Emerging Infectious Diseases (Mar 2021)

Clusters of Drug-Resistant Mycobacterium tuberculosis Detected by Whole-Genome Sequence Analysis of Nationwide Sample, Thailand, 2014–2017

  • Ditthawat Nonghanphithak,
  • Angkana Chaiprasert,
  • Saijai Smithtikarn,
  • Phalin Kamolwat,
  • Petchawan Pungrassami,
  • Virasakdi Chongsuvivatwong,
  • Surakameth Mahasirimongkol,
  • Wipa Reechaipichitkul,
  • Chaniya Leepiyasakulchai,
  • Jody E. Phelan,
  • David Blair,
  • Taane G. Clark,
  • Kiatichai Faksri

DOI
https://doi.org/10.3201/eid2703.204364
Journal volume & issue
Vol. 27, no. 3
pp. 813 – 822

Abstract

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Multidrug-resistant tuberculosis (MDR TB), pre-extensively drug-resistant tuberculosis (pre-XDR TB), and extensively drug-resistant tuberculosis (XDR TB) complicate disease control. We analyzed whole-genome sequence data for 579 phenotypically drug-resistant M. tuberculosis isolates (28% of available MDR/pre-XDR and all culturable XDR TB isolates collected in Thailand during 2014–2017). Most isolates were from lineage 2 (n = 482; 83.2%). Cluster analysis revealed that 281/579 isolates (48.5%) formed 89 clusters, including 205 MDR TB, 46 pre-XDR TB, 19 XDR TB, and 11 poly–drug-resistant TB isolates based on genotypic drug resistance. Members of most clusters had the same subset of drug resistance-associated mutations, supporting potential primary resistance in MDR TB (n = 176/205; 85.9%), pre-XDR TB (n = 29/46; 63.0%), and XDR TB (n = 14/19; 73.7%). Thirteen major clades were significantly associated with geography (p<0.001). Clusters of clonal origin contribute greatly to the high prevalence of drug-resistant TB in Thailand.

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