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Category: Volume 07 Issue 01 January 2019
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Title: GeneXpert or CBNAAT Based MTB Detection, Assay of Rifampicin Resistance and Comparison with Conventional Methods of Diagnosis

Authors: Sunil Kumar, Chandan Kumar, H.L. Mahto

 DOI: https://dx.doi.org/10.18535/jmscr/v7i1.202

Abstract

Introduction: GeneXpert is a Cartridge based DNA amplification test. It has high sensitivity and specificity in comparison to conventional methods of diagnosis like ZN staining and culture of Mycobacterium. It is also very rapid in comparison to conventional methods and in single setting MTB detection as well as Rifampicin resistance can be detected through this GeneXpert technique.

Material and Methods: Pulmonary and extra pulmonary samples as sputum, BAL, bronchoscopic aspirate, ascetic fluid, CSF, pleural effusion, are used. MTB detection is done with GeneXpert/MTB/RIF assay technique. ZN stain, LJ culture is done with the sample and comparison done with GeneXpert.

Results: Total 786 pulmonary and extra pulmonary samples are studied with GeneXpert technique. In which 520 pulmonary and 166 extra pulmonary samples are present. MTB detected in pulmonary samples are 101 (19.4%), in which 18 (n=101) are Rifampicin resistant. In extra pulmonary samples among 166 samples 26(15.6%) are MTB positive and 03(n=26) are Rifampicin resistant. Sensitivity and specificity both are high in GeneXpert than conventional methods of diagnosis like ZN staining and LJ culture.

Discussion and Conclusion: GeneXpert technique is rapid, sensitive, and very specific. In pulmonary and extra pulmonary cases specificity is almost 100% and sensitivity is also very high. Its diagnostic importance is increased many fold in smear negative pulmonary TB cases and extra pulmonary TB cases. Rifampicin resistance along with MTB detection can also be done with GeneXpert technique in single setting. The duration of time is also about 2 hour which is very short time period in comparison to conventional methods like Mycobacterium culture.

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Corresponding Author

Chandan Kumar

Tutor, Department of Microbiology, Nalanda Medical College, Kankarbagh main Road, near Bhutnath Road, Patna-800026, India

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