XPERT MYCOBACTERIUM TUBERCULOSIS/RIFAMPICIN ASSAY: A BOON IN TUBERCULOSIS DIAGNOSTICS
Objectives: Mycobacterium tuberculosis (MTB) remains one of the most significant causes of mortality and morbidity in developing countries
especially India. India has the highest burden of TB, with an estimated incidence figure of 2.1 million cases out of the 9 million cases of TB globally.
Diagnosis of TB relies on conventional microscopy and culture with drawbacks related to sensitivity, specificity, turn around time (TAT). The aim of
this study was to evaluate the performance of Xpert MTB/rifampicin (RIF) assay (GX) for MTB detection in pulmonary and extrapulmonary clinical
Methods: A total of 209 clinical specimens (182: pulmonary and 27: extrapulmonary) were processed using auramine smear, culture by mycobacteria growth indicator tube and GenXpert.
Results: The sensitivity of GenXpert was 62.63% for pulmonary and 55% for extrapulmonary samples. The sensitivity and specificity of GX were
100% for the smear positive cases. The sensitivity, specificity, positive predictive value, and negative predictive value of the GX for smear negative
cases were 67.8%, 97.5%, 90.4%, and 89.6%, respectively. RIF resistance was detected in 3.8% the samples.
Conclusion: GenXpert, with short TAT, high sensitivity, specificity and less technical expertise required is a promising tool in TB diagnostics for the
Keywords: GenXpert, Tuberculosis diagnosis, Molecular method, Rifampicin resistance.
2. Iram S, Zeenat A, Hussain S, Wasim Yusuf N, Aslam M. Rapid diagnosis of tuberculosis using Xpert MTB/RIF assay - Report from a developing country. Pak J Med Sci 2015;31(1):105-10.
3. Munir MK, Rehman S, Aasim M, Iqbal R, Saeed S. Comparison of Ziehl Neelson microscopy with GeneXpert for detection of Mycobacterium tuberculosis. IOSR J Dent Med Sci 2015;14(11):56-60.
4. Khatri GR, Frieden TR. Controlling tuberculosis in India. N Engl J Med 2002;347(18):1420-5.
5. Long R. Drug-resistant tuberculosis. CMAJ 2000;163(4):425-8.
6. Ryu YJ. Diagnosis of pulmonary tuberculosis: Recent advances and diagnostic algorithms. Tuberc Respir Dis (Seoul) 2015;78(2):64-71.
7. Marlowe EM, Novak-Weekley SM, Cumpio J, Sharp SE, Momeny MA, Babst A, et al. Evaluation of the Cepheid Xpert MTB/RIF assay for direct detection of Mycobacterium tuberculosis complex in respiratory specimens. J Clin Microbiol 2011;49(4):1621-3.
8. Smith I. Mycobacterium tuberculosis pathogenesis and molecular determinants of virulence. Clin Microbiol Rev 2003;16(3):463-96.
9. Yu MC, Chen HY, Wu MH, Huang WL, Kuo YM, Yu FL, et al. Evaluation of the rapid MGIT TBc identification test for culture confirmation of Mycobacterium tuberculosis complex strain detection. J Clin Microbiol 2011;49(3):802-7.
10. Alvarez-Uria G, Azcona JM, Midde M, Naik PK, Reddy S, Reddy R. Rapid diagnosis of pulmonary and extrapulmonary tuberculosis in HIV-infected patients. Comparison of LED fluorescent microscopy and the GeneXpert MTB/RIF assay in a district hospital in India. Tuberc Res Treat 2012;2012:932862.
11. Zeka AN, Tasbakan S, Cavusoglu C. Evaluation of the GeneXpert MTB/RIF assay for rapid diagnosis of tuberculosis and detection of rifampin resistance in pulmonary and extrapulmonary specimens. J Clin Microbiol 2011;49(12):4138-41.
12. Hillemann D, RÃ¼sch-Gerdes S, Boehme C, Richter E. Rapid molecular detection of extrapulmonary tuberculosis by the automated GeneXpert MTB/RIF system. J Clin Microbiol 2011;49(4):1202-5.
13. Moure R, MuÃ±oz L, Torres M, Santin M, MartÃn R, Alcaide F. Rapid detection of Mycobacterium tuberculosis complex and rifampin resistance in smear-negative clinical samples by use of an integrated real-time PCR method. J Clin Microbiol 2011;49(3):1137-9.
14. Boehme CC, Nabeta P, Hillemann D, Nicol MP, Shenai S, Krapp F, et al. Rapid molecular detection of tuberculosis and rifampin resistance. N Engl J Med 2010;363(11):1005-15.
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