Rapid Detection of Ethambutol-Resistant Mycobacterium tuberculosis from Sputum by High-Resolution Melting Analysis in Beijing, China

• Main Authors: Wang J, Zhao W, Liu R, Huo F, Dong L, Xue Y, Wang Y, Xue Z, Ma L, Pang Y
• Format: Article
• Language: English
• Published: Dove Medical Press 2020-10-01
• Series: Infection and Drug Resistance
• Subjects: tuberculosis; ethambutol; molecular diagnostic; embb; china
• Online Access: https://www.dovepress.com/rapid-detection-of-ethambutol-resistant-mycobacterium-tuberculosis-fro-peer-reviewed-article-IDR

Jun Wang,1,* Weijie Zhao,2,* Rongmei Liu,1,* Fengmin Huo,3 Lingling Dong,3 Yi Xue,3 Yufeng Wang,4 Zhongtan Xue,4 Liping Ma,1 Yu Pang3 1Department of Tuberculosis, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis & Thoracic Tumor Research Institute, Beijing 101149, People’s Republic of China; 2Clinical Trial Agency Office, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis & Thoracic Tumor Research Institute, Beijing 101149, People’s Republic of China; 3National Clinical Laboratory on Tuberculosis, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis & Thoracic Tumor Research Institute, Beijing 101149, People’s Republic of China; 4Department of Laboratory Quality Control, Innovation Alliance on Tuberculosis Diagnosis and Treatment (Beijing), Beijing 101149, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yu PangNational Clinical Laboratory on Tuberculosis, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis & Thoracic Tumor Research Institute, No. 9, Beiguan Street, Tongzhou District, Beijing 101149, People’s Republic of ChinaTel/Fax [phone]Email [e-mail] MaDepartment of Tuberculosis, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis & Thoracic Tumor Research Institute, No. 9, Beiguan Street, Tongzhou District, Beijing 101149, People’s Republic of ChinaTel/Fax [phone]Email [e-mail]: We conducted a retrospective study to evaluate the performance of MeltPro assay for detecting ethambutol (EMB) susceptibility of Mycobacterium tuberculosis (MTB) isolates in sputum specimens in Beijing, China.Methods: Smear-positive TB patients undergoing MeltPro assay in the Beijing Chest Hospital between January 2019 and December 2019 were included. Phenotypic drug susceptibility testing (DST) was used as the reference standard to calculate the diagnostic accuracy of MeltPro assay for EMB resistance. Sanger sequencing of embB gene was conducted to resolve the discrepancies between MeltPro assay and phenotypic DST.Results: A total of 222 smear-positive patients were included in our analysis. The overall agreement rate between the two assays was 91.4%, with a kappa value of 0.78. Among 59 EMB-resistant TB cases diagnosed by DST, 49 were identified by MeltPro assay, demonstrating a sensitivity of 83.1%. In addition, 154 out of 163 EMB-susceptible patients diagnosed by DST were correctly detected with MeltPro assay, yielding a specificity of 93.9%. The probe frequency associated with the observed EMB-resistance was as follows: A (45/58), B (7/58), and D (6/58), and no EMB-resistance was associated with probe C. The presence of amino acid substitution was observed among all 9 cases with potentially “false-negative” results, including 7 with Met306Ile, 1 with Met306Val, 1 with Gly406Asp, respectively.Conclusion: MeltPro assay is a promising diagnostic tool for the detection of EMB resistance in China. The specific amino acid substitution in embB gene is the major reason for discrepancies between MeltPro assay and phenotypic DST.Keywords: tuberculosis, ethambutol, molecular diagnostic, embB, China