Mycobacterium Tuberculosis Complex Indicates Evolutionarily Recent Global Dissemination.

The lack of simple, accurate and rapid diagnostics is a major hindrance to TB controlrnefforts, especially in developing countries including Ethiopia where sputum smearrnmicroscopy is the mainstay of diagnosis. Therefore, the need for rapid and accuraterndiagnostics is crucial. The new Speed-oligo Direct Mycobacterium tuberculosis (SODMT)rnassay is a novel assay which is based on multiplex PCR combined with dipstickrnhybridization that allows amplification of 16S rRNA and IS6110 to detect genusrnMycobacterium and Mycobacterium tuberculosis complex from respiratory samples,rnrespectively. The objective of the study is to evaluate the performance of the new SODMTrnassay in relation to conventional microscopic and culture methods and XpertrnMTB/RIF assay for the detection of M. tuberculosis complex directly from sputumrnsamples in SNNPR, Ethiopia. A total of 145 sputum samples were included in thernevaluation of SO-DMT assay. One sample per patient was decontaminated by NALCNaOHrnmethod to perform Ziehl-Neelsen stain, culture and SO-DMT assay. One hundredrnnine of the sputum specimens were also tested by Xpert MTB/RIF assay. The sensitivity,rnspecificity, positive predictive value and negative predictive value of SO-DMT assay forrndetection of MTBC were 96%, 97.8%, 99% and 91.7%, respectively with reference tornculture. The corresponding values after resolution of discrepant results with culture andrnclinical data were 96% (100% in smear-positives and 89.5% in smear-negatives), 100%,rn100% and 91.7% (100% in smear-positives and 90.5% in smear-negatives), respectively.rnThe concordance between SO-DMT assay results and culture had a Cohen’s kappa indexrnof 0.921 (SE, 0.035), indicating excellent concordance. The sensitivity of both SO-DMTrnand Xpert MTB/RIF assays was 94.8% (100% in smear-positives and 87.1% in smearnegatives).rnThe specificity of SO-DMT and Xpert MTB/RIF assays were 100% andrn93.8% (100% in smear-positives and 93% in smear-negatives), respectively. Therefore,rnSO-DMT has a good sensitivity and specificity in smear-positive and smear negativernspecimens. It's use can avoid the need to wait for culture results. This assay might be arngood alternative to real-time PCR assays for laboratories not equipped with real-timernPCR instruments.rnKey words: Löwenstein-Jensen culture, SO-DMT assay, Xpert MTB/RIF assay, Ziehl-rnNeelsen staining

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