{
  "abstract": "Multidrug-resistant Mycobacterium tuberculosis (MDR-MTB) poses a major obstacle to global tuberculosis control. Although whole-genome sequencing (WGS) has advanced the detection of resistance-associated mutations, the contribution of structural variants (SVs) remains inadequately characterized due to the inherent limitations of short-read sequencing technologies in resolving repetitive genomic regions and large insertions or deletions. We applied Oxford Nanopore long-read sequencing to clinical MDR-MTB isolates and susceptible controls, complemented by Illumina short-read sequencing. Variants were identified using BCFtools and independently validated with SVIM-asm. Candidate resistance mutations were mapped against the 2023 World Health Organization (WHO) mutation catalogue. Functional validation of identified SVs was performed through heterologous expression in Mycobacterium smegmatis , minimum inhibitory concentration determination, Western blotting, and AlphaFold 3-based structural modeling. We identified two unclassified SVs within WHO-catalogued resistance genes: an IS6110 insertion in Rv0678 (c.59_60ins1358bp, p.Gln22fs) and a 131-bp deletion in ethA (c.135_265del, p.Trp45fs). While IS6110 -mediated disruption of Rv0678 has been previously associated with bedaquiline resistance, the ethA deletion represents a previously undescribed SV. Heterologous expression of the ethA deletion in Mycobacterium smegmatis conferred a 16-fold increase in the minimum inhibitory concentration of ethionamide (256 μg/mL vs. 16 μg/mL for wild-type), and AlphaFold 3 structural prediction provided a structural rationale for the loss of the C-terminal domain essential for monooxygenase activity. This study identifies a novel ethA SV conferring ethionamide resistance and provides functional validation of a specific Rv0678 IS6110 insertion allele, demonstrating the power of long-read sequencing to uncover both known and novel mechanisms of drug resistance in MDR-MTB.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Laboratory Medicine, The First Affiliated Hospital of Wenzhou Medical University",
    "School of Laboratory Medicine and Life Sciences, Wenzhou Medical University",
    "Department of Clinical Laboratory, Wenzhou Central Hospital",
    "Department of Infectious Diseases, Wenzhou Central Hospital",
    "Key Laboratory of Laboratory Medicine, Ministry of Education"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 12,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Qiongdan Wang"
    },
    {
      "affs": [
        1
      ],
      "name": "Yaya Geng"
    },
    {
      "affs": [
        2
      ],
      "name": "Lianpeng Wu"
    },
    {
      "affs": [
        2
      ],
      "name": "Dandan Xia"
    },
    {
      "affs": [
        1
      ],
      "name": "Ruini Li"
    },
    {
      "affs": [
        1
      ],
      "name": "Baozhu Hu"
    },
    {
      "affs": [
        1
      ],
      "name": "Shuai Gao"
    },
    {
      "affs": [
        1
      ],
      "name": "Jinfang Lu"
    },
    {
      "affs": [
        3
      ],
      "name": "Jianyi Dai"
    },
    {
      "affs": [
        1
      ],
      "name": "Feng Xu"
    },
    {
      "affs": [
        1,
        4
      ],
      "name": "Xiaoqun Zheng"
    },
    {
      "affs": [
        1,
        4
      ],
      "name": "Guangxin Xiang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fmw2e1gm44t1j.bib",
  "cited_by": 0,
  "doi": "10.3389/fmicb.2026.1929307",
  "fulltext_url": null,
  "id": "fmw2e1gm44t1j",
  "issns": [
    "1664-302X"
  ],
  "landing_url": "https://www.frontiersin.org/articles/10.3389/fmicb.2026.1929307/full",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2725|Tuberculosis Research and Epidemiology"
    ]
  ],
  "openalex": "W7223843547",
  "pdf_url": "https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2026.1929307/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-27",
  "publisher": "Frontiers Media SA",
  "ris": "https://research.draconitic.com/paper/fmw2e1gm44t1j.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:12Z",
      "native_id": "10.3389/fmicb.2026.1929307",
      "source": "crossref",
      "url": "https://www.frontiersin.org/articles/10.3389/fmicb.2026.1929307/full"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2725|Tuberculosis Research and Epidemiology",
      "subfield": "infectious-disease"
    }
  ],
  "title": "Long-read sequencing of clinical multidrug-resistant Mycobacterium tuberculosis reveals a novel ethA structural variant conferring ethionamide resistance",
  "title_text": "Long-read sequencing of clinical multidrug-resistant Mycobacterium tuberculosis reveals a novel ethA structural variant conferring ethionamide resistance",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:19:12Z",
  "url": "https://research.draconitic.com/paper/fmw2e1gm44t1j",
  "venue": "Frontiers in Microbiology",
  "versions": []
}