title: Performance of the MTBDRsl assay in Georgia.
abstract: METHODS
  The country of Georgia has a high burden of multi- (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB).
  
  
  OBJECTIVE
  To assess the performance of the GenoType® MTBDRsl assay in the detection of resistance to kanamycin (KM), capreomycin (CPM) and ofloxacin (OFX), and of XDR-TB.
  
  
  METHODS
  Consecutive acid-fast bacilli smear-positive sputum specimens identified as MDR-TB using the MTBDRplus test were evaluated with the MTBDRsl assay and conventional second-line drug susceptibility testing (DST).
  
  
  RESULTS
  Among 159 specimens, amplification was adequate in 154 (97%), including 9 of 9 culture-negative and 2 of 3 contaminated specimens. Second-line DST revealed that 17 (12%) Mycobacterium tuberculosis isolates were XDR-TB. Compared to DST, the MTBDRsl had 41% sensitivity and 98% specificity in detecting XDR-TB and 81% sensitivity and 99% specificity in detecting OFX resistance. Sensitivity was low in detecting resistance to KM (29%) and CPM (57%), while specificity was respectively 99% and 94%. Median times from sputum collection to second-line DST and MTBDRsl results were 70-104 vs. 10 days.
  
  
  CONCLUSIONS
  Although the MTBDRsl assay had a rapid turnaround time, detection of second-line drug resistance was poor compared to DST. Further genetic mutations associated with resistance to second-line drugs should be included in the assay to improve test performance and clinical utility.
authors.affiliation: National Center for Tuberculosis and Lung Diseases, Tbilisi, Georgia.
authors.forename: N
authors.initials: N
authors.lastname: Tukvadze
authors.affiliation: National Center for Tuberculosis and Lung Diseases, Tbilisi, Georgia.
authors.forename: N
authors.initials: N
authors.lastname: Bablishvili
authors.affiliation: National Center for Tuberculosis and Lung Diseases, Tbilisi, Georgia.
authors.forename: R
authors.initials: R
authors.lastname: Apsindzelashvili
authors.affiliation: Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Blumberg
authors.affiliation: Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Kempker
mesh_terms: D000995:Antitubercular Agents / Q000627:therapeutic use*; D002207:Capreomycin / Q000627:therapeutic use; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D054908:Extensively Drug-Resistant Tuberculosis / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology; D005240:Feasibility Studies; D005846:Georgia (Republic); D006801:Humans; D007612:Kanamycin / Q000627:therapeutic use; D008826:Microbial Sensitivity Tests; D025202:Molecular Diagnostic Techniques; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D015242:Ofloxacin / Q000627:therapeutic use; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013183:Sputum / Q000382:microbiology; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000188:drug therapy* / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000188:drug therapy* / Q000382:microbiology; D057188:Workflow
chemical_list: D000995:Antitubercular Agents; D002207:Capreomycin; D007612:Kanamycin; D015242:Ofloxacin