摘要
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 investigate the genetic structure of serotype 14 Streptococcus pneumoniae (S.pneumoniae) isolated from children with acute respiratory infections during two periods: from 1997 to 2006, and in 2010, in Beijing Children's Hospital Methods The serotype 14 isolates were characterized by antibiotic susceptibility using E-test and disk diffusion method. The macrolide resistance genes ermB and mefA were tested by PCR. The dihydrofolate reduc- tase (dhfr) gene sequence and muhilocus sequence typing (MLST) were determined. Results The percentage of sero- type 14 in S.pneumoniae isolates increased from 0% in 1997-1999 to 9.3% in 2010. All the 61 serotype 14 S.pneumoni- ae isolates were susceptible to penicillin, amoxicillin-clavulanic acid and cefiriaxone, but their MICS0 and MICg0 in- creased in this period. The non-susceptibility rate to cefuroxime increased from 0% in 1997-1999 to 84.6% in 2010. All the isolates were resistant to erythromycin and carried the ermB gene, and 4 isolates (6.6%) carried mefA gene addition- ally. All sulfamethoxazole-trimethoprim resistant isolates contained the Ilel00-Leu mutation. Totally 11 STs were identi- fied, among which ST875 was the most prevalent one (52.5%), followed by ST876 (21.3%). From 1997 to 2010, thepercentage of CC876 among serotype 14 S.pneumoniae isolates increased from 0% in 1997-1999 to 92.3% in 2010, whereas CC875 decreased from 100% to 0%. CC876 showed higher resistance to β-1actam antibiotics than CC875. Conclusion The percentage of serotype 14 in S.pnenmoniae isolates increased from 1997 to 2010 in Beijing with increasing resistance to β-laetam antibiot-ics, which is assicated with the spread of CC876 with higher resistance under the antibiotics slective pressure.
出处
《中国实用儿科杂志》
CSCD
北大核心
2014年第3期199-204,共6页
Chinese Journal of Practical Pediatrics
基金
国家自然科学基金(81378153)
科技部创新药物研究开发技术平台建设项目(2011ZX09302)
北京市科委行业定额经费自主项目(2013-bjsekyjs-3)
关键词
肺炎链球菌
血清型
抗生素敏感性
分子流行病学
Streptococcus pneumoniae
serotype
antimicrobial resistance
molecular epidemiology