重庆地区肺炎链球菌耐药性和分子流行病学调查

目的调查重庆地区肺炎链球菌在社区获得性感染患者中的分离率及对抗生素的敏感性。方法采集社区获得性感染患者的痰、鼻咽拭子标本,培养、分离和鉴定肺炎链球菌。琼脂二倍稀释法测定肺炎链球菌对11种抗生素的耐药性。通过聚合酶链反应(PCR)扩增肺炎链球菌BOX重复元件对其进行分子流行病学分型。结果680份临床标本中,分离出39株肺炎链球菌,阳性率为5.7%。34株(有5株在保存过程中死亡)肺炎链球菌中有2株对青霉素低度耐药(MIC为0.125mg/L),1株青霉素敏感株对左氧氟沙星耐药(MIC为8mg/L)。肺炎链球菌对大环内酯类抗生素和克林霉素表现出较高的耐药率,且均为高度耐药(MIC≥64mg/L),对所测其他β内酰胺类和万古霉素均呈敏感。盒式PCR显示了较高的分辨率,能快速、可靠地检测菌株间的亲缘关系。35株肺炎链球菌共分为25个型,29个亚型,最多见的为A型图谱(3株),2株青霉素低度耐药株分属不同的型。结论重庆地区分离的临床肺炎链球菌对青霉素耐药率较低,但对大环内酯类抗生素和克林霉素耐药却非常普遍。盒式PCR能快速、可靠地对肺炎链球菌进行分子流行病学分型,重庆地区耐药克隆没有明显的优势株。

Study on drug resistance and molecular epidemiology of Streptococcus pneumoniae isolated in Chongqing

OBJECTIVE: To investigate the prevalence and drug resistance of Streptococcus (S.) pneumoniae in patients infected in communities and molecular epidemiology with BOX-polymerase chain reaction (PCR) in Chongqing areas. METHODS: A total of 680 clinical specimens from sputum and throat/nasal swabs were collected from patients seen from September 2000 to March 2001. Antibiotic susceptibility was determined by agar dilution test. BOX-PCR was used for molecular typing of S. pneumoniae. RESULTS: A total of 39 isolates of S. pneumoniae were collected with the isolation rate of 5.7%. Of the 34 S. pneumoniae strains, two showed low-level resistance to penicillin (MIC 0.125 mg/L), one to levofloxacin, but many to macrolide and clindamycin (nearly 70%). All the strains were susceptible to beta-lactams and vancomycin. BOX-PCR typing demonstrated a high discriminatory potential and easy to be accurately analysed. 35 S. pneumoniae strains (include ATCC49619) were divided into 25 distinct types, representing 29 subtypes with A (n = 3) as the predominant type. 2 penicillin-resistant strains were shown to be different types. CONCLUSION: Penicillin resistant rate of S. pneumoniae was low in Chongqing, but macrolide and clindamycin resistant strains were common while BOX-PCR typing was a suitable technique to type S. pneumoniae. No dominant antibiotic resistant strains were found in Chongqing.