title: Comparative evaluation of GenoType MTBDRplus line probe assay with solid culture method in early diagnosis of multidrug resistant tuberculosis (MDR-TB) at a tertiary care centre in India.
abstract: BACKGROUND
  The objectives of the study were to compare the performance of line probe assay (GenoType MTBDRplus) with solid culture method for an early diagnosis of multidrug resistant tuberculosis (MDR-TB), and to study the mutation patterns associated with rpoB, katG and inhA genes at a tertiary care centre in north India.
  
  
  METHODS
  In this cross-sectional study, 269 previously treated sputum-smear acid-fast bacilli (AFB) positive MDR-TB suspects were enrolled from January to September 2012 at the All India Institute of Medical Sciences hospital, New Delhi. Line probe assay (LPA) was performed directly on the sputum specimens and the results were compared with that of conventional drug susceptibility testing (DST) on solid media [Lowenstein Jensen (LJ) method].
  
  
  RESULTS
  DST results by LPA and LJ methods were compared in 242 MDR-TB suspects. The LPA detected rifampicin (RIF) resistance in 70 of 71 cases, isoniazid (INH) resistance in 86 of 93 cases, and MDR-TB in 66 of 68 cases as compared to the conventional method. Overall (rifampicin, isoniazid and MDR-TB) concordance of the LPA with the conventional DST was 96%. Sensitivity and specificity were 98% and 99% respectively for detection of RIF resistance; 92% and 99% respectively for detection of INH resistance; 97% and 100% respectively for detection of MDR-TB. Frequencies of katG gene, inhA gene and combined katG and inhA gene mutations conferring all INH resistance were 72/87 (83%), 10/87 (11%) and 5/87 (6%) respectively. The turnaround time of the LPA test was 48 hours.
  
  
  CONCLUSIONS
  The LPA test provides an early diagnosis of monoresistance to isoniazid and rifampicin and is highly sensitive and specific for an early diagnosis of MDR-TB. Based on these findings, it is concluded that the LPA test can be useful in early diagnosis of drug resistant TB in high TB burden countries.
authors.affiliation: Department of Internal Medicine (Division of Research for Pulmonary, Critical Care & Sleep Medicine), All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Raj N
authors.initials: RN
authors.lastname: Yadav
authors.forename: Binit K
authors.initials: BK
authors.lastname: Singh
authors.forename: Surendra K
authors.initials: SK
authors.lastname: Sharma
authors.forename: Rohini
authors.initials: R
authors.lastname: Sharma
authors.forename: Manish
authors.initials: M
authors.lastname: Soneja
authors.forename: Vishnubhatla
authors.initials: V
authors.lastname: Sreenivas
authors.forename: Vithal P
authors.initials: VP
authors.lastname: Myneedu
authors.forename: Mahmud
authors.initials: M
authors.lastname: Hanif
authors.forename: Ashok
authors.initials: A
authors.lastname: Kumar
authors.forename: Kuldeep S
authors.initials: KS
authors.lastname: Sachdeva
authors.forename: Chinnambedu N
authors.initials: CN
authors.lastname: Paramasivan
authors.forename: Balasangameshwra
authors.initials: B
authors.lastname: Vollepore
authors.forename: Rahul
authors.initials: R
authors.lastname: Thakur
authors.forename: Neeraj
authors.initials: N
authors.lastname: Raizada
authors.forename: Suresh K
authors.initials: SK
authors.lastname: Arora
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Sinha
mesh_terms: D000328:Adult; D000904:Antibiotics, Antitubercular / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D002374:Catalase / Q000235:genetics; D003430:Cross-Sectional Studies; D046508:Culture Techniques; D024901:Drug Resistance, Multiple, Bacterial; D042241:Early Diagnosis; D005260:Female; D060005:Genotyping Techniques; D006801:Humans; D007194:India; D007538:Isoniazid / Q000494:pharmacology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques; D060885:Multiplex Polymerase Chain Reaction; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D010088:Oxidoreductases / Q000235:genetics; D012293:Rifampin / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D062606:Tertiary Care Centers; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D055815:Young Adult
chemical_list: D000904:Antibiotics, Antitubercular; D001426:Bacterial Proteins; D010088:Oxidoreductases; D002374:Catalase; C480353:katG protein, Mycobacterium tuberculosis; C085257:InhA protein, Mycobacterium; D007538:Isoniazid; D012293:Rifampin
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