Baseline Predictors of Sputum Culture Conversion in Pulmonary Tuberculosis: Importance of Cavities, Smoking, Time to Detection and W-Beijing Genotype

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dc.contributor.authorVisser, Marianne Een_ZA
dc.contributor.authorStead, Michael Cen_ZA
dc.contributor.authorWalzl, Gerharden_ZA
dc.contributor.authorWarren, Roben_ZA
dc.contributor.authorSchomaker, Michaelen_ZA
dc.contributor.authorGrewal, Harleen M Sen_ZA
dc.contributor.authorSwart, Elizabeth Cen_ZA
dc.contributor.authorMaartens, Garyen_ZA
dc.date.accessioned2015-12-28T06:51:43Z
dc.date.available2015-12-28T06:51:43Z
dc.date.issued2012en_ZA
dc.description.abstractBACKGROUND: Time to detection (TTD) on automated liquid mycobacterial cultures is an emerging biomarker of tuberculosis outcomes. The M. tuberculosis W-Beijing genotype is spreading globally, indicating a selective advantage. There is a paucity of data on the association between baseline TTD and W-Beijing genotype and tuberculosis outcomes. Aim To assess baseline predictors of failure of sputum culture conversion, within the first 2 months of antitubercular therapy, in participants with pulmonary tuberculosis. Design Between May 2005 and August 2008 we conducted a prospective cohort study of time to sputum culture conversion in ambulatory participants with first episodes of smear and culture positive pulmonary tuberculosis attending two primary care clinics in Cape Town, South Africa. Rifampicin resistance (diagnosed on phenotypic susceptibility testing) was an exclusion criterion. Sputum was collected weekly for 8 weeks for mycobacterial culture on liquid media (BACTEC MGIT 960). Due to missing data, multiple imputation was performed. Time to sputum culture conversion was analysed using a Cox-proportional hazards model. Bayesian model averaging determined the posterior effect probability for each variable. RESULTS: 113 participants were enrolled (30.1% female, 10.5% HIV-infected, 44.2% W-Beijing genotype, and 89% cavities). On Kaplan Meier analysis 50.4% of participants underwent sputum culture conversion by 8 weeks. The following baseline factors were associated with slower sputum culture conversion: TTD (adjusted hazard ratio (aHR) = 1.11, 95% CI 1.02; 1.2), lung cavities (aHR = 0.13, 95% CI 0.02; 0.95), ever smoking (aHR = 0.32, 95% CI 0.1; 1.02) and the W-Beijing genotype (aHR = 0.51, 95% CI 0.25; 1.07). On Bayesian model averaging, posterior probability effects were strong for TTD, lung cavitation and smoking and moderate for W-Beijing genotype. CONCLUSION: We found that baseline TTD, smoking, cavities and W-Beijing genotype were associated with delayed 2 month sputum culture. Larger studies are needed to confirm the relationship between the W-Beijing genotype and sputum culture conversion.en_ZA
dc.identifier.apacitationVisser, M. E., Stead, M. C., Walzl, G., Warren, R., Schomaker, M., Grewal, H. M. S., ... Maartens, G. (2012). Baseline Predictors of Sputum Culture Conversion in Pulmonary Tuberculosis: Importance of Cavities, Smoking, Time to Detection and W-Beijing Genotype. <i>PLoS One</i>, http://hdl.handle.net/11427/16070en_ZA
dc.identifier.chicagocitationVisser, Marianne E, Michael C Stead, Gerhard Walzl, Rob Warren, Michael Schomaker, Harleen M S Grewal, Elizabeth C Swart, and Gary Maartens "Baseline Predictors of Sputum Culture Conversion in Pulmonary Tuberculosis: Importance of Cavities, Smoking, Time to Detection and W-Beijing Genotype." <i>PLoS One</i> (2012) http://hdl.handle.net/11427/16070en_ZA
dc.identifier.citationVisser, M. E., Stead, M. C., Walzl, G., Warren, R., Schomaker, M., Grewal, H. M., ... & Maartens, G. (2012). Baseline predictors of sputum culture conversion in pulmonary tuberculosis: importance of cavities, smoking, time to detection and W-Beijing genotype. PloS one, 7(1), e29588. doi:10.1371/journal.pone.0029588en_ZA
dc.identifier.ris TY - Journal Article AU - Visser, Marianne E AU - Stead, Michael C AU - Walzl, Gerhard AU - Warren, Rob AU - Schomaker, Michael AU - Grewal, Harleen M S AU - Swart, Elizabeth C AU - Maartens, Gary AB - BACKGROUND: Time to detection (TTD) on automated liquid mycobacterial cultures is an emerging biomarker of tuberculosis outcomes. The M. tuberculosis W-Beijing genotype is spreading globally, indicating a selective advantage. There is a paucity of data on the association between baseline TTD and W-Beijing genotype and tuberculosis outcomes. Aim To assess baseline predictors of failure of sputum culture conversion, within the first 2 months of antitubercular therapy, in participants with pulmonary tuberculosis. Design Between May 2005 and August 2008 we conducted a prospective cohort study of time to sputum culture conversion in ambulatory participants with first episodes of smear and culture positive pulmonary tuberculosis attending two primary care clinics in Cape Town, South Africa. Rifampicin resistance (diagnosed on phenotypic susceptibility testing) was an exclusion criterion. Sputum was collected weekly for 8 weeks for mycobacterial culture on liquid media (BACTEC MGIT 960). Due to missing data, multiple imputation was performed. Time to sputum culture conversion was analysed using a Cox-proportional hazards model. Bayesian model averaging determined the posterior effect probability for each variable. RESULTS: 113 participants were enrolled (30.1% female, 10.5% HIV-infected, 44.2% W-Beijing genotype, and 89% cavities). On Kaplan Meier analysis 50.4% of participants underwent sputum culture conversion by 8 weeks. The following baseline factors were associated with slower sputum culture conversion: TTD (adjusted hazard ratio (aHR) = 1.11, 95% CI 1.02; 1.2), lung cavities (aHR = 0.13, 95% CI 0.02; 0.95), ever smoking (aHR = 0.32, 95% CI 0.1; 1.02) and the W-Beijing genotype (aHR = 0.51, 95% CI 0.25; 1.07). On Bayesian model averaging, posterior probability effects were strong for TTD, lung cavitation and smoking and moderate for W-Beijing genotype. CONCLUSION: We found that baseline TTD, smoking, cavities and W-Beijing genotype were associated with delayed 2 month sputum culture. Larger studies are needed to confirm the relationship between the W-Beijing genotype and sputum culture conversion. DA - 2012 DB - OpenUCT DO - 10.1371/journal.pone.0029588 DP - University of Cape Town J1 - PLoS One LK - https://open.uct.ac.za PB - University of Cape Town PY - 2012 T1 - Baseline Predictors of Sputum Culture Conversion in Pulmonary Tuberculosis: Importance of Cavities, Smoking, Time to Detection and W-Beijing Genotype TI - Baseline Predictors of Sputum Culture Conversion in Pulmonary Tuberculosis: Importance of Cavities, Smoking, Time to Detection and W-Beijing Genotype UR - http://hdl.handle.net/11427/16070 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/16070
dc.identifier.urihttp://dx.doi.org/10.1371/journal.pone.0029588
dc.identifier.vancouvercitationVisser ME, Stead MC, Walzl G, Warren R, Schomaker M, Grewal HMS, et al. Baseline Predictors of Sputum Culture Conversion in Pulmonary Tuberculosis: Importance of Cavities, Smoking, Time to Detection and W-Beijing Genotype. PLoS One. 2012; http://hdl.handle.net/11427/16070.en_ZA
dc.language.isoengen_ZA
dc.publisherPublic Library of Scienceen_ZA
dc.publisher.departmentDivision of Medical Biochemistryen_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© 2012 Visser et alen_ZA
dc.rights.urihttp://creativecommons.org/licenses/by/4.0en_ZA
dc.sourcePLoS Oneen_ZA
dc.source.urihttp://journals.plos.org/plosoneen_ZA
dc.subject.otherSputumen_ZA
dc.subject.otherTuberculosisen_ZA
dc.subject.otherMycobacterium tuberculosisen_ZA
dc.subject.otherSmoking habitsen_ZA
dc.subject.otherTuberculosis diagnosis and managementen_ZA
dc.subject.otherIsoniaziden_ZA
dc.subject.otherPrimary careen_ZA
dc.subject.otherSouth Africaen_ZA
dc.titleBaseline Predictors of Sputum Culture Conversion in Pulmonary Tuberculosis: Importance of Cavities, Smoking, Time to Detection and W-Beijing Genotypeen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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