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This limits the treatment option for extensively drug-resistant tuberculosis (XDR-TB). The aim of this study was to determine and compare the minimum inhibitory concentration (MIC) by agar dilution and resazurin microtiter assay (REMA) along with the detection of mutations against linezolid and clofazimine in confirmed XDR-TB clinical isolates.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Results<\/jats:title>\n                <jats:p>A total of 169 isolates were found positive for <jats:italic>Mycobacterium tuberculosis<\/jats:italic> complex (MTBC). The MIC was determined by agar dilution and REMA methods. The isolates which showed non-susceptibility were further subjected to mutation detection by targeting\u00a0<jats:italic>rplC<\/jats:italic>\u00a0gene (linezolid) and\u00a0<jats:italic>Rv0678<\/jats:italic>\u00a0gene (clofazimine). The MIC for linezolid ranged from 0.125\u00a0\u00b5g\/ml to\u2009&gt;\u20092\u00a0\u00b5g\/ml and for clofazimine from 0.25\u00a0\u00b5g\/ml to\u2009&gt;\u20094\u00a0\u00b5g\/ml. The MIC<jats:sub>50<\/jats:sub>\u00a0and MIC<jats:sub>90<\/jats:sub>\u00a0for linezolid were 0.5\u00a0\u00b5g\/ml and 1\u00a0\u00b5g\/ml respectively while for clofazimine both were 1\u00a0\u00b5g\/ml. The essential and categorical agreement for linezolid was 97.63% and 95.26% and for clofazimine, both were 100%. The sequencing result of the\u00a0<jats:italic>rplC<\/jats:italic>\u00a0gene revealed a point mutation at position 460\u00a0bp, where thymine (T) was substituted for cytosine (C) while seven mutations were noted between 46 to 220\u00a0bp in <jats:italic>Rv0678\u00a0gene.<\/jats:italic><\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Conclusion<\/jats:title>\n                <jats:p>REMA method has been found to be more suitable in comparison to the agar dilution method due to lesser turnaround time. Mutations in\u00a0<jats:italic>rplC<\/jats:italic>\u00a0and\u00a0<jats:italic>Rv0678<\/jats:italic>\u00a0genes were reasons for drug resistance against linezolid and clofazimine respectively.<\/jats:p>\n              <\/jats:sec>","DOI":"10.1186\/s12866-022-02622-x","type":"journal-article","created":{"date-parts":[[2022,10,3]],"date-time":"2022-10-03T12:02:51Z","timestamp":1664798571000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Mutation detection and minimum inhibitory concentration determination against linezolid and clofazimine in confirmed XDR-TB clinical isolates"],"prefix":"10.1186","volume":"22","author":[{"given":"Kamal","family":"Singh","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Swati","family":"Sharma","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tuhina","family":"Banerjee","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ankush","family":"Gupta","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shampa","family":"Anupurba","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2022,10,3]]},"reference":[{"issue":"10","key":"2622_CR1","doi-asserted-by":"publisher","first-page":"1364","DOI":"10.1093\/cid\/ciu619","volume":"59","author":"ML Bastos","year":"2014","unstructured":"Bastos ML, Hussain H, Weyer K, Garcia-Garcia L, Leimane V, Leung CC, Narita M, Pen\u00e3 JM, Ponce-de-Leon A, Seung KJ. 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The consent to participate was waived by the Institute Ethical Committee of Institute of Medical Sciences, Banaras Hindu University, Varanasi. All methods were carried out in accordance with relevant guidelines and regulations.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Not applicable.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"The author(s) declare that they have no competing interests.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"236"}}