RT Journal Article SR Electronic T1 Mutation analysis and treatment outcomes of Isoniazid monoresistant tuberculosis JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 464 DO 10.1183/13993003.congress-2020.464 VO 56 IS suppl 64 A1 Rajyalakshmi Gurram A1 Vijayakumar Kaminedi A1 Phanindra Vasu Kotti A1 Yamini Priyanka Chintha YR 2020 UL http://erj.ersjournals.com/content/56/suppl_64/464.abstract AB Introduction: Isoniazid is an important first line drug for the control of tuberculosis that we cannot afford to lose. Mutations associated with Isoniazid resistance are more complex and occur in multiple genes (inhA & katG).Aims & Objectives: The aim of this study is to describe genetic patterns of INH resistance via inhA & katG gene mutations and to evaluate treatment outcomes of patients with INH monoresistant tuberculosis.Methodology: One hundred and nineteen patients with INH-monoresistant tuberculosis confirmed by 1st Line LPA and liquid culture DST during the period March 2018 to March 2019 were retrospectively enrolled. Patients with MDR tuberculosis were excluded.Results: Of the 119 INH monoresistant patients included, 86(72.2%) were found to be resistant via katG gene mutation, 27(22.6%) had inhA gene mutation & 6(5.04%) had both. katG mutation was present in 10/12 patients with a history of previous INH usage-for the treatment of active TB(8 cases) & who received IPT(4 PLHA cases).103 patients (87.4%) had successful treatment outcome while 16 (12.6%) had unsuccessful treatment outcomes- 6 (4.2%) lost to follow up, 2 (1.68%) death, 2 (1.68%) failure, 3(2.52%) acquired resistance to other drugs on follow up and 3(2.52%) got transferred out. There was no difference in treatment outcome of inhA vs katG resistance (81.48% vs 88.37%) with a p value- 0.35.Conclusion: InhA vs KatG mutations of INH resistance did not affect the treatment outcomes of patients with INH-monoresistant TB. In spite of relatively complicated and heterogeneous treatment regimens, the patients with INH monoresistant TB had a high treatment success rate.INH monoresistance influences the usefulness of Isoniazid Preventive Therapy.FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 464.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).