene. The most common superantigen genes identified from GAS isolates were smeZ (96.97%), speC (92.59%), speG (91.58%), ssa (85.52%), speI (54.55%), speH (52.19%), and speA (34.34%). Isolates with the genotype emm1 possessed speA, speC, speG, speJ, speM, ssa, and smeZ, while emm12 possessed speC, speG, speH, speI, speM, ssa, and smeZ superantigens.
CONCLUSIONS
The prevalent strain of GAS isolates in Beijing has a high resistance rate to macrolides; however, penicillin can still be the preferred antibiotic for treatment. Erythromycin resistance was predominantly mediated by ermB. The common emm types were emm12 and emm1. There was a correlation between emm and the superantigen gene. Thus, long-term monitoring and investigation of the emm types and superantigen genes of GAS prevalence are imperative.
背景
A 组链球菌（GAS）是一种重要的人类病原体，可引起广泛的感染。流行病学监测对于发现疾病模式的地理和时间变化至关重要。本研究的目的是调查北京儿童医院患者中 GAS 分离株的分子流行病学特征和抗菌药物耐药性。
方法
2016 年至 2017 年，从首都儿科研究所附属儿童医院门诊诊断为猩红热的患者中采集咽拭子样本。根据常规抗生素的分布和临床实验室标准协会（CLSI）的建议进行抗菌药物敏感性试验。通过聚合酶链反应（PCR）检测大环内酯类耐药基因（ermB、ermA、mefA）、emm（M 蛋白编码基因）分型和超抗原（SAg）基因谱的分布。
结果
共收集 297 株 GAS 分离株。分离株对青霉素、头孢曲松和左氧氟沙星的敏感性为 100%。对红霉素和克林霉素的耐药率分别为 98.3%和 96.6%。主要的 emm 型为 emm12（65.32%）、emm1（27.61%）、emm75（2.69%）和 emm89（1.35%）。297 株分离株中，290 株（97.64%）携带 ermB 基因，5 株（1.68%）携带 mefA 基因，而无 ermA 基因。从 GAS 分离株中鉴定出最常见的超抗原基因是 smeZ（96.97%）、speC（92.59%）、speG（91.58%）、ssa（85.52%）、speI（54.55%）、speH（52.19%）和 speA（34.34%）。携带 emm1 基因型的分离株携带 speA、speC、speG、speJ、speM、ssa 和 smeZ，而携带 emm12 基因型的分离株携带 speC、speG、speH、speI、speM、ssa 和 smeZ 超抗原。
结论
北京 GAS 分离株的流行株对大环内酯类药物的耐药率较高；然而，青霉素仍可作为首选治疗药物。红霉素耐药主要由 ermB 介导。常见的 emm 型为 emm12 和 emm1。emm 与超抗原基因之间存在相关性。因此，长期监测和调查 GAS 流行的 emm 型和超抗原基因至关重要。
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