耐头孢他啶大肠埃希氏菌产β-内酰胺酶的特性研究  

Study on the Characteristics of Ceftazidime-resistant β-Lactamase Produced by Escherichia Coli

作　　者：李苌清[1] 谢勇恩[1] 凌保东[1] 周岐新[2] 雷军[1] 余娴[1] 

机构地区：[1]四川省川北医学院药物研究所,南充市637007 [2]重庆医科大学药理教研室,重庆市400016

出　　处：《中国药房》2005年第16期1213-1215,共3页China Pharmacy

基　　金：四川省重点科技攻关项目(02SG022-030)

摘　　要：目的:研究耐头孢他啶大肠埃希氏菌产β-内酰胺酶的特性。方法:采用K-B纸片扩散法和等电聚焦对2株耐药大肠埃希氏菌产β-内酰胺酶类型进行初步判断;采用碱裂解法提取质粒并进行PCR扩增测序;β-内酰胺酶经饱和硫酸铵反抽提及SephadexG-75凝胶过滤和DE-52阴离子交换层析法纯化;以SDS-PAGE法测定其分子量及紫外分光光度法测定其酶动力学参数。结果:2株菌产生一种等电点为8.7的超广谱β-内酰胺酶(CTX-M-1V),分子量为29kDa,能水解头孢噻肟和氨曲南,不能水解亚胺培南,对舒巴坦(IC50=94nmol/L)和他唑巴坦(IC50=5nmol/L)敏感。结论:CTX-M-1V为对抑制剂敏感的CTX-M型超广谱-内酰胺酶。OBJECTIVE ： To study the characteristics of ceftazidime - resistant β-lactamase produced by Escherichia coll.METHODS： The types of 2 strains of drug fast β-lactamase produced by Escherichia coil were determined initially by K - B slip diffusion method and ampholine electrophoresis method; The plasmid was extracted by alkaline lysis and the PCR amplification and sequencing were conducted; β-Lactamase was counter- extracted by saturated ammonium sulfate, filtrated by Sephadex G-75 gel and purified by DE- 52 anion exchange chromatography; The molecular weight of which was determined by SDS - PAGE and the enzyme kinetics parameters of β- lactamas were determined by ultraviolet spectrophotometry. RESULTS： The 2 strains produced a super - broad spectrum β- lactamase（CTX - M - 1V） with isoionic point at 8.7 and the molecular weight at 29kDa, which can hydrolyze cefotaxim and aztreonam but imipenem and which was sensitive to sulbactam （IC50= 94nmol/L） and tazobactam（ IC50 = 5nmol/L） . CONCLUSION ： CTX - M - 1V is a CTX - M type super - broad spectrum β-lactamase sensitive to suppressants。

关 键 词：头孢他啶 酶动学 CTX—M型β-内酰胺酶 大肠埃希氏菌 

分 类 号：R969.1[医药卫生—药理学] R978.11[医药卫生—药学]