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中国防痨杂志 ›› 2012, Vol. 34 ›› Issue (10): 670-675.

• 论著 • 上一篇    下一篇

结核分枝杆菌利福平依赖性的初步研究

金海霞 付雷 王彬 郑梅琴 陆宇   

  1. 101149  北京市结核病胸部肿瘤研究所药物研究室
  • 收稿日期:2012-04-27 出版日期:2012-10-10 发布日期:2013-01-08
  • 通信作者: 陆宇 E-mail:luyu4876@hotmail.com

Study on the rifampicin-dependent characteristics of Mycobacterium tuberculosis clinical isolate

JIN Hai-xia, FU Lei, WANG Bin, ZHENG Mei-qin, LU Yu   

  1. Pharmacology Research Lab, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China
  • Received:2012-04-27 Online:2012-10-10 Published:2013-01-08
  • Contact: LU Yu E-mail:luyu4876@hotmail.com

摘要: 目的  从耐利福平(RFP)结核分枝杆菌临床分离株中筛选RFP依赖的菌株,并在小鼠模型中验证RFP依赖现象,同时分析RFP依赖菌株的特征。  方法  采用7H11培养基绝对浓度法对46例临床分离菌株进行RFP依赖菌株筛选。以筛选得到的体外具有典型的RFP依赖现象的05116菌株建立气溶胶感染的小鼠模型,小鼠按照给药的种类和给药单位剂量分成对照组0.5%羧甲基纤维素钠(carboxymethyl cellulose sodium,CMC)、10 mg/kg  Rfb(Rfb10)组、10 mg/kg RFP(RFP10)组、20 mg/kgRFP(RFP20)组,每组各10只,观察给药4、8周的体质量、肺荷菌量及组织病理学改变在各组之间差异,以验证小鼠体内是否存在RFP依赖现象。比较RFP耐药株和依赖株的rpoB基因突变位点,以鉴定RFP依赖株的特征。数据以(x±s)表示,采用SPSS 11.0软件,组间比较采用单因素方差分析,以 P<0.01为差异有统计学意义。  结果  从46例RFP耐药的结核分枝杆菌临床分离株中筛选到18例RFP耐药伴依赖的菌株和28例RFP耐药非依赖的菌株。感染小鼠模型给药8周,各组小鼠的活菌计数从高到低依次为:RFP20组(lgCFU为6.60±0.82)、RFP10组(lgCFU为6.44±0.36)、Rfb10组(lgCFU为6.32±0.55)、对照组(lgCFU为6.20±0.28),接近于最初感染的菌量(lgCFU为5.93±0.14),但与对照组相比差异无统计学意义(F值分别为0.68、2.21、2.45,各组P值均大于0.05)。RFP耐药株8例和依赖株11例,分别有3/8和4/11的菌株在rpoB基因526位发生突变,2/8和6/11的菌株在rpoB基因531位发生突变。  结论  RFP临床耐药株中RFP依赖菌的检出率高,其RFP依赖现象在小鼠体内得到初步验证。RFP耐药株和依赖株的rpoB基因突变位点基本相同,因此RFP依赖的原因是表型变异还是其他因素尚有待进一步的实验证实。

关键词: 分枝杆菌, 结核, 利福平, 细菌蛋白质类, 突变

Abstract: Objective  To validate the rifampicin (RFP)dependent characteristics of M. tuberculosis clinical isolate in mice, and identify the characteristics of RFPdependent strains.   Methods  RFP-dependent strains were selected from RFP-resistant clinical isolates on 7H11 medium (the final concentrations of rifampicin were 1 μg/ml and 10 μg/ml). The dependence was further studied in mouse TB model, in which the mice were treated with 0.5% carboxymethyl cellulose sodium (control group), 10 mg/kg rifabutin (Rfb10 group), 10 mg/kg RFP (RFP10 group) and 20 mg/kg RFP (RFP20 group), respectively. The differences of rpoB gene mutations between RFP-dependent and non-dependent strains were analyzed.   Results  18 of 46 RFP-resistant isolates were RFP-dependent. After treatment with RFP or Rfb for 8 weeks in mouse model challenged by aerosol with RFP-dependent clinical isolate,the lung CFU counts showed a concentration-dependent increase (RFP20 group lgCFU were 6.60±0.82, RFP10 group 6.44±0.36、Rfb10 group 6.32±0.55、control group 6.20±0.28),but there were not significant difference in comparasion with control group (F value were 0.68, 2.21, 2.45, P>0.05). Five of 8 RFP-dependent strains and 10 of 11 non-dependent strains had mutations of  rpoB codon 526 and 531, respectively.   Conclusion  RFP-dependent strains did exist and showed a high prevalence, and the dependence was further validated in mouse TB model. The RFPdependent and non-dependent strains had common rpoB mutations, whether the dependence is a result of phenotype variation needs more evidence.

Key words: Mycobacterium tuberculosis, Rifampicin, Bacterial proteins, Mutation