Osong Public Health and Research Perspectives (Oct 2023)

Drug resistance and the genotypic characteristics of and in rifampicin- and/or isoniazid-resistant isolates in central Vietnam

  • Thi Binh Nguyen Nguyen,
  • Thi Kieu Diem Nguyen,
  • Van Hue Trương,
  • Thi Tuyet Ngoc Tran,
  • van Bao Thang Phan,
  • Thi Tuyen Nguyen,
  • Hoang Bach Nguyen,
  • Viet Quynh Tram Ngo,
  • Van Tuan Mai,
  • Paola Molicotti

DOI
https://doi.org/10.24171/j.phrp.2023.0124
Journal volume & issue
Vol. 14, no. 5
pp. 347 – 355

Abstract

Read online

Objectives Tuberculosis (TB) and drug-resistant TB (DR-TB) are national health burdens in Vietnam. In this study, we investigated the prevalence of rifampicin (RIF) and/or isoniazid (isonicotinic acid hydrazide, INH) resistance in patients with suspected TB, and applied appropriate techniques to help rapidly target DR-TB. Methods In total, 1,547 clinical specimens were collected and cultured using the BACTEC MGIT system (Becton Dickinson and Co.). A resazurin microtiter assay (REMA) was used to determine the proportions of RIF and/or INH resistance. A real-time polymerase chain reaction panel with TaqMan probes was employed to identify the mutations of rpoB and katG associated with DR-TB in clinical isolates. Genotyping of the identified mutations was also performed. Results A total of 468 Mycobacterium tuberculosis isolates were identified using the REMA. Of these isolates, 106 (22.6%) were found to be resistant to 1 or both antibiotics. Of the resistant isolates, 74 isolates (69.8%) were resistant to isoniazid (INH) only, while 1 isolate (0.94%) was resistant to RIF only. Notably, 31 isolates (29.2%) were resistant to both antibiotics. Of the 41 phenotypically INH-resistant isolates, 19 (46.3%) had the Ser315Thr mutation. There were 8 different rpoB mutations in 22 (68.8%) of the RIF-resistant isolates. The most frequently detected mutations were at codons 531 (37.5%), 526 (18.8%), and 516 (6.3%). Conclusion To help prevent new cases of DR-TB in Vietnam, it is crucial to gain a comprehensive understanding of the genotypic DR-TB isolates.

Keywords