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^＊

Abstract：

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.