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Volume 24, Number 11—November 2018
Letter

Acquired Resistance to Antituberculosis Drugs

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To the Editor: We read with great interest the article by Loutet et al. on acquired resistance to antituberculosis drugs in low-burden settings, such as England, Wales, and Northern Ireland (1), and support their assertion that detecting acquired resistance should be a priority in high-burden settings. This objective is particularly urgent in Myanmar, where tuberculosis (TB) is highly endemic (2) and drug-resistant TB is present through both acquired drug resistance and direct transmission. Unfortunately, the overwhelming number of TB cases precluded routine phenotypic drug susceptibility testing (DST) of first- or second-line drugs, so we began using whole-genome sequencing (WGS), which enabled us to more rapidly diagnose drug-resistant TB (3). Here, we briefly describe 2 cases of acquired antituberculosis drug resistance detected by WGS.

Patient A, diagnosed with rifampin-susceptible TB by Xpert (Cepheid Inc., Sunnyvale, CA, USA), received a treatment regimen containing first-line drugs but failed to achieve smear conversion at the 3-month follow-up. WGS indicated that the isolate was resistant to isoniazid, streptomycin, and rifampin. WGS and phenotypic DST of the isolate at baseline revealed it was resistant to isoniazid and streptomycin. Isolates from before and after treatment differed by 2 single-nucleotide polymorphisms, suggesting that rifampin resistance was acquired during therapy (4). Patient B was diagnosed with rifampin-resistant TB and reported that he had started multidrug resistant (MDR) TB treatment 6 months earlier but failed to continue the treatment. WGS and phenotypic DST showed the case had been MDR TB (resistant to isoniazid, rifampin, and streptomycin, but sensitive to amikacin) at baseline but had become pre–extensively drug resistant (amikacin resistance was acquired during treatment).

Loutet et al. showed that WGS provides an effective way to evaluate TB drug resistance in low-endemicity settings (5). We believe WGS is even more vital to help direct MDR TB treatment in high-burden settings, to halt the continued spread of TB.

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Acknowledgments

Ethics approval for this study was given by the Ethics Review Committee of Department of Medical Research, Yangon, Myanmar.

This work was supported by the New Zealand Health Research Council (grant number 15/648 and 18/024).

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Htin Lin AungComments to Author , Wint Wint Nyunt, Yang Fong, Bruce Russell, Gregory M. Cook, and Si Thu Aung

Author affiliations: University of Otago, Dunedin, New Zealand (H.L. Aung, B. Russell, G.M. Cook); Ministry of Health and Sports, Yangon, Myanmar (W.W. Nyunt); Massey University, Palmerston North, New Zealand (Y. Fong); Ministry of Health and Sports, Naypyitaw, Myanmar (S.T. Aung)

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References

  1. Loutet  MG, Davidson  JA, Brown  T, Dedicoat  M, Thomas  HL, Lalor  MK. Acquired resistance to antituberculosis drugs in England, Wales, and Northern Ireland, 2000–2015. Emerg Infect Dis. 2018;24:52433. DOIPubMed
  2. World Health Organization (WHO). Global tuberculosis report 2017. Geneva: WHO; 2017 [cited 8 Mar 2018].
  3. Aung  HL, Nyunt  WW, Fong  Y, Cook  GM, Aung  ST. First 2 extensively drug-resistant tuberculosis cases from Myanmar treated with bedaquiline. Clin Infect Dis. 2017;65:5312. DOIPubMed
  4. Eldholm  V, Norheim  G, von der Lippe  B, Kinander  W, Dahle  UR, Caugant  DA, et al. Evolution of extensively drug-resistant Mycobacterium tuberculosis from a susceptible ancestor in a single patient. Genome Biol. 2014;15:490. DOIPubMed
  5. Walker  TM, Cruz  ALG, Peto  TE, Smith  EG, Esmail  H, Crook  DW. Tuberculosis is changing. Lancet Infect Dis. 2017;17:35961. DOIPubMed

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Cite This Article

DOI: 10.3201/eid2411.180465

Original Publication Date: 9/27/2018

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Table of Contents – Volume 24, Number 11—November 2018

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Please use the form below to submit correspondence to the authors or contact them at the following address:

Htin Lin Aung, Sir Charles Hercus Health Research Fellow, Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, PO Box 56, Dunedin, New Zealand

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Page created: October 17, 2018
Page updated: October 17, 2018
Page reviewed: October 17, 2018
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
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