Evaluation of SO-DMT Assay in Sputum Specimens from Hawassa Town, Ethiopia

Abiy, Aklilu (2015) Evaluation of SO-DMT Assay in Sputum Specimens from Hawassa Town, Ethiopia. Masters thesis, Addis Ababa University.

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The lack of simple, accurate and rapid diagnostics is a major hindrance to TB control efforts, especially in developing countries including Ethiopia where sputum smear microscopy is the mainstay of diagnosis. Therefore, the need for rapid and accurate diagnostics is crucial. The new Speed-oligo Direct Mycobacterium tuberculosis (SODMT) assay is a novel assay which is based on multiplex PCR combined with dipstick hybridization that allows amplification of 16S rRNA and IS6110 to detect genus Mycobacterium and Mycobacterium tuberculosis complex from respiratory samples, respectively. The objective of the study is to evaluate the performance of the new SODMT assay in relation to conventional microscopic and culture methods and Xpert MTB/RIF assay for the detection of M. tuberculosis complex directly from sputum samples in SNNPR, Ethiopia. A total of 145 sputum samples were included in the evaluation of SO-DMT assay. One sample per patient was decontaminated by NALCNaOH method to perform Ziehl-Neelsen stain, culture and SO-DMT assay. One hundred nine of the sputum specimens were also tested by Xpert MTB/RIF assay. The sensitivity, specificity, positive predictive value and negative predictive value of SO-DMT assay for detection of MTBC were 96%, 97.8%, 99% and 91.7%, respectively with reference to culture. The corresponding values after resolution of discrepant results with culture and clinical data were 96% (100% in smear-positives and 89.5% in smear-negatives), 100%, 100% and 91.7% (100% in smear-positives and 90.5% in smear-negatives), respectively. The concordance between SO-DMT assay results and culture had a Cohen’s kappa index of 0.921 (SE, 0.035), indicating excellent concordance. The sensitivity of both SO-DMT and Xpert MTB/RIF assays was 94.8% (100% in smear-positives and 87.1% in smearnegatives). The specificity of SO-DMT and Xpert MTB/RIF assays were 100% and 93.8% (100% in smear-positives and 93% in smear-negatives), respectively. Therefore, SO-DMT has a good sensitivity and specificity in smear-positive and smear negative specimens. It's use can avoid the need to wait for culture results. This assay might be a good alternative to real-time PCR assays for laboratories not equipped with real-time PCR instruments.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Löwenstein-Jensen culture, SO-DMT assay, Xpert MTB/RIF assay, ZiehlNeelsen staining
Subjects: Q Science > QH Natural history > QH301 Biology
Q Science > QR Microbiology
Q Science > QR Microbiology > QR180 Immunology
R Medicine > RA Public aspects of medicine > RA0421 Public health. Hygiene. Preventive Medicine
Divisions: Africana
Depositing User: Selom Ghislain
Date Deposited: 18 Jun 2018 11:44
Last Modified: 18 Jun 2018 11:44
URI: http://thesisbank.jhia.ac.ke/id/eprint/4315

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