The World Health Organization (WHO) today published the third edition of the Catalogue of mutations in Mycobacterium tuberculosis complex and their association with drug resistance , providing the most comprehensive global reference to date for interpreting genomic mutations associated with drug-resistant tuberculosis (TB).
The updated catalogue strengthens the evidence base for molecular and sequencing-based drug resistance testing for TB, supporting more consistent interpretation and use of genomic data across laboratories, surveillance programmes, diagnostic developers and researchers worldwide.
“Rapid and accurate detection of drug resistance is essential to ensuring that people with tuberculosis receive the most effective treatment as early as possible,” said Dr Tereza Kasaeva, Director of WHO’s Department for HIV, TB, Hepatitis and Sexually Transmitted Infections. “As targeted next-generation sequencing technologies become increasingly accessible, this third edition substantially expands the global evidence available for interpreting drug resistance, including for newer and repurposed medicines, while strengthening guidance to support the consistent application of genomic results in practice.”
The third edition has been updated to:
- include data from more than 71 000 clinical Mycobacterium tuberculosis isolates from over 75 countries – representing 37% and 12% increases in volume and coverage over the second edition that was published in 2023;
- expand evidence for newer and repurposed anti-TB medicines, including pretomanid and cycloserine;
- incorporate updated bioinformatic and statistical methods to improve mutation classification;
- introduce an enhanced interpretation framework in which the Graded Mutation List is applied together with additional grading rules and other interpretation criteria to support appropriate interpretation of drug resistance;
- provide strengthened practical guidance and new FAQs to support users in understanding, applying and implementing the catalogue; and
- strengthen support for sequencing-based drug susceptibility testing, the development and evaluation of molecular diagnostics, and global TB drug resistance surveillance.
Tuberculosis remains a leading infectious disease killer worldwide. Drug-resistant TB continues to pose a major challenge, with fewer than one in two people affected accessing treatment, highlighting the urgent need to strengthen early detection of drug resistance and access to care.
The third edition builds on the first WHO mutation catalogue, published in 2021, and the second edition released in 2023, reflecting continued international collaboration among national TB programmes, supranational reference laboratories, academic institutions and technical partners to improve the evidence base for genomic drug-resistance testing.
