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Nimmo C, Ortiz AT, Tan CCS, Pang J, Acman M, Millard J, Padayatchi N, Grant AD, O'Donnell M, Pym A, Brynildsrud OB, Eldholm V, Grandjean L, Didelot X, Balloux F, van Dorp L. Detection of a historic reservoir of bedaquiline/clofazimine resistance-associated variants in Mycobacterium tuberculosis. Genome Med 2024; 16:34. [PMID: 38374151 PMCID: PMC10877763 DOI: 10.1186/s13073-024-01289-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 01/19/2024] [Indexed: 02/21/2024] Open
Abstract
BACKGROUND Drug resistance in tuberculosis (TB) poses a major ongoing challenge to public health. The recent inclusion of bedaquiline into TB drug regimens has improved treatment outcomes, but this advance is threatened by the emergence of strains of Mycobacterium tuberculosis (Mtb) resistant to bedaquiline. Clinical bedaquiline resistance is most frequently conferred by off-target resistance-associated variants (RAVs) in the mmpR5 gene (Rv0678), the regulator of an efflux pump, which can also confer cross-resistance to clofazimine, another TB drug. METHODS We compiled a dataset of 3682 Mtb genomes, including 180 carrying variants in mmpR5, and its immediate background (i.e. mmpR5 promoter and adjacent mmpL5 gene), that have been associated to borderline (henceforth intermediate) or confirmed resistance to bedaquiline. We characterised the occurrence of all nonsynonymous mutations in mmpR5 in this dataset and estimated, using time-resolved phylogenetic methods, the age of their emergence. RESULTS We identified eight cases where RAVs were present in the genomes of strains collected prior to the use of bedaquiline in TB treatment regimes. Phylogenetic reconstruction points to multiple emergence events and circulation of RAVs in mmpR5, some estimated to predate the introduction of bedaquiline. However, epistatic interactions can complicate bedaquiline drug-susceptibility prediction from genetic sequence data. Indeed, in one clade, Ile67fs (a RAV when considered in isolation) was estimated to have emerged prior to the antibiotic era, together with a resistance reverting mmpL5 mutation. CONCLUSIONS The presence of a pre-existing reservoir of Mtb strains carrying bedaquiline RAVs prior to its clinical use augments the need for rapid drug susceptibility testing and individualised regimen selection to safeguard the use of bedaquiline in TB care and control.
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Affiliation(s)
- Camus Nimmo
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, UK.
- Division of Infection and Immunity, University College London, London, UK.
- Africa Health Research Institute, Durban, South Africa.
| | - Arturo Torres Ortiz
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, UK
- Department of Medicine, Imperial College, London, UK
| | - Cedric C S Tan
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, UK
| | - Juanita Pang
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, UK
- Division of Infection and Immunity, University College London, London, UK
| | - Mislav Acman
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, UK
| | - James Millard
- Africa Health Research Institute, Durban, South Africa
- Wellcome Trust Liverpool Glasgow Centre for Global Health Research, Liverpool, UK
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Nesri Padayatchi
- CAPRISA MRC-HIV-TB Pathogenesis and Treatment Research Unit, Durban, South Africa
| | - Alison D Grant
- Africa Health Research Institute, Durban, South Africa
- TB Centre, London School of Hygiene & Tropical Medicine, London, UK
| | - Max O'Donnell
- CAPRISA MRC-HIV-TB Pathogenesis and Treatment Research Unit, Durban, South Africa
- Department of Medicine & Epidemiology, Columbia University Irving Medical Center, New York, NY, USA
| | - Alex Pym
- Africa Health Research Institute, Durban, South Africa
| | - Ola B Brynildsrud
- Division of Infectious Diseases and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Vegard Eldholm
- Division of Infectious Diseases and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Louis Grandjean
- Division of Infection and Immunity, University College London, London, UK
- Laboratorio de Investigacion y Enfermedades Infecciosas, Universidad Peruana Cayetano Heredia, Lima, Peru
- Department of Infection, Immunity and Inflammation, Institute of Child Health, University College London, London, UK
| | - Xavier Didelot
- School of Life Sciences and Department of Statistics, University of Warwick, Coventry, UK
| | - François Balloux
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, UK.
| | - Lucy van Dorp
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, UK.
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