Preliminary Analysis of Timely Diagnosis of Multidrug-Resistant Tuberculosis Using a Streamlined Molecular Diagnostic Process

DOI: 10.6525/TEB.20170314.33(5).002

Ting-Yi Chiang, Wei-Lun Huang, Shin-Yuan Fan, Chao-Chieh Tseng, Ru-Wen Jou

2017 Vol.33 NO.5

Correspondence Author: Ru-Wen Jou

  • Division of Chronic Infectious Diseases, Centers for Disease Control, Ministry of Health and Welfare, Taiwan


To improve utilization of molecular diagnostics for tuberculosis case management, we implement an algorithm for intensifying diagnosis for multidrug-resistant tuberculosis (MDR-TB). The GeneXpert MTB/RIF (Xpert) assay was adopted as an initial diagnostic for populations at high-risk of MDR-TB. Sputum sample identified by the Xpert as Mycobacterium tuberculosis complex (MTBC) with rifampin (RIF) resistance is subsequently and simultaneously tested using the GenoType MTBDRplus test for the detection of MDR-TB (resistance to rifampin [RIF] and isoniazid ), and the GenoType MTBDRslv2 for the identification of resistance to fluoroquinolones (FLQ) and second-line injectable drugs (SLIDs) including kanamycin, amikacin and capreomycin. We identified 902 MDR-TB cases from high-risk populations in January–April, 2016. Of the 902 cases, 303 (33.6%) were relapse, 206 (22.8%) were treatment failure, 21 (2.3%) were treatment default, 14 (1.5%) were MDR-TB contacts, and 358(39.7%) were from MDR high incidence area/countries. Of the 902 sputum samples tested, 38.5% (347/902) were MTBC positive and 5.2% (18/347) were RIF-resistant using the Xpert test. Of the 18 RIF-resistant specimens analyzed using the GenoType MTBDRplus test and the GenoType MTBDRsl test; we identified 10 MDR-TB and 8 RIF mono-resistant TB (RIFr). Of the 10 MDR-TB cases, 6 were susceptible to both FLQ and SLID, 2 were FLQ-resistant and SLID-susceptible and 2 were FLQ-susceptible and SLID-resistant. Six RIFr TB cases were susceptible to both FLQ and SLID, 2 were FLQ-susceptible and SLID-resistant. Among 10 MDR-TB cases, 2 were treatment failure, 1 was MDR-TB contact, 5 were relapse cases and 2 were from MDR-TB high burden countries (one was a businessman lived in Mainland China, the other was foreign spouse from Mainland China). The turnaround time for molecular detection of MDR-/XDR-TB was 3 working days, while 6 weeks for MDR-TB and 10 weeks for XDR-TB using conventional tests.