title: A multi-site validation in India of the line probe assay for the rapid diagnosis of multi-drug resistant tuberculosis directly from sputum specimens.
abstract: Rifampicin (R) and isoniazid (H) are key first-line anti-tuberculosis drugs. Failure to detect resistance to these two drugs early results in treatment failure and poor clinical outcomes. The study purpose was to validate the use of the GenoType MTBDRplus line probe assay (LPA) to detect resistance to R and H in Mycobacterium tuberculosis strains directly from smear-positive sputum samples in India.
  
  
  METHODS
  Smear positive sputum specimens from 320 patients were subjected to LPA and results compared against those from conventional Lowenstein Jensen (LJ) culture and drug susceptibility testing (C&DST). All specimens with discordant R DST results were subjected to either sequencing of the rpoB gene and/or repeat DST on liquid culture (MGIT 960) at a National Reference Laboratory.
  
  
  RESULTS
  Significantly higher proportion of interpretable results were observed with LPA compared to LJ C&DST (94% vs. 80%, p-value <0.01). A total of 248 patients had both LJ and LPA DST results available; 232 (93.5%) had concordant R DST results. Among the 16 discordant R DST results, 13 (81%) were resolved in agreement with LPA results. Final LPA performance characteristics were sensitivity 96% (CI: 90%-98%), specificity 99% (CI: 95%-99%), positive predictive value 99% (CI: 95%-99%), and negative predictive value 95% (CI: 89%-98%). The median turnaround testing time, including specimen transportation time, on LPA was 11 days as compared with 89 days for LJ C&DST.
  
  
  CONCLUSIONS
  LPA proved highly accurate in the rapid detection of R resistance. The reduction in time to diagnosis may potentially enable earlier commencement of the appropriate drug therapy, leading to some reduction of transmission of drug-resistant strains.
authors.affiliation: Foundation for Innovative New Diagnostics, New Delhi, India.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Raizada
authors.affiliation: Central TB Division, Directorate General of Health Services, Ministry of Health and Family Welfare, Government of India, New Delhi, India.
authors.forename: K S
authors.initials: KS
authors.lastname: Sachdeva
authors.affiliation: National JALMA Institute for Leprosy and Other Mycobacterial Diseases, Agra, India.
authors.forename: D S
authors.initials: DS
authors.lastname: Chauhan
authors.affiliation: Sawai Man Singh Medical College, Jaipur, India.
authors.forename: Bharti
authors.initials: B
authors.lastname: Malhotra
authors.affiliation: Foundation for Innovative New Diagnostics, New Delhi, India.
authors.forename: Kishore
authors.initials: K
authors.lastname: Reddy
authors.affiliation: State TB Cell, Directorate of Health Services, Gujarat, India.
authors.forename: P V
authors.initials: PV
authors.lastname: Dave
authors.affiliation: UNITAID, Geneva, Switzerland.
authors.forename: Yamuna
authors.initials: Y
authors.lastname: Mundade
authors.affiliation: State TB Cell, Directorate of Health Services, Gujarat, India.
authors.forename: Pranav
authors.initials: P
authors.lastname: Patel
authors.affiliation: World Health Organization, New Delhi, India.
authors.forename: Ranjani
authors.initials: R
authors.lastname: Ramachandran
authors.affiliation: National JALMA Institute for Leprosy and Other Mycobacterial Diseases, Agra, India.
authors.forename: Ram
authors.initials: R
authors.lastname: Das
authors.affiliation: State TB Cell, Directorate of Health Services, Gujarat, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Solanki
authors.affiliation: Global TB Programme, World Health Organization, Geneva, Switzerland.
authors.forename: Douglas Fraser
authors.initials: DF
authors.lastname: Wares
authors.affiliation: Stop TB Partnership, Geneva, Switzerland.
authors.forename: Suvanand
authors.initials: S
authors.lastname: Sahu
authors.affiliation: Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland.
authors.forename: Rick
authors.initials: R
authors.lastname: O'Brien
authors.affiliation: Foundation for Innovative New Diagnostics, New Delhi, India.
authors.forename: C N
authors.initials: CN
authors.lastname: Paramasivan
authors.affiliation: World Health Organization, New Delhi, India.
authors.forename: Puneet K
authors.initials: PK
authors.lastname: Dewan
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007194:India; D007538:Isoniazid / Q000494:pharmacology; D008297:Male; D008826:Microbial Sensitivity Tests; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D012293:Rifampin / Q000494:pharmacology; D013183:Sputum / Q000382:microbiology*; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis*
chemical_list: D007538:Isoniazid; D012293:Rifampin