Performance of Xpert® MTB/RIF among tuberculosis outpatients in Lilongwe, Malawi
African Journal of Laboratory Medicine
| Field | Value | |
| Title | Performance of Xpert® MTB/RIF among tuberculosis outpatients in Lilongwe, Malawi | |
| Creator | Chikaonda, Tarsizio Nguluwe, Nelson Barnett, Brian Gokhale, Runa H. Krysiak, Robert Thengolose, Isaac Rosenberg, Nora E. Stanley, Christopher Mpunga, James Hoffman, Irving F. Hosseinipour, Mina Scott, Lesley Stevens, Wendy | |
| Description | Background: Xpert® MTB/RIF is a molecular test for the detection of Mycobacterium tuberculosis and rifampicin resistance. It is considered to be a great advance over smear microscopy and culture. However, there is very little information regarding the performance characteristics of Xpert MTB/RIF in Malawi.Objective: We aimed to evaluate the performance of Xpert MTB/RIF in a Malawian setting.Methods: Stored sputum pellets were processed on Xpert MTB/RIF between June 2012 andMay 2014. Results were compared to mycobacteria growth indicator tube and Löwenstein-Jensen cultures, LED fluorescent microscopy and GenoType® MTBDRplus assay. Rifampicinresistance was confirmed by DNA sequencing.Results: Of the 348 specimens with valid Xpert MTB/RIF results, 129/348 (37%) were smearpositive and 198/348 (57%) were culture-positive. Xpert MTB/RIF demonstrated a sensitivity of 93.8% (95% CI 89.4% – 96.8%) and specificity of 97.4% (95% CI 93.5% – 99.3%), with a positive predictive value of 97.8% (95% CI 94.6% – 99.4%) and a negative predictive value of 92.6% (95% CI 87.4% – 96.1%). Xpert MTB/RIF correctly identified 185/186 (99.5%) rifampicin sensitive and 2/2 (100%) rifampicin-resistant M. tuberculosis strains. Mutations were notdetected by sequencing in one isolate which was rifampicin resistant on Xpert MTB/RIF butsensitive on MTBDRplus. Four non-tuberculous mycobacteria grew from four smear-negativespecimens, namely, M. avium (n = 1) and M. intracellulare (n = 3). No cross-reactivity wasobserved with any of the non-tuberculous mycobacteria when using Xpert MTB/RIF.Conclusion: When fully implemented, Xpert MTB/RIF may have an impact on patient care inMalawi. The increased diagnostic yield of Xpert MTB/RIF over smear microscopy can increaselaboratory-confirmed tuberculosis detection and ensure that treatment is given to appropriateindividuals or groups. | |
| Publisher | AOSIS | |
| Date | 2017-03-31 | |
| Identifier | 10.4102/ajlm.v6i2.464 | |
| Source | African Journal of Laboratory Medicine; Vol 6, No 2 (2017); 7 pages 2225-2010 2225-2002 | |
| Language | eng | |
| Relation |
The following web links (URLs) may trigger a file download or direct you to an alternative webpage to gain access to a publication file format of the published article:
https://ajlmonline.org/index.php/ajlm/article/view/464/800
https://ajlmonline.org/index.php/ajlm/article/view/464/799
https://ajlmonline.org/index.php/ajlm/article/view/464/801
https://ajlmonline.org/index.php/ajlm/article/view/464/786
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