Bacterial loads measured by the Xpert MTB/RIF assay as markers of culture conversion and bacteriological cure in pulmonary TB

dc.contributor.authorShenai, Shubhadaen_ZA
dc.contributor.authorRonache, Katharinaen_ZA
dc.contributor.authorMalherbe, Stefanusen_ZA
dc.contributor.authorStanley, Kimen_ZA
dc.contributor.authorKriel, Magdalenaen_ZA
dc.contributor.authorWinter, Jillen_ZA
dc.contributor.authorPeppard, Thomasen_ZA
dc.contributor.authorBarry, Charles E.en_ZA
dc.contributor.authorWang, Jingen_ZA
dc.contributor.authorDodd, Lori E.en_ZA
dc.contributor.authorVia, Laura E.en_ZA
dc.contributor.authorBarry, Clifton E. 3rden_ZA
dc.contributor.authorWalzl, Gerharden_ZA
dc.contributor.authorAlland, Daviden_ZA
dc.date.accessioned2017-09-27T14:26:37Z
dc.date.available2017-09-27T14:26:37Z
dc.date.issued2016
dc.descriptionCITATION: Shenai, S., et al. 2016. Bacterial loads measured by the Xpert MTB/RIF assay as markers of culture conversion and bacteriological cure in pulmonary TB. PLoS ONE, 11(8):e0160062, doi:10.1371/journal.pone.0160062.
dc.descriptionThe original publication is available at http://journals.plos.org/plosone
dc.description.abstractIntroduction: Biomarkers are needed to monitor tuberculosis (TB) treatment and predict treatment outcomes. We evaluated the Xpert MTB/RIF (Xpert) assay as a biomarker for TB treatment during and at the end of the 24 weeks therapy. Methods: Sputum from 108 HIV-negative, culture-positive pulmonary TB patients was analyzed using Xpert at time points before and during anti-TB therapy. Results were compared against culture. Direct Xpert cycle-threshold (Ct), a change in the Ct (delta Ct), or a novel “percent closing of baseline Ct deficit” (percent closing) were evaluated as classifiers of same-day and end-of-treatment culture and therapeutic outcomes. Results: Xpert was positive in 29/95 (30.5%) of subjects at week 24; and positive one year after treatment in 8/64 (12.5%) successfully-treated patients who remained free of tuberculosis. We identified a relationship between initial bacterial load measured by baseline Xpert Ct and time to culture conversion (hazard ratio 1.06, p = 0.0023), and to the likelihood of being among the 8 treatment failures at week 24 (AUC = 72.8%). Xpert Ct was even more strongly associated with culture conversion on the day the test was performed with AUCs 96.7%, 99.2%, 86.0% and 90.2%, at Day 7, Week 4, 8 and 24, respectively. Compared to baseline Ct measures alone, a combined measure of baseline Ct plus either Delta Ct or percent closing improved the classification of treatment failure status to a 75% sensitivity and 88.9% specificity. Conclusions: Genome loads measured by Xpert provide a potentially-useful biomarker for classifying same day culture status and predicting response to therapy.en_ZA
dc.description.urihttp://journals.plos.org/plosone/article?id=10.1371/journal.pone.0160062
dc.description.versionPublisher's version
dc.format.extent13 pages
dc.identifier.citationShenai, S., et al. 2016. Bacterial loads measured by the Xpert MTB/RIF assay as markers of culture conversion and bacteriological cure in pulmonary TB. PLoS ONE, 11(8):e0160062, doi:10.1371/journal.pone.0160062
dc.identifier.issn1932-6203 (online)
dc.identifier.otherdoi:10.1371/journal.pone.0160062
dc.identifier.urihttp://hdl.handle.net/10019.1/102284
dc.language.isoen_ZAen_ZA
dc.publisherPublic Library of Science
dc.rights.holderAuthors retain copyright
dc.subjectTuberculosis -- Treatment -- Measurementen_ZA
dc.subjectBiochemical markersen_ZA
dc.subjectXpert MTB/RIF assayen_ZA
dc.subjectBacteriology -- Cultures and culture mediaen_ZA
dc.titleBacterial loads measured by the Xpert MTB/RIF assay as markers of culture conversion and bacteriological cure in pulmonary TBen_ZA
dc.typeArticleen_ZA
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