title: Role of multiplex polymerase chain reaction using IS6110 and Protein b for the diagnosis of extra-pulmonary tuberculosis: North India.
abstract: BACKGROUND
  Prompt and accurate diagnosis of extra-pulmonary tuberculosis (TB) is highly challenging. Current conventional techniques lack sensitivity and are time-consuming. Here, we report our experience with multiplex polymerase chain reaction (MPCR) using two targets namely IS6110 and protein antigen b in the diagnosis of extra-pulmonary TB.
  
  
  METHODS
  A total of 150 patients of extra-pulmonary TB visiting tertiary care center in north India between September 2008 and December 2009 were included in the study. Sixty-six biopsy samples and 84 were body fluids from these patients were subjected for microscopy (Ziehl-Neelsen), culture on LJ medium and for Multiplex PCR using IS6110 and Protein b antigen.
  
  
  RESULTS
  Smear positivity was noted in 11 samples (7.33%), and LJ culture yielded Mycobacterium tuberculosis in 8 biopsies and 9 body fluids with overall positivity of 11.3%. The multi-targeted PCR could detect M. tuberculosis in a total of 112 samples. Of 112 positive samples, only Protein b band was detected in 7 samples and only IS6110 was detected in 5 samples. Overall Protein b, PCR could detect 71.33% of the cases, whereas IS6110 was positive in 66.6% of the cases. Overall the sensitivities of microscopy, culture, IS6110 PCR, Protein b PCR and MPCR were 7.33%, 11.3%, 66.67%, 71.3% and 74.6%, respectively. Thus by using more than two targets the sensitivity increased from 66.67% of IS6110 to 74.6% in MPCR.
  
  
  CONCLUSIONS
  Multiplex polymerase chain reaction using IS6110 and Protein b antigen is a highly sensitive and specific tool in the diagnosis of pauci-bacillary conditions like extra-pulmonary TB.
authors: Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors: Kusum
authors: K
authors: Sharma
authors: Suma B
authors: SB
authors: Appannanavar
authors: Manish
authors: M
authors: Modi
authors: Malkit
authors: M
authors: Singh
authors: Aman
authors: A
authors: Sharma
authors: Subhash
authors: S
authors: Varma
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics*; D001431:Bacteriological Techniques / Q000379:methods; D001706:Biopsy; D001826:Body Fluids; D003470:Culture Media / Q000737:chemistry; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics*; D006801:Humans; D007194:India; D008853:Microscopy / Q000379:methods; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D062606:Tertiary Care Centers; D014376:Tuberculosis / Q000175:diagnosis*
chemical_list: D000942:Antigens, Bacterial; D003470:Culture Media; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; C065517:protein antigen b, Mycobacterium