Mutation in and genes associated with bedaquline resistance among drug-resistant tuberculosis patients: A pilot study from a high-burden setting in Northern India.

BACKGROUND

Mutations in atpE gene or transcriptional repressor Rv0678 gene associated with inhibition of adenosine 5'-triphosphate synthase and upregulation of efflux pumps, respectively, may potentially lead to in vitro resistance to bedaquiline. This is the first study from India, which looks at mutations associated with this novel drug.

METHODS

In 2019 (January to June), a total of 68 laboratory-confirmed pre-extensively drug-resistant tuberculosis (XDR-TB) (fluoroquinolone resistant [n = 52] and second-line injectables resistant [n = 12]) and 4 × DR-TB culture specimens were included. All specimens were evaluated for genetic analysis using predesigned primers of atpE and Rv0678 genes.

RESULTS

Among the pre-XDR-TB isolates (n = 64), there were no mutations found in either atpE or Rv0678. However, among the XDR-TB isolates (n = 4), one specimen (25%) was found to be associated with a mutation in atpE gene at position 49, resulting in the amino acid leucine replaced by proline (L-49-P). No mutations were observed with the Rv0678 gene.

CONCLUSION

In this study, genetic analysis showed that only one-fourth XDR-TB isolates had a mutation in the atpE gene; there were no other mutations found in the Rv0678 gene. To the best of our knowledge, this novel mutation (L-49-P) in atpE gene is being reported for the first time in northern India.