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目的了解14型肺炎链球菌的抗生素敏感性及分子流行病学特征。方法以北京儿童医院1997—2010年分离自儿童鼻咽拭子的14型肺炎链球菌分离株为研究对象,采用E-test法和纸片扩散法检测菌株对11种抗生素的敏感性,采用多位点序列分型(MLST)确定菌株序列型(ST),eBURST软件分析确定克隆群(CC)。聚合酶链式反应(PCR)检测红霉素耐药基因ermB和mefA,扩增并测序二氢叶酸还原酶基因dhfr。结果肺炎链球菌分离株中14型所占比例在监测期间升高,从1997—1999年的3.9%升高至2010年的9.3%。61株14型肺炎链球菌均对青霉素、阿莫西林-克拉维酸、头孢曲松敏感,但MIC50、MIC90和最大MIC值在监测期间升高。头孢呋辛不敏感率从1997—1999年的0上升至2010年的84.6%。61株均对红霉素耐药,携带ermB基因,4株(6.6%)同时携带mefA基因。36株磺胺耐药菌株均携带Ile100-Leu变异。MLST共分出11种STs,ST875最常见(32株,占52.5%),其次是ST876(13株,占21.3%)。从1997到2010年,CC875的构成比下降(从1997—1999年的100%降为2010年的0),CC876的构成比升高(从1997—1999年的0升至2010年的92.3%)。CC876对β-内酰胺类抗生素耐药性明显高于CC875。结论 1997年到2010年肺炎链球菌中14型的构成比升高,14型菌株对β-内酰胺类抗生素耐药性增强,与具有高β-内酰胺类抗生素耐药性的克隆群CC876的播散有关。
Objective To understand the antibiotic susceptibility and molecular epidemiological characteristics of Streptococcus pneumonia 14. Methods The 14 Streptococcus pneumoniae isolates isolated from children’s nasopharyngeal swabs from 1997 to 2010 in Beijing Children’s Hospital were selected as the research objects. The sensitivity of the strains to 11 antibiotics was tested by E-test and disk diffusion method. Site sequence typing (MLST) confirmed strain sequence (ST) and eBURST software analysis identified clonal group (CC). Erythromycin resistance genes ermB and mefA were detected by polymerase chain reaction (PCR) and dihydrofolate reductase gene dhfr was amplified and sequenced. Results The proportion of type 14 in S. pneumoniae isolates increased during the monitoring period from 3.9% in 1997-1999 to 9.3% in 2010. 61 strains of Streptococcus pneumoniae 14 were sensitive to penicillin, amoxicillin-clavulanic acid and ceftriaxone, but MIC50, MIC90 and maximum MIC value increased during the monitoring period. The insensitivity rate of cefuroxime rose from 0 in 1997-1999 to 84.6% in 2010. 61 strains were resistant to erythromycin, carrying ermB gene and 4 strains (6.6%) carrying mefA gene simultaneously. 36 strains of sulfa resistant strains carry Ile100-Leu mutation. MLST was divided into 11 kinds of STs, ST875 the most common (32 strains, accounting for 52.5%), followed by ST876 (13 strains, accounting for 21.3%). From 1997 to 2010, the composition ratio of CC875 decreased (from 100% in 1997-1999 to 0 in 2010), and the composition ratio of CC876 increased (from 0 in 1997-1999 to 92.3% in 2010) . CC876 resistance to β-lactam antibiotics was significantly higher than CC875. Conclusion The constituent ratio of type 14 in Streptococcus pneumoniae increased from 1997 to 2010, and the resistance of type 14 strain to β-lactam antibiotics was enhanced. Compared with the clone group CC876 with high β-lactam antibiotic resistance Dissemination related.