Li Guilian, Zhang Jingrui, Guo Qian, Jiang Yi, Wei Jianhao, Zhao Li-li, Zhao Xiuqin, Lu Jianxin, Wan Kanglin
Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China.
Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China; Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou 325035, Zhejiang, China; Laboratory, Shijiazhuang Gynecological and Obstetric Hospital, Shijiazhuang, Hebei, 050000, China.
PLoS One. 2015 Feb 19;10(2):e0119013. doi: 10.1371/journal.pone.0119013. eCollection 2015.
Isoniazid (INH) and rifampicin (RIF) are the two most effective drugs in tuberculosis therapy. Understanding the molecular mechanisms of resistance to these two drugs is essential to quickly diagnose multidrug-resistant (MDR) tuberculosis and extensive drug-resistant tuberculosis. Nine clinical Mycobacterium tuberculosis isolates resistant to only INH and RIF and 10 clinical pan-sensitive isolates were included to evaluate the expression of 20 putative drug efflux pump genes and sequence mutations in rpoB (RIF), katG (INH), the inhA promoter (INH), and oxyR-ahpC (INH). Nine and three MDR isolates were induced to overexpress efflux pump genes by INH and RIF, respectively. Eight and two efflux pump genes were induced to overexpress by INH and RIF in MDR isolates, respectively. drrA, drrB, efpA, jefA (Rv2459), mmr, Rv0849, Rv1634, and Rv1250 were overexpressed under INH or RIF stress. Most efflux pump genes were overexpressed under INH stress in a MDR isolates that carried the wild-type katG, inhA, and oxyR-ahpC associated with INH resistance than in those that carried mutations. The expression levels of 11 genes (efpA, Rv0849, Rv1250, P55 (Rv1410c), Rv1634, Rv2994, stp, Rv2459, pstB, drrA, and drrB) without drug inducement were significantly higher (P < 0.05) in nine MDR isolates than in 10 pan-sensitive isolates. In conclusion, efflux pumps may play an important role in INH acquired resistance in MDR M. tuberculosis, especially in those strains having no mutations in genes associated with INH resistance; basal expression levels of some efflux pump genes are higher in MDR isolates than in pan-sensitive isolates and the basal expressional differences may be helpful to diagnose and treat resistant tuberculosis.
异烟肼（INH）和利福平（RIF）是结核病治疗中最有效的两种药物。了解对这两种药物的耐药分子机制对于快速诊断耐多药（MDR）结核病和广泛耐药结核病至关重要。纳入了9株仅对INH和RIF耐药的临床结核分枝杆菌分离株以及10株临床全敏感分离株，以评估20个假定的药物外排泵基因的表达以及rpoB（RIF）、katG（INH）、inhA启动子（INH）和oxyR-ahpC（INH）中的序列突变。分别有9株和3株MDR分离株被INH和RIF诱导过表达外排泵基因。在MDR分离株中，分别有8个和2个外排泵基因被INH和RIF诱导过表达。drrA、drrB、efpA、jefA（Rv2459）、mmr、Rv0849、Rv1634和Rv1250在INH或RIF应激下过表达。在携带与INH耐药相关的野生型katG、inhA和oxyR-ahpC的MDR分离株中，大多数外排泵基因在INH应激下的过表达程度高于携带突变的分离株。在9株MDR分离株中，11个无药物诱导的基因（efpA、Rv0849、Rv1250、P55（Rv1410c）、Rv1634、Rv2994、stp、Rv2459、pstB、drrA和drrB）的表达水平显著高于10株全敏感分离株（P<0.05）。总之，外排泵可能在MDR结核分枝杆菌对INH的获得性耐药中起重要作用，尤其是在那些与INH耐药相关基因无突变的菌株中；一些外排泵基因在MDR分离株中的基础表达水平高于全敏感分离株，且基础表达差异可能有助于耐药结核病的诊断和治疗。
