A study on the mycobacterial burden and phenotypic drug resistance pattern with reference to the GeneXpert Cycle Threshold values in pulmonary tuberculosis

Authors

  • Bineeta Kashyap Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, New Delhi, India https://orcid.org/0000-0003-2471-4078
  • Krishna Sarkar Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, New Delhi, India https://orcid.org/0000-0003-4648-5237
  • Kapil Singh Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, New Delhi, India
  • Puneeta Hyanki DOTS Center, University College of Medical Sciences and Guru Teg Bahadur Hospital, New Delhi, India

DOI:

https://doi.org/10.15584/ejcem.2023.4.11

Keywords:

CBNAAT, cycle threshold values, rifampicin resistance, smear microscopy, tuberculosis

Abstract

Introduction and aim. Tuberculosis (TB) remains a significant global health challenge. Early and accurate diagnosis is crucial to prevent further transmission. The present study aimed to correlate cycle threshold values with smear microscopy and culture positivity, and determine cut-off cycle threshold values for levels of smear grade and culture positivity.

Material and methods. Forty presumptive cases of pulmonary TB were included and subjected to Ziehl- Neelsen stain, culture on Lowenstein Jensen media, CBNAAT and drug susceptibility testing for first line anti-tubercular drugs.

Results. Our study predicts 3+, 2+, and 1+ sputum smear grade at a cut-off of Ct value ≤ 16.74, ≤19.68, and ≤ 22.32 respectively. A strong positive correlation was found between time to culture positivity and Ct value. A cut-off of Ct value ≤22.32 predicts culture positivity with a sensitivity of 92%, and a specificity of 67%. None of the isolates showed rifampicin resistance by 1% proportion method.

Conclusion. Understanding the appropriate utilization of CBNAAT Ct values and their correlation with smear microscopy grade, culture, and drug susceptibility testing can assist clinicians in early identification and prompt initiation of appropriate treatment. This knowledge can contribute to the prevention of drug resistance, reduced transmission, and a decreased disease burden associated with TB.

Downloads

Download data is not yet available.

References

Tuberculosis 2023. World Health Organization. Available from: https://www.who.int/news-room/fact-sheets/detail/tuberculosis. Published April 21, 2023. Accessed August 14, 2023.

Najjingo I, Muttamba W, Kirenga BJ, et al. Comparison of GeneXpert cycle threshold values with smear microscopy and culture as a measure of mycobacterial burden in five regional referral hospitals of Uganda- A cross-sectional study. PLoS One. 2019;14(5):e0216901.doi: 10.1371/journal.pone.0216901

Lawn SD, Nicol MP. Xpert® MTB/RIF assay: development, evaluation and implementation of a new rapid molecular diagnostic for tuberculosis and rifampicin resistance. Future Microbiol. 2011;6(9):1067-1082.doi:10.2217/fmb.11.84

Steingart KR, Ng V, Henry M, et al. Sputum processing methods to improve the sensitivity of smear microscopy for tuberculosis: a systematic review. Lancet Infect Dis. 2006;6(10):664-674. doi: 10.1016/S1473-3099(06)70602-8

Moore DF, Guzman JA, Mikhail LT. Reduction in turnaround time for laboratory diagnosis of pulmonary tuberculosis by routine use of a nucleic acid amplification test. Diagn Microbiol Infect Dis. 2005;52(3):247-254. doi: 10.1016/j.diagmicrobio.2005.02.014

Fradejas I, Ontañón B, Muñoz-Gallego I, Ramírez-Vela MJ, López-Roa P. The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis. J Clin Tuberc Other Mycobact Dis. 2018;13:9-12. doi: 10.1016/j.jctube.2018.04.002

Agrawal 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;10(5):DC09-DC12. doi: 10.7860/JCDR/2016/18837.7755

Gilpin C, Korobitsyn A, Weyer K. Current tools available for the diagnosis of drug-resistant tuberculosis. Ther Adv Infect Dis. 2016;3(6):145-151. doi: 10.1177/2049936116673553

Laniado-Laborín R. Clinical challenges in the era of multiple and extensively drug-resistant tuberculosis. Rev Panam Salud Publica. 2017;41:e167. doi: 10.26633/RPSP.2017.167

Najjingo I, Muttamba W, Kirenga BJ, et al. Comparison of GeneXpert cycle threshold values with smear microscopy and culture as a measure of mycobacterial burden in five regional referral hospitals of Uganda- A cross-sectional study. PLoS One. 2019;14(5):e0216901. doi: 10.1371/journal.pone.0216901

Kassa GM, Merid MW, Muluneh AG, Fentie DT. Sputum smear grading and associated factors among bacteriologically confirmed pulmonary drug-resistant tuberculosis patients in Ethiopia. BMC Infect Dis. 2021;21(1):238. doi: 10.1186/s12879-021-05933-y

Palange P, Narang R, Kandi V. Evaluation of Culture Media for Isolation of Mycobacterium Species from Human Clinical Specimens. Cureus. 2016;8(8):e757. doi: 10.7759/cureus.757

Prakash AK, Datta B, Tripathy JP, Kumar N, Chatterjee P, Jaiswal A. The clinical utility of cycle of threshold value of GeneXpert MTB/RIF (CBNAAT) and its diagnostic accuracy in pulmonary and extra-pulmonary samples at a tertiary care center in India. Indian J Tuberc. 2018;65(4):296-302. doi: 10.1016/j.ijtb.2018.05.021

Beynon F, Theron G, Respeito D, et al. Correlation of Xpert MTB/RIF with measures to assess Mycobacterium tuberculosis bacillary burden in high HIV burden areas of Southern Africa. Sci Rep. 2018;8(1):5201. doi: 10.1038/s41598-018-23066-2

Pagano GC, Pereira GR, D'Ávila KG, Monaiar LR, Silva DR. Association between Xpert MTB/RIF cycle threshold values and sputum smear microscopy in patients with pulmonary tuberculosis. J Bras Pneumol. 2021;47(2):e20200549. doi: 10.36416/1806-3756/e20200549

Downloads

Published

2023-12-30

How to Cite

Kashyap, B., Sarkar, K., Singh, K., & Hyanki, P. (2023). A study on the mycobacterial burden and phenotypic drug resistance pattern with reference to the GeneXpert Cycle Threshold values in pulmonary tuberculosis. European Journal of Clinical and Experimental Medicine, 21(4), 730–735. https://doi.org/10.15584/ejcem.2023.4.11

Issue

Vol. 21 No. 4 (2023)

Section

ORIGINAL PAPERS

License

Copyright (c) 2023 European Journal of Clinical and Experimental Medicine

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Our open access policy is in accordance with the Budapest Open Access Initiative (BOAI) definition: this means that articles have free availability on the public Internet, permitting any users to read, download, copy, distribute, print, search, or link to the full texts of these articles, crawl them for indexing, pass them as data to software, or use them for any other lawful purpose, without financial, legal, or technical barriers other than those inseparable from having access to the Internet itself.

All articles are published with free open access under the CC-BY Creative Commons attribution license (the current version is CC-BY, version 4.0). If you submit your paper for publication by the Eur J Clin Exp Med, you agree to have the CC-BY license applied to your work. Under this Open Access license, you, as the author, agree that anyone may download and read the paper for free. In addition, the article may be reused and quoted provided that the original published version is cited. This facilitates freedom in re-use and also ensures that Eur J Clin Exp Med content can be mined without barriers for the research needs.