title: Rapid genotypic detection of rpoB and katG gene mutations in Mycobacterium tuberculosis clinical isolates from Northern India as determined by MAS-PCR.
abstract: BACKGROUND
  There is a growing need to develop rapid laboratory research methods to counter the menace of drug resistant tuberculosis (MDR-TB) cases worldwide especially in developing countries. The present study was undertaken to investigate the type and frequency of rpoB and katG mutations in rifampicin (RIF) and isoniazid (INH) resistant strains respectively of Mycobacterium tuberculosis (MTB) circulating in Northern India and to explore the utility of multiplex-allele-specific (MAS)-PCR assay for detection of drug-resistant MTB isolates in low resource set up.
  
  
  METHODS
  Phenotypic and genotypic drug susceptibility testing (DST) was performed on 354 MTB isolates.
  
  
  RESULTS
  Mutation in rpoB gene was found most frequently at codons 531, 526 and 516 (59.83%, 45.29% and 22.22%, respectively). Further, combinations of 2-3 point mutations were also observed in 19.66% of RIF-resistant MTB strains. The frequency of mutations in katG gene was found at codon 315 among 82.95% of the INH-resistant MTB isolates. MAS-PCR detected rpoB and katG mutations in phenotypically resistant isolates with sensitivities of 93% and 83% respectively.
  
  
  CONCLUSIONS
  MAS-PCR assays can be used for rapid detection of drug-resistant TB strains in routine diagnostic practice, enabling early administration of appropriate treatment regimens to the affected patients.
authors: Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
authors: Anamika
authors: A
authors: Gupta
authors: Pradyot
authors: P
authors: Prakash
authors: Surya K
authors: SK
authors: Singh
authors: Shampa
authors: S
authors: Anupurba
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D002374:Catalase / Q000235:genetics*; D004269:DNA, Bacterial / Q000032:analysis; D012321:DNA-Directed RNA Polymerases; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006801:Humans; D007194:India; D007538:Isoniazid / Q000494:pharmacology; D008297:Male; D058889:Molecular Typing / Q000379:methods; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D010641:Phenotype; D017354:Point Mutation; D012293:Rifampin / Q000494:pharmacology; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis / Q000382:microbiology*; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C505805:rpoB protein, Mycobacterium tuberculosis; D002374:Catalase; C480353:katG protein, Mycobacterium tuberculosis; D012321:DNA-Directed RNA Polymerases; D007538:Isoniazid; D012293:Rifampin