Comparative evaluation of geneXpert MTB/RIF assay and Ziehl-Neelsen staining for the diagnosis of tuberculosis
DOI:
https://doi.org/10.3126/jkmc.v11i3.50787Keywords:
Microscopy, Mycobacterium tuberculosis, Polymerase chain reaction, SputumAbstract
Background: Ziehl-Neelsen (ZN) staining for the diagnosis of tuberculosis is frequently used. Since ZN smear technique has poor sensitivity, molecular tool like GeneXpert assay have recently been introduced in Nepal. This study compared GeneXpert MTB/RIF assay with ZN stain microscopy for the diagnosis of tuberculosis.
Objectives: To compare and evaluate GeneXpert MTB/RIF assay and Ziehl-Neelsen staining for the diagnosis of tuberculosis.
Methods: An analytical observational study was conducted in Manipal Teaching Hospital, Pokhara from February 2020 to August 2021 after ethical clearance. A total of 355 clinical specimens (Sputum, Broncho-alveolar lavage, pus, lymph node aspirate etc) were collected and processed for Zeihl-Neelson staining and GeneXpert assay as per the recommended guidelines.
Results: Zeihl-Neelson staining detected acid-fast bacilli (AFB) in 17 (4.78%) specimens, while GeneXpert assay showed positivity in 37 (10.42%). All the 17 smear positive sputum samples yielded positive result by GeneXpert also. AFB were not detected in any of the 318 samples negative by GeneXpert. Fifteen (83.3%) of the 18 specimens that showed high to medium density of bacilli by GeneXpert were positive by Ziehl-Neelsen staining. Only two (10.5%) of the 19 specimens with low bacillary density by GeneXpert were positive by Ziehl-Neelsen Staining. These differences were statistically significant (p <0.001). Out of 37 positive specimens, one yielded rifampicin resistant Mycobacterium tuberculosis.
Conclusion: ZN smear, though, rapid, lacks sensitivity. GeneXpert, on the other hand, can be relied upon, as it detected significantly higher number of cases, demonstrated bacillary density and drug resistance.
Downloads
References
Chakaya J, Khan M, Ntoumi F, Aklillu E, Fatima R, Mwaba P and et al. Global tuberculosis report 2020 – Reflections on the global TB burden, treatment and prevention efforts. Int J Infect D. 2021;113 Suppl 1 (Suppl 1):S7-12. [PubMed | Full Text | DOI]
Parsons LM, Somoskövi A, Gutierrez C, Lee E, Paramasivan CN, Abimiku A, Spector S, Roscigno G, Nkengasong J. Laboratory diagnosis of tuberculosis in resource-poor countries: challenges and opportunities. Clin Microbiol Rev. 2011 Apr;24(2):314- 50. [PubMed | Full Text | DOI]
Mechal Y, Benaissa E, Mrimar EN, Benlahlou Y, Bssaibis F, Zegmout A et al. Evaluation of GeneXpert MTB/RIF system performances in the diagnosis of extrapulmonary tuberculosis. BMC Infect Dis. 2019 Dec 19, 1069:1-8. [Full Text | DOI]
Elizabeth R, Stephen L Mouser. Technique of lumbar puncture. In; Harrison’s Principles of Internal Medicine. 19th Ed, New York, Mc Graw Hill education. 443e-2-3p. [Full Text]
RNTCP Central TB Division. Module for Laboratory Technicians, New Delhi, India, Directorate General of Health Services, Ministry of Helath and Family Welfare. 2nd Edition, 2005, Oct :12-24. [Full Text]
WHO XpertMTB/RIF implementation manual: technical and operational “how to” practical consideration. WHO Press, France: GPS Publishing, 2014. [Full Text]
Tostmann A, Kik SV, Kalisvaart NA, Sebek MM, Verver S, Boeree MJ, et al. Tuberculosis transmission by patients with smear-negative pulmonary tuberculosis in a large cohort in the Netherlands. Clin Infect Dis. 2008 Nov 1;47(9):1135-42. [PubMed | Full Text | DOI]
Agarwal M, Bajaj A, Bhatia V, Dutt S. Comparative Study of GeneXpert with ZN Stain and Culture in Samples of Suspected Pulmonary Tuberculosis. J Clin Diagn Res. 2016 May;10(5): 9-12. [PubMed | Full Text | DOI]
Piersimoni C, Scarparo C, Piccoli P, Rigon A, Ruggiero G, Nista D, Bornigia S. Performance assessment of two commercial amplification assays for direct detection of Mycobacterium tuberculosis complex from respiratory and extrapulmonary specimens. J Clin Microbiol. 2002;40: 4138-42. [Full Text | DOI]
Munir MK, Rehman S, Aasim M, Iqbal R, Saeed S. Comparison of Ziehl-Neelsen microscopy with GeneXpert for detection of Mycobacterium tuberculosis. IOSR J Dent and Med Sci 2015;14(11):56- 60. [Full Text | DOI]
Nakata P, Patil S, Patil S, Purohit H, Shelke Y. Comparison of diagnostic efficacy of GeneXpert assay with Ziehl-Neelsen staining and microscopy in diagnosis of pulmonary tuberculosis. IP Int J of Med Microbiol and Trop Dis. 2019;5(4):218-21. [Full Text | DOI]
Chinedum OK, Emwiomwan A, Ifeanyi OE, Babayi A. Comparative Analysis of Ziehl-Neelsen and GeneXpert Techniques for the Diagnosis of Tuberculosis in Human Immunodeficiency Virus Positive Patients in Benin City. Ann of Clin and lab Res. 2017;5(4):1-6. [Full Text | DOI]
Umair M, Siddiqui S, Farooq M. Diagnostic Accuracy of Sputum Microscopy in Comparison with GeneXpert in Pulmonary Tuberculosis. Cureus. 2020 Nov 8;12(11):e11383. [PubMed | Full Text | DOI]
Mvelase NR, Mlisana KP. Xpert MTB/XDR for rapid detection of drug-resistant tuberculosis beyond rifampicin. The Lancet. 2022 Feb 1;2(22):156-7. [PubMed | Full Text | DOI]
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2022 Journal of Kathmandu Medical College
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Copyright © Journal of Kathmandu Medical College
The ideas and opinions expressed by authors or articles summarized, quoted, or published in full text in this journal represent only the opinions of the authors and do not necessarily reflect the official policy of Journal of Kathmandu Medical College or the institute with which the author(s) is/are affiliated, unless so specified.
Authors convey all copyright ownership, including any and all rights incidental thereto, exclusively to JKMC, in the event that such work is published by JKMC. JKMC shall own the work, including 1) copyright; 2) the right to grant permission to republish the article in whole or in part, with or without fee; 3) the right to produce preprints or reprints and translate into languages other than English for sale or free distribution; and 4) the right to republish the work in a collection of articles in any other mechanical or electronic format.
