Chloromycetin resistance of clinically isolated E coli is conversed by using EGS technique to repress the Chloromycetin acetyl transferase
Chloromycetin resistance of clinically isolated E coli is conversed by using EGS technique to repress the Chloromycetin acetyl transferase作者机构：Department of Infectious Diseases Tongji Hospital Tongji JVledical CollegeHuazhong University of Science and Technology Wuhan 430030Hubei Province China School of Pharmacy Tongji Medical CollegeHuazhong University of Science and Technology Wuhan 430030Hubei Province China Laboratory of Immunology Wuhan Bioproduct Institute of Ministry of Public Health Wuhan 430060 Hubei Province China
出 版 物：《World Journal of Gastroenterology》 (世界胃肠病学杂志（英文版）)
年 卷 期：2005年第11卷第46期
页 面：7368-7373页
核心收录：
学科分类：1007[医学-药学(可授医学、理学学位)] 100705[医学-微生物与生化药学] 1001[医学-基础医学(可授医学、理学学位)] 100103[医学-病原生物学] 10[医学]
基 金：Supported by the National Natural Science Foundation of China No. 39570846
主 题：External guide sequence Drug-resistant bacteria Conversion of drug resistance
摘 要：AIM： To explore the possibility of repression of chloromycetin （Cm） acyl transferase by using external guided sequence （EGS） in order to converse the clinical E coli isolates from Cm- resistant to Cm- sensitive. METHODS： EGS directed against chloromycetin acetyl transferase gene （cat） was cloned to vector pEGFP-C1 which contains the kanamycin （Kin） resistance gene. The recombinant plasmid pEGFP-C1＋EGScatl＋cat2 was constructed and the blank vector without EGS fragment was used as control plasmids. By using the CaCl2 transformation method, the recombinant plasmids were introduced into the clinically isolated Cm resistant but Km sensitive E coli strains. Transformants were screened on LB agar plates containing Kin. Extraction of plasmids and PCR were applied to identify the positive clones. The growth curve of EGS transformed bacteria cultured in broth with Cm resistance was determined by using spectrophotometer at A600. Drug sensitivity was tested in solid culture containing Cm by using KB method. RESULTS： Transformation studies were carried out on 16 clinically isolated Cm-resistant （250 μg/mL of Cm） E colistrains by using pEGFP-C1-EGScatlcat2 recombinant plasmid. Transformants were screened on LB-agar plates containing Km after the transformation using EGS. Of the 16 tested strains, 4 strains were transformed successfully. Transformants with EGS plasmid showed growth inhibition when grown in liquid broth culture containing 200 μg/mL of Cm. In drug sensitivity test, these strains were sensitive to Cm on LB-agar plates containing 200 μg/mL of Cm. Extraction of plasmids and PCR amplification showed the existence of EGS plasmids in these four transformed strains. These results indicated that the Cat of the four clinical isolates had been suppressed and the four strains were converted to Cm sensitive ones. CONCLUSION： The EGS directed against Cat is able to inhibit the expression of Cat, and hence convert Cm- resistant bacteria to Cm-sensitive ones. Thus, the EGS h
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