title: Evaluation of the microscopic observation drug susceptibility assay for the rapid detection of MDR-TB and XDR-TB in China: a prospective multicentre study.
abstract: OBJECTIVE
  To perform a multicentre study evaluating the performance of the microscopic observation drug susceptibility (MODS) assay for the detection of MDR-TB and XDR-TB in high-burden resource-limited settings.
  
  
  METHODS
  We performed a prospective diagnostic accuracy study of drug-resistant TB suspects from outpatient and inpatient settings in five laboratories in China. Sputum was tested by smear microscopy, liquid [mycobacterial growth indicator tube (MGIT)] culture and the MODS assay at each site. Drug susceptibility testing (DST) was by MODS and an indirect 1% proportion method. The reference standard for Mycobacterium tuberculosis detection was growth on MGIT culture; the 1% proportion method was the reference standard for rifampicin, isoniazid, ofloxacin, kanamycin and capreomycin DST.
  
  
  RESULTS
  M. tuberculosis was identified by reference standard culture among 213/532 (40.0%) drug-resistant TB suspects. Overall MODS sensitivity for M. tuberculosis detection was 87.8%-94.3% and specificity was 96.8%-100%. For drug-resistant TB diagnosis, excellent agreement was obtained for all drugs tested at the majority of sites. The accuracy was 87.1%-96.7% for rifampicin, 87.1%-93.3% for isoniazid, 92.7%-100% for ofloxacin, 90.9%-100% for kanamycin and 90.2%-100% for capreomycin. The median time to culture positivity was significantly shorter for MODS than for the MGIT liquid culture (8 days versus 11 days, P<0.001). The contamination rate ranged between 2.1% and 5.3%.
  
  
  CONCLUSIONS
  In the study settings, MODS provided high sensitivity and specificity for rapid diagnosis of TB and drug-resistant TB. We consider it to have a strong potential for timely detection of MDR-TB and XDR-TB in high-burden resource-limited settings.
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China.
authors.forename: Zikun
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Intensive Care Unit, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Qin
authors.affiliation: Department of Clinical Laboratory, First Teaching Hospital of Tianjin University of TCM, Tianjin 300193, China.
authors.forename: Jinghui
authors.initials: J
authors.lastname: Du
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Luo
authors.affiliation: Clinical Microbiology Laboratory, Shanghai First People's Hospital, Shanghai 200431, China.
authors.forename: Yaoxing
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Clinical Microbiology Laboratory, University of Hong Kong-Shenzhen Hospital, Shenzhen, Guangdong 518053, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650118, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Province Tuberculosis Reference Laboratory, Jiangxi Chest Hospital, Nanchang, Jiangxi 330006, China.
authors.forename: Guoliang
authors.initials: G
authors.lastname: Xiong
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China.
authors.forename: Xiaomeng
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China.
authors.forename: Weiting
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China lisir361@163.com.
authors.forename: Junming
authors.initials: J
authors.lastname: Li
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002681:China; D054908:Extensively Drug-Resistant Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods*; D008853:Microscopy / Q000379:methods; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents
keywords: diagnosis; drug resistance; second-line drugs; tuberculosis