Background: Tuberculosis is the most common communicable disease causing morbidity and mortality worldwide. India is the country with the highest burden of MDR –TB. The WHO has endorsed CBNAAT in December 2010, an automated real time PCR based rapid diagnostic test, simultaneously detecting mycobacterium tuberculosis and rifampicin resistance within two hours.^1,2,3 WHO has recommended in 2013, the use CBNAAT in sputum AFB negative pulmonary tuberculosis, extra pulmonary tuberculosis, paediatric tuberculosis and in immune compromised patients like HIV and diabetes mellitus.^4,5,6  Various studies shows the prevalence of MDR/RR TB in previously treated patients.

Aim of the Study: This study was done to detect the rifampicin resistance in newly detected sputum AFB negative pulmonary tuberculosis patient through CBNAAT.

Material and Methods: This study includes 140 cases of Presumptive pulmonary tuberculosis patients who were smear negative during the period during the period between Nov 2016 to April 2018 in all presumptive pulmonary tuberculosis patients who attended OP or got admitted in Rajah Muthiah medical college and hospital, Chidambaram. These patients were enrolled and CBNAAT was provided.

Results: Out of these 140 cases, MTB was detected in 54 cases (38.6%) and in rest of the 86 cases MTB not detected. Among 54 cases, 2 were rifampicin resistance and rest of them were rifampicin sensitive. These 2 rifampicin resistance was diagnosed in newly detected pulmonary tuberculosis patients. This study shows the prevalence of 3.7% MDR-TB in primary pulmonary tuberculosis.

Conclusion: This study shows that CBNAAT is more superior to sputum microscopy by detecting additional pulmonary tuberculosis cases and drug resistance which are missed by sputum AFB stain within few hours. We concluded that all sputum AFB negative presumptive pulmonary tuberculosis patients should undergo novel technique like CBNAAT and LPA to diagnose the undetected TB and DR – TB.

Keywords: Sputum AFB negative, CBNAAT, New case, Rifampicin resistance

1. Helb D, jones M ,Story E, Boehme C, Wallace E, H K , Kop J, Owens MR, Rodgers R, Banada P, et al. Rapid detection of mycobacterium tuberculosis and rifampicin resistance by use of on demand , near patient technology. J ClinMicrobiol 2010; 48: 229 – 237.
2. Boehme CC, Nabeta P, Hillmann D, NicolMP, Shenai S, Krapp F , Allen J,Tahirli R, Blakemore R, rustomjee R, et al. Rapid molecular detection of tuberculosis and rifampicin resistance .N Eng J Med 2010: 363: 1005- 1015.
3. Van Rie A, page – Shipp L, Scott L, Sanne I, tevens W. Xpert MTB/RIF for pint of care diagnosis of TB in high – HIV burden, resource limited countries: hype or hope? Expert Rev MolDiagn 2010;10: 937 – 946.
4. Automated real time nucleic acid amplification technology for rapid and simultaneous detection of tuberculosis and rifampicin resistance: Xpert MTB/RIF system for the diagnosis of pulmonary and extra pulmonary tuberculosis TB in adults and children : policy update. Geneva: World Health Organization, 2013. http://www.who. ot/tb/laboratory/policy_statements/en/)
5. Lawn SD, Nicol MP. Xpert MTB/RIF assay: development, evaluation and implementation of a new rapid molecular diagnostic for tuberculosis and rifampicin resistance. Future microbial 2011;6(9):1067-82
6. Guidance document for use of Catridge Based Nucleic Acid Amplification Test (CB-NAAT) under Revised National TB Control Programme (RNTCP) issued central TB division, directorate general of health services September 2013.
7. World Health Organization. Global tuberculosis report Geneva: WHO, 2016.
8. http://www.tbfacts.org
9. World Health Organization. Fluorescent light – emitting diode (LED) microscopy for diagnosis of tuberculosis. Policy statement. WHO/HTM/TB/2011.8.Geneva, Switzerland: WHO, 2011.
10. Stop TB Partnership and World Health Organization. New Laboratory Diagnostic Tools for TB control. Geneva, World Health Organization, 2008.
11. Manna N, Giri K, Mundle M et al. Drug resistance pattern, related socio demographic factor and prevalence practice among MDR-TB patients: An experience from a tertiary care setting. JDMS: 2014; 3 (9); 16-21.
12. Foundation for Innovative New Diagnostics. Performance of Xpert MTB/RIF version G4assay.Geneva: Foundation for innovative new diagnostics;2011.http://www.stoptb.org/wg/gli/assets/documents/map/findg4catridge.pdf.Accessed 22 Nov 2016.
13. Boehme CC, Nabeta P, Nicol et al. Feasibility, diagnostic accuracy , effectiveness of decentralized use of the Xpert MTB/RIF test for diagnosis of tuberculosis and multidrug resistance: Lancet a muticentric implementation study. 2011:377 (9776): 1495-1505.
14. Chakraborty S, Sen MK, Tyagi JS. Diagnosis of extra pulmonary tuberculosis by smear, culture, and PCR using sample processing technology. J Clin Microbiol.2005; 43:4357 – 62 PMID: 16145077.
15. Steingart KR, SchillerI, Horne DJ, PaiM, Boehme CC, Dendukuri N. Xpert® MTB/RIF assay for pulmonary tuberculosis and rifampicin resistance in adults(review). Cochrane Database Syst. Rev1:CD009593. http://dx. doi.org/ 10.1002/14651858. CD009593.pub2.doi:10.1002/14651858.CD009593 pub3PID:24448973.
16. Blackmore R, Story E, Helb D, et al. Evaluation of the analytical performance of the Xpert MTB/RIF assay. J Clin Microbial 2010;48 (7):2495-2501.
17. Sowjanya DS, Behera G, Reddy VVR, et al: Novel diagnostic tool for rapid and specific detection of Mycobacterium tuberculosis in pulmonary samples. IJHRMIMS 2014:28-31.
18. Rao KNM ,Vinod K, Ishwarappagol P, et al. Efficacy of CBNAAT in detecting sputum negative pulmonary tuberculosis.
19. Weyer k, Mirzayev F, Milgliori GB, Gemert WV, D’Ambrosio L, ZignolM.Rapid molecular TB diagnosis :evidence, policy making and global implementation of Xpert MTB/RIF.ERJ.2013;42(1): 252-71.
20. Pierre Lee Palud, Vincent Cattoir, Bridgitte Malbruny, Romain Magnier, Karine Campbell, Youssef Oilkhouir1, et al. Retrospective observational study of diagnostic accuracy of the Xpert MTB/RIF assay on the fiberoptic bronchoscopy sampling for early diagnosis of smear negative or smear scare patients with suspected tuberculosis. BMC Pulmonary Medicine 014;14:137.
21. Avashia S, Choubey S,Mishra S et al.To study the usefulness of CBNAAT (Catridge Based Nucleic Acid Amplification Test) in BAL (bronchoalveolar lavage) samples in the diagnosis of smear negative/non sputum producing patients with suspected tuberculosis.
22. Poojan Shrestha et al. The Application of Gene Xpert MTB/RIF for Smear Negative TB diagnosis as a fee paying service at a South Asian General Hospital.
23. NorinJ (May 2015) A retrospective evaluation of diagnostic accuracy of Xpert® MTB/RIF assay, used for detection of Mycobacterium tuberculosis in Greece.http://www.div-portal.se/smash/get/diva2:825390/FULLTEXT01.pdf.
24. Zeka AN, Tasbakan S, Cavusoglu C. Evaluation of the gene XpertMTB/RIF for rapid diagnosis of Tuberculosis and detection of rifampicin resistance in pulmonary and extra pulmonary tuberculosis. JClinMicrobiol. 2011; 49: 4138-41.
25. Geleta DA, Megerssa YC, Gudeta AN, et al. Xpert MTB/RIF assay for diagnosis of pulmonary tuberculosis in sputum specimen in remote care facility. BMC Microbiology 2015;15: 220.
26. Sharma SK, Kohli M, Yadav RN, et al. Evaluating the diagnostic accuracy of Xpert with ZN stain and culture in samples of suspected pulmonary tuberculosis. Journal of Clinical and Diagnostic Research 2016; 10(5):DC09-DC12.
27. Ramachandran R, Nalini S, Chandrasekar V, Dave PV, Sanghavi AS, Wares, et al. Surveillance of drug resistance tuberculosis in the state of Gujarat, India. Int J Tuberc Lung Dis 2009; 13(9): 1154-60.

Dr G. Nivetha

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.