耐氨苄西林肠球菌β-内酰胺酶及基因的检测  

Detection of β-Lactamase and blaZ Gene of Ampicillin-resistant Enterococcus

作　　者：许淑珍[1] 童乐艳[1] 于艳华[1] 

机构地区：[1]首都医科大学附属北京友谊医院临床检验中心,北京100050

出　　处：《中华医院感染学杂志》2008年第7期928-930,共3页Chinese Journal of Nosocomiology

摘　　要：目的采用不同方法检测耐氨苄西林肠球菌的β-内酰胺酶,以提高β-内酰胺酶的检出率,指导临床选药治疗。方法根据美国CLSI指南做药敏试验,用头孢硝噻吩纸片法和试管法检测β-内酰胺酶及PCR检测blaZ基因,单链构象多态性(SSCP)检测pbp4的基因突变。结果耐氨苄西林屎肠球菌和粪肠球菌对青霉素、高浓度庆大霉素、高浓度链霉素、左氧氟沙星、红霉素、四环素、氯霉素、利福平的耐药率分别为100%、100%;86%、76%;46%、44%;84%、74%;100%、94%;54%、58%;42%、36%;62%、58%,未发现耐万古霉素菌株;50株粪肠球菌纸片法β-内酰胺酶阳性率为8%,试管法26%;PCR检测blaZ基因的阳性率为88%;50株屎肠球菌纸片法未检测出阳性菌株,试管法检出的阳性率为2%;PCR检测blaZ基因阳性率为22%;50株粪肠球菌经SSCP分析及测序未发现有义突变位点。结论由β-内酰胺酶介导的耐氨苄西林粪肠球菌检出率明显高于屎肠球菌,PCR法优于头孢硝噻吩法,头孢硝噻吩法中试管法较纸片法检出阳性率高。OBJECTIVE To detect β-lactamase of ampicillin-resistant Enterococcus in order to choose drugs for clinical treatment. METHODS According to CLSI＇s guideline, antimicrobial susceptibility tests were performed： to detect β-lactamase with nitrocefin, to detect blaZ by PCR and to detect mutation of pbp4 by single-strand conformation polymorphism （SSCP）. RESULTS The resistant rates of E. faecium and E. faecalis to ampicillin, penicillin, high level gentamicin, high level streptomycin, levofloxacin, erythromycin, tetracycline, and chloramphenicolwere100%, 100%;86M, 76%;46%, 44%;84%, 74%;100%, 94%;54%, 58%;and 42%, 36 % ; to rifampicin 62 %, 58 % ; and to vancomycin both 0%, respectively. The positive rate of β-lactamase in 50 E. faecalis strains with paper disk method and test tube method was 8% and 26% ; and that of blaZ by PCR was 88%.. But in 50 E. faeciurn strains the results were 0% and 2%, respectively. There was no significant mutation by SSCP and sequencing in E. faecalis. CONCLUSIONS The positive rate to β-lactamase in E. faecalis is markedly higher than in E. faecium. The method of PCR is better than that of nitrocefin. The positive rate of test tube method is higher than paper disk method with nitrocefin.

关 键 词：肠球菌属 氨苄西林 Β-内酰胺酶 基因 

分 类 号：R378.1[医药卫生—病原生物学]