|LETTER TO THE EDITOR
|Year : 2016 | Volume
| Issue : 3 | Page : 366-367
Drug-resistant tuberculosis among previously treated patients in Yangon, Myanmar
Thanda Tun1, Wint Wint Nyunt2, Khin Zaw Latt2, Ari Samaranayaka3, John A Crump4, Kyi Kyi Thinn5, Gregory M Cook6, Htin Lin Aung6
1 National Health Laboratory, Ministry of Health and Sports, Yangon, Myanmar
2 National Tuberculosis Reference Laboratory, Ministry of Health and Sports, Yangon, Myanmar
3 Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
4 Center for International Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
5 Department of Microbiology, University of Medicine, Yangon, Myanmar
6 Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
|Date of Web Publication||13-Feb-2017|
Htin Lin Aung
Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Post Office Box 56, Dunedin
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Tun T, Nyunt WW, Latt KZ, Samaranayaka A, Crump JA, Thinn KK, Cook GM, Aung HL. Drug-resistant tuberculosis among previously treated patients in Yangon, Myanmar. Int J Mycobacteriol 2016;5:366-7
|How to cite this URL:|
Tun T, Nyunt WW, Latt KZ, Samaranayaka A, Crump JA, Thinn KK, Cook GM, Aung HL. Drug-resistant tuberculosis among previously treated patients in Yangon, Myanmar. Int J Mycobacteriol [serial online] 2016 [cited 2020 Aug 4];5:366-7. Available from: http://www.ijmyco.org/text.asp?2016/5/3/366/200083
To the Editor,
Myanmar is one of 22 high tuberculosis (TB) burden countries with a high prevalence of drug-resistant Mycobacterium tuberculosis (MTB) . The Myanmar National Tuberculosis Program uses an algorithm to screen for patients at risk of multidrug-resistant TB (MDR-TB). Patients identified as high risk for MDT-TB are referred to the National Tuberculosis Reference Laboratories, where phenotypic drug susceptibility testing (DST) of the first-line anti-TB drugs isoniazid (INH), rifampicin, ethambutol, and streptomycin is performed for confirmation prior to enrollment in a MDR-TB treatment program . The nationwide drug-resistant TB survey conducted in 2012–2013 identified MDR-TB among 33 (11.2%) of 295 patients in Yangon compared with 35 (4.0%) of 866 outside Yangon. MDR-TB was confirmed among 16 (27.1%) of 58 previously treated patients . Here, we report factors associated with the occurrence of MDR-TB among previously treated TB patients in Yangon. We collected sputum samples with acid-fast bacilli grading 2+ or 3+ from 96 previously treated patients that were referred to the National Tuberculosis Reference Laboratory, Yangon, between October 2012 and August 2013. Isolates were tested for MDR-TB with molecular DST using the Hain GenoType MTBDRplus v1.0 (Hain Lifescience, Nehren, Germany) and phenotypic DST.
Among 96 patient MTB isolates, 80 (83.3%) were MDR by phenotypic DST. Factors associated with MDR-TB were identified by logistic regression analysis ([Table 1]). Patients in the 19–40 years age group were at greater risk for MDR-TB compared with the 41–60 years age group. Patients living in East and North Districts of Yangon Region were more likely to have MDR-TB than those living in South District. The East and North Districts have large urban populations depending on factory-based employment as well as a large proportion of migrant workers from other states and regions often living in crowded conditions . The most frequently observed resistance mutations were the rpoB S531L (rifampicin) and katG S315T (INH), identified in 67 (84.0%) and 77 (96.0%) of MDR isolates, respectively, and consistent with previous studies ,. One isolate had INH resistance results discrepant between the MTBDRplus and phenotypic DST result; INH-susceptible by MTBDRplus, but INH-resistance by phenotypic DST. We used whole-genome sequencing (WGS) to resolve this disagreement and detected a rare mutation G299C in katG conferring INH resistance in this isolate  highlighting the added value of WGS in the diagnosis of drug-resistant TB. Treatment after failure patients were more likely to have MDR-TB than relapse patients, suggesting that construction of effective regimens is needed to successfully treat drug-resistant TB patients. Given that WGS can identify known resistance mutations to most TB drugs, it can be used to guide personalized treatment of drug-resistant TB patients ,. In addition, sequencing costs are declining rapidly and fully automated analysis is increasingly available. Therefore, incorporation of WGS into drug-resistant TB management in low-resource settings is becoming feasible. In summary, rapid diagnostics such as GeneXpert at township TB centers especially in North and East Districts of Yangon Region and ultimately, whole-genome sequencing at the National TB Reference Laboratory should be considered for effective diagnosis and treatment to reduce transmission of MDR-TB in Yangon Region.
|Table 1: Association between factors and occurrence ofmultidrug-resistant tuberculosis (MDR-TB), Yangon, Myanmar, 2012–2013.|
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| Conflicts of interest|| |
The authors declared no conflicts of interest.
| Acknowledgments|| |
We thank the staff from the National TB Reference Laboratory in Yangon, Myanmar for technical support. T.T. received funding for travel and accommodation from the University of Otago Development Office to perform data analysis at the University of Otago, Dunedin, New Zealand. H.L A. was supported by the e-ASIA (East Asia) Joint Research Program Grant from the New Zealand Health Research Council (grant number 15/648). Ethical approval for this study was given by the Research and Ethical Committee of the University of Medicine, Yangon, Myanmar.
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