Key Laboratory of Major Diseases in Children and National Key Discipline of Pediatrics (Capital Medical University), Ministry of Education, Beijing Pediatric Research Institute, Beijing Children's Hospital Capital Medical University, Beijing, China.
BMC Infect Dis. 2014 Aug 27;14:467. doi: 10.1186/1471-2334-14-467.
In this study, we defined the population biology of serogroup 6 Streptococcus pneumoniae collected in China and their antibiotic resistance profiles.
The serotypes of 225 S. pneumoniae strains isolated between 1997 and 2011 were identified with the Quellung reaction and serotype-specific PCR. All isolated pneumococci were tested for their sensitivity to 11 kinds of antibiotics with the E-test method or disc diffusion. The sequence types (STs) were analyzed with multilocus sequence typing (MLST).
The frequencies of serotypes and subtypes 6A, 6B-I, 6B-II, 6C, and 6D among the 225 isolates were 46.7% (105/225), 19.6% (44/225), 25.8% (58/225), 6.2% (14/225), and 1.8% (4/225), respectively. Serotype 6E was not found in the serotype 6A isolates, and neither serotype 6F nor 6G was identified in any isolate. MLST analysis revealed 58 STs. The most common STs were ST982 (23.1%), ST90 (14.7%), ST4542 (7.6%), and ST2912 (4.9%). The rates of clonal complex 90 (CC90) and CC386 among the oral-penicillin-nonsusceptible isolates decreased over the years, whereas the rates of CC855 and CC3173 increased. The four CCs had similar penicillin MIC distributions, with a maximum MIC of 2 μg/ml.
This study identified the serotypes/subtypes and CCs/STs of group 6 S. pneumoniae present in China. No salient antibiotic-resistant clones were isolated among the serogroup 6 S. pneumoniae.
本研究旨在定义中国分离的 6 群肺炎链球菌的群体生物学及其抗生素耐药谱。
1997 年至 2011 年间收集的 225 株肺炎链球菌，采用凝聚反应和血清型特异性 PCR 进行血清分型。采用 E 试验法或纸片扩散法检测所有分离的肺炎链球菌对 11 种抗生素的敏感性。采用多位点序列分型（MLST）分析序列型（ST）。
225 株分离株中血清型和亚型 6A、6B-I、6B-II、6C 和 6D 的频率分别为 46.7%（105/225）、19.6%（44/225）、25.8%（58/225）、6.2%（14/225）和 1.8%（4/225）。6A 型分离株中未发现血清型 6E，任何分离株中均未发现血清型 6F 和 6G。MLST 分析显示 58 种 ST。最常见的 ST 为 ST982（23.1%）、ST90（14.7%）、ST4542（7.6%）和 ST2912（4.9%）。口服青霉素不敏感分离株中克隆复合体 90（CC90）和 CC386 的比例逐年下降，而 CC855 和 CC3173 的比例增加。这四个 CC 具有相似的青霉素 MIC 分布，最大 MIC 为 2μg/ml。
本研究确定了中国 6 群肺炎链球菌的血清型/亚型和 CC/ST。未分离到具有明显耐药性的 6 群肺炎链球菌克隆。
