title: Evaluation of genotype MTBDRsl assay to detect drug resistance associated with fluoroquinolones, aminoglycosides and ethambutol on clinical sediments.
abstract: BACKGROUND
  The emergence of resistant tuberculosis (TB) is a major setback to the global control of the disease as the treatment of such resistance is complex and expensive. Use of direct detection of mutations by molecular methods could facilitate rapid diagnosis of resistance to offset diagnostic delays. We evaluated the performance of the Genotype MTBDRsl (Hain Life Sciences) for the detection of second line resistant TB directly from stored smear positive sputum sediments.
  
  
  RESULTS
  The assay showed a diverse range of sensitivity and specificity, 91.26% [95% CI, 84-96] and 95.5% [95% CI, 87-99] for FQ (PPV ∼97% & NPV ∼ 87.67%), 56.19% [95%CI, 46-66] and 81% [95%CI, 66-91] for EMB (PPV ∼ 88.06% & NPV ∼ 43.21%) and 100% for SLD. Diagnostic accuracy for FQ, SLD and EMB was 94%, 100% and 63.51%, respectively. 1.17% (2/170) were heteroresistance strains, where the heteroresistance was linked to rrs gene. A varying rate of validity was observed 100% (170/170) for FQ, 94.11% (160/170) for EMB, 88.23% (150/170) for SLD.
  
  
  CONCLUSIONS
  Genotype MTBDRsl is simple, rapid, economical assay that can be used to detect commonly known resistance associated with Fluoroquinolone, second line injectable drugs and ethambutol. The assay detects the targeted resistance in less time as compared to phenotypic DST. But due to low NPV to FQ (88%) and EMB (43.21%), the assay results must be interpreted in coordination with the phenotypic DST.
authors.affiliation: Department of Microbiology, P. D. Hinduja Hospital and Medical Research Centre, Veer Sarvarkar Marg, Mahim, Mumbai, India.
authors.forename: Kanchan
authors.initials: K
authors.lastname: Ajbani
authors.forename: Chaitali
authors.initials: C
authors.lastname: Nikam
authors.forename: Mubin
authors.initials: M
authors.lastname: Kazi
authors.forename: Christen
authors.initials: C
authors.lastname: Gray
authors.forename: Catharina
authors.initials: C
authors.lastname: Boehme
authors.forename: Kavita
authors.initials: K
authors.lastname: Balan
authors.forename: Anjali
authors.initials: A
authors.lastname: Shetty
authors.forename: Camilla
authors.initials: C
authors.lastname: Rodrigues
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology; D000995:Antitubercular Agents / Q000494:pharmacology; D001483:Base Sequence; D003140:Communicable Disease Control / Q000379:methods*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004977:Ethambutol / Q000494:pharmacology; D024841:Fluoroquinolones / Q000494:pharmacology; D006801:Humans; D007194:India; D008826:Microbial Sensitivity Tests / Q000379:methods; D008969:Molecular Sequence Data; D060885:Multiplex Polymerase Chain Reaction; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics*; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D013183:Sputum / Q000382:microbiology; D018088:Tuberculosis, Multidrug-Resistant / Q000235:genetics* / Q000382:microbiology
chemical_list: D000617:Aminoglycosides; D000995:Antitubercular Agents; D024841:Fluoroquinolones; D004977:Ethambutol