Screening for HIV-associated tuberculosis and rifampicin resistance before antiretroviral therapy using the Xpert MTB/RIF assay: a prospective study

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dc.contributor.authorLawn, Stephen Den_ZA
dc.contributor.authorBrooks, Sophie Ven_ZA
dc.contributor.authorKranzer, Katharinaen_ZA
dc.contributor.authorNicol, Mark Pen_ZA
dc.contributor.authorWhitelaw, Andrewen_ZA
dc.contributor.authorVogt, Monicaen_ZA
dc.contributor.authorBekker, Linda-Gailen_ZA
dc.contributor.authorWood, Robinen_ZA
dc.date.accessioned2016-01-11T06:50:53Z
dc.date.available2016-01-11T06:50:53Z
dc.date.issued2011en_ZA
dc.description.abstractBackground: The World Health Organization has endorsed the Xpert MTB/RIF assay for investigation of patients suspected of having tuberculosis (TB). However, its utility for routine TB screening and detection of rifampicin resistance among HIV-infected patients with advanced immunodeficiency enrolling in antiretroviral therapy (ART) services is unknown. Methods and Findings: Consecutive adult HIV-infected patients with no current TB diagnosis enrolling in an ART clinic in a South African township were recruited regardless of symptoms. They were clinically characterised and invited to provide two sputum samples at a single visit. The accuracy of the Xpert MTB/RIF assay for diagnosing TB and drug resistance was assessed in comparison with other tests, including fluorescence smear microscopy and automated liquid culture (gold standard) and drug susceptibility testing. Of 515 patients enrolled, 468 patients (median CD4 cell count, 171 cells/µl; interquartile range, 102–236) produced at least one sputum sample, yielding complete sets of results from 839 samples. Mycobacterium tuberculosis was cultured from 81 patients (TB prevalence, 17.3%). The overall sensitivity of the Xpert MTB/RIF assay for culture-positive TB was 73.3% (specificity, 99.2%) compared to 28.0% (specificity, 100%) using smear microscopy. All smear-positive, culture-positive disease was detected by Xpert MTB/RIF from a single sample (sensitivity, 100%), whereas the sensitivity for smear-negative, culture-positive TB was 43.4% from one sputum sample and 62.3% from two samples. Xpert correctly identified rifampicin resistance in all four cases of multidrug-resistant TB but incorrectly identified resistance in three other patients whose disease was confirmed to be drug sensitive by gene sequencing (specificity, 94.1%; positive predictive value, 57%). Conclusions: In this population of individuals at high risk of TB, intensive screening using the Xpert MTB/RIF assay increased case detection by 45% compared with smear microscopy, strongly supporting replacement of microscopy for this indication. However, despite the ability of the assay to rapidly detect rifampicin-resistant disease, the specificity for drug-resistant TB was sub-optimal.en_ZA
dc.identifier.apacitationLawn, S. D., Brooks, S. V., Kranzer, K., Nicol, M. P., Whitelaw, A., Vogt, M., ... Wood, R. (2011). Screening for HIV-associated tuberculosis and rifampicin resistance before antiretroviral therapy using the Xpert MTB/RIF assay: a prospective study. <i>PLOS Medicince</i>, http://hdl.handle.net/11427/16236en_ZA
dc.identifier.chicagocitationLawn, Stephen D, Sophie V Brooks, Katharina Kranzer, Mark P Nicol, Andrew Whitelaw, Monica Vogt, Linda-Gail Bekker, and Robin Wood "Screening for HIV-associated tuberculosis and rifampicin resistance before antiretroviral therapy using the Xpert MTB/RIF assay: a prospective study." <i>PLOS Medicince</i> (2011) http://hdl.handle.net/11427/16236en_ZA
dc.identifier.citationLawn, S. D., Brooks, S. V., Kranzer, K., Nicol, M. P., Whitelaw, A., Vogt, M., ... & Wood, R. (2011). Screening for HIV-associated tuberculosis and rifampicin resistance before antiretroviral therapy using the Xpert MTB/RIF assay: a prospective study. PLoS medicine, 8(7), 910. doi:10.1371/journal.pmed.1001067en_ZA
dc.identifier.ris TY - Journal Article AU - Lawn, Stephen D AU - Brooks, Sophie V AU - Kranzer, Katharina AU - Nicol, Mark P AU - Whitelaw, Andrew AU - Vogt, Monica AU - Bekker, Linda-Gail AU - Wood, Robin AB - Background: The World Health Organization has endorsed the Xpert MTB/RIF assay for investigation of patients suspected of having tuberculosis (TB). However, its utility for routine TB screening and detection of rifampicin resistance among HIV-infected patients with advanced immunodeficiency enrolling in antiretroviral therapy (ART) services is unknown. Methods and Findings: Consecutive adult HIV-infected patients with no current TB diagnosis enrolling in an ART clinic in a South African township were recruited regardless of symptoms. They were clinically characterised and invited to provide two sputum samples at a single visit. The accuracy of the Xpert MTB/RIF assay for diagnosing TB and drug resistance was assessed in comparison with other tests, including fluorescence smear microscopy and automated liquid culture (gold standard) and drug susceptibility testing. Of 515 patients enrolled, 468 patients (median CD4 cell count, 171 cells/µl; interquartile range, 102–236) produced at least one sputum sample, yielding complete sets of results from 839 samples. Mycobacterium tuberculosis was cultured from 81 patients (TB prevalence, 17.3%). The overall sensitivity of the Xpert MTB/RIF assay for culture-positive TB was 73.3% (specificity, 99.2%) compared to 28.0% (specificity, 100%) using smear microscopy. All smear-positive, culture-positive disease was detected by Xpert MTB/RIF from a single sample (sensitivity, 100%), whereas the sensitivity for smear-negative, culture-positive TB was 43.4% from one sputum sample and 62.3% from two samples. Xpert correctly identified rifampicin resistance in all four cases of multidrug-resistant TB but incorrectly identified resistance in three other patients whose disease was confirmed to be drug sensitive by gene sequencing (specificity, 94.1%; positive predictive value, 57%). Conclusions: In this population of individuals at high risk of TB, intensive screening using the Xpert MTB/RIF assay increased case detection by 45% compared with smear microscopy, strongly supporting replacement of microscopy for this indication. However, despite the ability of the assay to rapidly detect rifampicin-resistant disease, the specificity for drug-resistant TB was sub-optimal. DA - 2011 DB - OpenUCT DO - 10.1371/journal.pmed.1001067 DP - University of Cape Town J1 - PLOS Medicince LK - https://open.uct.ac.za PB - University of Cape Town PY - 2011 T1 - Screening for HIV-associated tuberculosis and rifampicin resistance before antiretroviral therapy using the Xpert MTB/RIF assay: a prospective study TI - Screening for HIV-associated tuberculosis and rifampicin resistance before antiretroviral therapy using the Xpert MTB/RIF assay: a prospective study UR - http://hdl.handle.net/11427/16236 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/16236
dc.identifier.urihttp://dx.doi.org/10.1371/journal.pmed.1001067
dc.identifier.vancouvercitationLawn SD, Brooks SV, Kranzer K, Nicol MP, Whitelaw A, Vogt M, et al. Screening for HIV-associated tuberculosis and rifampicin resistance before antiretroviral therapy using the Xpert MTB/RIF assay: a prospective study. PLOS Medicince. 2011; http://hdl.handle.net/11427/16236.en_ZA
dc.language.isoengen_ZA
dc.publisherPublic Library of Scienceen_ZA
dc.publisher.departmentDesmond Tutu HIV Centreen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.rightsThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.en_ZA
dc.rights.holder© 2011 Lawn et alen_ZA
dc.rights.urihttp://creativecommons.org/licenses/by/4.0en_ZA
dc.sourcePLOS Medicinceen_ZA
dc.source.urihttp://journals.plos.org/plosmedicineen_ZA
dc.subject.otherTuberculosisen_ZA
dc.subject.otherMycobacterium tuberculosisen_ZA
dc.subject.otherTuberculosis diagnosis and managementen_ZA
dc.subject.otherSputumen_ZA
dc.subject.otherMulti-drug-resistant tuberculosisen_ZA
dc.subject.otherDiagnostic medicineen_ZA
dc.subject.otherCoughingen_ZA
dc.subject.otherExtensively drug-resistant tuberculosisen_ZA
dc.titleScreening for HIV-associated tuberculosis and rifampicin resistance before antiretroviral therapy using the Xpert MTB/RIF assay: a prospective studyen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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