Tamilzhalagan Sembulingam, Shanmugam Sivakumar, Selvaraj Ashok, Suba Sakthi, Suganthi Chittibabu, Moonan Patrick K, Surie Diya, Sathyanarayanan Mukesh Kumar, Gomathi Narayanan Shivaram, Jayabal Lavanya, Sachdeva Kuldeep Singh, Selvaraju Sriram, Swaminathan Soumya, Tripathy Srikanth Prasad, Hall Patricia J, Ranganathan Uma Devi
ICMR-National Institute for Research in Tuberculosis, Chennai, India.
U.S. Centers for Disease Control and Prevention, Atlanta, GA, United States.
Front Microbiol. 2021 Nov 22;12:720436. doi: 10.3389/fmicb.2021.720436. eCollection 2021.
India has a high burden of drug-resistant tuberculosis (DR TB) and many cases go undetected by current drug susceptibility tests (DSTs). This study was conducted to identify rifampicin (RIF) and isoniazid (INH) resistance associated genetic mutations undetected by current clinical diagnostics amongst persons with DR TB in Chennai, India. Retrospectively stored 166 DR TB isolates during 2013-2016 were retrieved and cultured in Löwenstein-Jensen medium. Whole genome sequencing (WGS) and MGIT DST for RIF and INH were performed. Discordant genotypic and phenotypic sensitivity results were repeated for confirmation and the discrepant results considered final. Further, drug resistance-conferring mutations identified through WGS were analyzed for their presence as targets in current WHO-recommended molecular diagnostics. WGS detected additional mutations for rifampicin and isoniazid resistance than WHO-endorsed line probe assays. For RIF, WGS was able to identify an additional 10% (15/146) of mutant isolates associated with borderline rifampicin resistance compared to MGIT DST. WGS could detect additional DR TB cases than commercially available and WHO-endorsed molecular DST tests. WGS results reiterate the importance of the recent WHO revised critical concentrations of current MGIT DST to detect low-level resistance to rifampicin. WGS may help inform effective treatment selection for persons at risk of, or diagnosed with, DR TB.
印度耐多药结核病（DR-TB）负担沉重，目前的药物敏感性试验（DST）无法检测出许多病例。本研究旨在确定印度钦奈耐多药结核病患者中，当前临床诊断未检测到的与利福平（RIF）和异烟肼（INH）耐药相关的基因突变。检索了2013-2016年期间回顾性储存的166株耐多药结核分枝杆菌分离株，并在罗-琴培养基中培养。进行了全基因组测序（WGS）以及针对利福平和异烟肼的MGIT DST。对基因型和表型敏感性结果不一致的情况进行重复检测以确认，不一致的结果视为最终结果。此外，分析了通过WGS鉴定出的赋予耐药性的突变，看其是否作为当前世界卫生组织推荐的分子诊断中的靶点存在。与世界卫生组织认可的线性探针检测相比，WGS检测到了更多与利福平和异烟肼耐药相关的突变。对于利福平，与MGIT DST相比，WGS能够多鉴定出10%（15/146）与利福平临界耐药相关的突变菌株。与市售的和世界卫生组织认可的分子DST检测相比，WGS能够检测出更多的耐多药结核病病例。WGS结果重申了世界卫生组织最近修订的当前MGIT DST临界浓度对于检测对利福平低水平耐药的重要性。WGS可能有助于为有耐多药结核病风险或已被诊断为耐多药结核病的患者提供有效的治疗选择依据。
