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Chinese Journal of Antituberculosis ›› 2018, Vol. 40 ›› Issue (8): 821-824.doi: 10.3969/j.issn.1000-6621.2018.08.009

• Original Articles • Previous Articles     Next Articles

Correlation analysis between inhA gene mutation and protionamide-resistance in multidrug resistance and extensively drug-resistant Mycobacterium tuberculosis

Yan-hua SONG,Gui-rong WANG,Feng-min HUO,Rong-mei LIU,Meng-qiu GAO(),Qi. LI()   

  1. The Second Department of Tuberculosis, Beijing Chest Hospital, Capital Medical University, Beijing 101149, China
  • Received:2018-04-19 Online:2018-08-10 Published:2018-09-09
  • Contact: Meng-qiu GAO,Qi. LI E-mail:gaomqwdm@aliyun.com;lq0703@hotmail.com

Abstract:

Objective To investigate the characteristics of mutations in genes katG and inhA and their association with resistance to protionamide (PTH) in the clinical strains of multidrug resistance Mycobacterium tuberculosis (MDR-MTB) and extensively drug-resistant Mycobacterium tuberculosis (XDR-MTB).Methods A total of 132 patients with MDR-TB or XDR-TB diagnosed in Beijing Chest Hospital, Capital Medical University from February 2016 to February 2017 were selected as the subjects of this study. The clinical isolates of these subjects were culture-positive and identified as MTB. The results of drug sensitivity test for isoniazid (INH), rifampicin (RFP), levofloxacin (Lfx), amikacin (Am), capreomycin (Cm) and PTH and the data of mutations in katG and inhA were available. The characteristics of katG and inhA mutations in MTB clinical isolates and their correlation with resis-tance to PTH were analyzed.Results Among the 132 clinical isolates, 89 (67.4%) were MDR-MTB, 26 (19.7%) were pre-XDR-MTB and 17 (12.9%) were XDR-MTB. The total resistance rate of PTH was 22.7% (30/132), and the rates were 11.2% (10/89), 30.8% (8/26) and 70.6% (12/17) in MDR-MTB, pre-XDR-MTB and XDR-MTB, respectively. The resistance rate of XDR-MTB to PTH was significantly higher than that of MDR-MTB (χ 2=30.57, P<0.01) and pre-XDR-MTB (χ 2=6.55, P<0.05). The mutation rate of inhA (with or without katG mutation) was 19.1% (17/89), 23.1% (6/26) and 17.6% (3/17) in MDR-MTB, pre-XDR-MTB and XDR-MTB strains, respectively. In PTH resistant strains of MDR-MTB, pre-XDR-MTB and XDR-MTB, only 5/10, 4/8 and 3/12 had inhA gene mutation. Conclusion From MDR-MTB to XDR-MTB clinical strains, the proportion of PTH resistance was increased significantly, and the mutation rate of inhA gene was decreased. The mutation in inhA gene may not be the main molecular mechanism of PTH resistance in XDR-MTB, and the strains without inhA mutation are not sure to be sensitive to PTH.

Key words: Tuberculosis, multidrug-resistant, Protionamide, Drug resistance, Genes, Mutation, Causality