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. 2019 Jan-Dec:33:2058738419827174.
doi: 10.1177/2058738419827174.

Detection of Mycobacterium tuberculosis in AFB smear-negative sputum specimens through MTB culture and GeneXpert® MTB/RIF assay

Ghulam Rasool  1 , Arif Muhammad Khan  2 , Raza Mohy-Ud-Din  3 , Muhammad Riaz  1
Affiliations

Detection of Mycobacterium tuberculosis in AFB smear-negative sputum specimens through MTB culture and GeneXpert® MTB/RIF assay

Ghulam Rasool et al. Int J Immunopathol Pharmacol. 2019 Jan-Dec.

Abstract

Tuberculosis (TB) is an important public health issue around the globe which is a chronic infectious disease and is still one of the major challenges for developing countries. The emergence of drug-resistant TB makes the condition worse and there is an urgent need of fast, highly sensitive diagnostic methods. This study was undertaken to evaluate the performance of GeneXpert® MTB/RIF assay and MTB culture for the detection of Mycobacterium tuberculosis (MTB) in sputum smear-negative pulmonary TB/drug-resistant tuberculosis (DR-TB) suspects. A total of 168 sputum smear-negative TB suspects were recruited for the study. Among the suspected TB cases, 52.98% were male and 47.02% were females with the mean age of 42 ± 17.6 years. All the sputum specimens collected from the study population were subjected to Ziehl-Neelsen (ZN) smear microscopy, GeneXpert MTB/RIF assay, and MTB culture. The results revealed that, out of 168 acid-fast bacilli (AFB)/ZN smear microscopy-negative sputum specimens, 48 (28.57%) and 58 (34.52%) were detected MTB positive by GeneXpert MTB/RIF assay and MTB culture, respectively, while 120 (71.43%) and 110 (65.48%) suspected TB cases were confirmed negative by GeneXpert MTB/RIF assay and MTB culture, respectively. The study concluded that GeneXpert assay was found to be a rapid and accurate tool for MTB detection in smear-negative sputum specimens. GeneXpert has advantage over ZN smear microscopy and MTB culture as it detects MTB and rifampicin resistance simultaneously within 2 h with minimal biohazards.

Keywords: AFB-negative smears; GeneXpert assay; MTB culture; pulmonary tuberculosis.

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Conflict of interest statement

Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figures

Figure 1.
Figure 1.
Different procedural steps in the Xpert MTB/RIF assay process.
Figure 2.
Figure 2.
Diagrammatic representation of study subjects among different age groups.
Figure 3.
Figure 3.
Frequency distribution graph showing the locality of participants in the study population.
See this image and copyright information in PMC

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