Woldie, Biruk Mekonnen (2017) Performance Evaluation of MDR-TB Color Plate Test for Rapid Detection of Mycobacterium Tuberculosis and Multidrug-resistant Tuberculosis in Resource-limited Setting, Addis Ababa, Ethiopia. Masters thesis, Addis Ababa University.
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Abstract
Background: Tuberculosis (TB) is a top global public health concern and its controlling program is chiefly hampered by diagnostic difficulties. Timely TB diagnosis and detection of drug-resistant TB has a key significance for both patient management and the disease control. However, the commercially existing diagnostic tools are slow and unaffordable for resourcelimited settings. Objective: The current study was aimed to evaluate the performance of MDR-TB color plate test (color plate test) for rapid concurrent detection of Mycobacterium tuberculosis (MTB) and multidrug-resistant TB (MDR-TB) directly from sputum specimens. Materials and Methods: A cross-sectional, hospital-based diagnostic test evaluation study was conducted from March 2016 to February 2017 at All Africa Leprosy, Tuberculosis and Rehabilitation Training Center (ALERT) hospital and St. Peter’s TB referral hospital in Addis Ababa, Ethiopia. The performance of the color plate test was prospectively compared to the conventional Lӧwenstein-Jensen (LJ) culture and LJ indirect proportional drug susceptibility test (DST), and the molecular GeneXpert MTB/RIF® assay. A paired morning expectorated sputum samples were collected from 147 MDR-TB suspected patients using a convenience sampling technique in both hospitals. One of the two sputum samples is used for diagnosis purpose was tested directly by GeneXpert assay at each respective hospital’s laboratory and internally validated. But, the other sputa were refrigerated (4-80C) and transported to the Armauer Hansen Research Institute (AHRI) TB laboratory where the color plate test and the conventional LJ culture and DST were conducted. Data were analyzed using SPSS version 20, and kappa statistic was applied to test agreement between results of the three assays. Result: Of the 147 sputa, 137 (93.2%) sputa produced interpretable MTB detection results for all the three assays and were included in the analysis. Compared to the conventional LJ culture, color plate test was 93.6% sensitive and 98.3% specific while GeneXpert assay was 96.2% sensitive and 79.7% specific. Moreover, the color plate test had showed a strong agreement with both the conventional LJ culture (95.62%, kappa 0.9114) and GeneXpert assay (89.05%, kappa 0.7756) for the detection of MTB. Moreover, all conventional LJ xv culture positives, 78 isolates were further subjected to conventional DST, and valid results obtained by color plate test and GeneXpert assay were 70 and 72 isolates respectively. The color plate test demonstrated sensitivity of 91.3% and 93.6% specific for the detection of isoniazid resistant MTB isolates with strong agreements (kappa 0.8399). However, the accuracy for detection of rifampicin resistance was suboptimal with low agreement (kappa value of 0.08 and concordance 39%). The color plate test was also in low agreement with the GeneXpert assay (38.57%, kappa 0.0773) for detection of RMP drug resistance. In the present study, the results of color plate test can be obtained in a median time of 13 days while the conventional indirect DST method requires an average of 50 days. Besides, the color plate test is simple to use and the cost per test result also minimal relatively. Conclusion: In this study, the color plate test was found to be a good alternative method for screening of TB and selective drug resistant-TB in a timely and affordable way in resourcelimited setting despite limitations of the test need to be addressed before test approvals.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Color plate test, Conventional LJ culture, Diagnostic performance, GeneXpert assay, indirect proportional DST, Multidrug-resistant tuberculosis, Tuberculosis |
| Subjects: | Q Science > Q Science (General) Q Science > QR Microbiology |
| Divisions: | Africana |
| Depositing User: | Vincent Mpoza |
| Date Deposited: | 04 Oct 2018 08:40 |
| Last Modified: | 04 Oct 2018 08:40 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/6690 |
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