Abstract
Background & Objectives: Globally, tuberculosis (TB) still remains a major public health problem. India is a high TB burden country contributing to 26 per cent of global TB burden. Pulmonary tuberculosis (PTB) cases are more common (~ 90% of cases) while extra pulmonary tuberculosis (EPTB) constitutes around 10 to 20% of all tuberculosis cases in India. The diagnosis of the EPTB cases is difficult because of few bacilli and consequently is associated with low sensitivity of Zhiel-Neelson (ZN) smear and culture on LJ media. The present study evaluates the utility of PCR for the detection of M. tuberculosis in paucibacillary extra pulmonary and pulmonary tuberculosis samples. Methods: A total of 561 samples (553 EPTB & 8 PTB cases) were collected from the extra pulmonary and pulmonary tuberculosis patients which were processed for ZN smear, culture on LJ media and conventional PCR using two gene targets (IS6110 and MPB64). Results: The PCR positivity of IS6110 and MPB64 gene targets was found to be 91.3% (N=63/69) and 89.9% (N= 62/69) in majority of smear negative & culture positive (as a gold standard) extra pulmonary cases, respectively. However the PCR positivity was observed 100% in smear positive, culture positive Line probe assay tested MDR PTB cases (true positive controls; N=34). Further the PCR specificity was determined >95% (true negative healthy controls; N=26). The positivity of M. tuberculosis by IS6110 & MPB 64 gene targets was found to be range of 88% to 100% in various clinical paucibacillary extra pulmonary samples i.e. pleural fluid, ascitic fluid, lymph node, pus, CSF and others. Our data on 64 samples (non respiratory, n=63 & respiratory samples, n=1) revealed 40.6% positivity by Cobas TaqMan Real Time PCR (utilizing 16S rRNA probe; Roche, USA). Interpretation & Conclusion: Our data revealed that utility of both PCR and Real Time PCR in rapid diagnosis of M. tuberculosis in paucibacillary extra pulmonary tuberculosis samples in Indian scenario.
Highlights
Tuberculosis (TB) remains a major global health problem, despite the availability of highly efficacious treatment for decades
Conventional methods like smear and culture on Lowenstein-Jenson (LJ) Media are of limited use in the diagnosis of extra pulmonary tuberculosis cases which is associated with low sensitivity because of few bacillary load, smear microscopy has both the problems of sensitivity and specificity [3 -5]
The present study evaluates the utility of polymerase chain reaction (PCR) (IS6110 and MPB64 gene targets) & TaqMan Real Time-PCR in the detection of M.tuberculosis in majority of smear negative paucibacillary extra pulmonary samples in Indian scenario
Summary
Tuberculosis (TB) remains a major global health problem, despite the availability of highly efficacious treatment for decades. Methods: A total of 561 samples (553 EPTB & 8 PTB cases) were collected from the extra pulmonary and pulmonary tuberculosis patients which were processed for ZN smear, culture on LJ media and conventional PCR using two gene targets (IS6110 and MPB64). Results: The PCR positivity of IS6110 and MPB64 gene targets was found to be 91.3% (N=63/69) and 89.9% (N= 62/69) in majority of smear negative & culture positive (as a gold standard) extra pulmonary cases, respectively. The positivity of M. tuberculosis by IS6110 & MPB 64 gene targets was found to be range of 88% to 100% in various clinical paucibacillary extra pulmonary samples i.e. pleural fluid, ascitic fluid, lymph node, pus, CSF and others. Interpretation & Conclusion: Our data revealed that utility of both PCR and Real Time PCR in rapid diagnosis of M. tuberculosis in paucibacillary extra pulmonary tuberculosis samples in Indian scenario
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
