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Baseline predictors of sputum culture conversion in pulmonary tuberculosis: importance of cavities, smoking, time to detection and W-Beijing genotype
- Source :
- PLoS ONE, Vol 7, Iss 1, p e29588 (2012), PLoS One, PLoS ONE
- Publication Year :
- 2012
- Publisher :
- Public Library of Science (PLoS), 2012.
-
Abstract
- BackgroundTime 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.AimTo assess baseline predictors of failure of sputum culture conversion, within the first 2 months of antitubercular therapy, in participants with pulmonary tuberculosis.DesignBetween 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.Results113 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.ConclusionWe 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.
- Subjects :
- Bacterial Diseases
Male
Microbiological Techniques
Time Factors
Epidemiology
Cohort Studies
South Africa
0302 clinical medicine
Genotype
030212 general & internal medicine
Prospective cohort study
Vitamin A
Randomized Controlled Trials as Topic
0303 health sciences
Multidisciplinary
medicine.diagnostic_test
biology
Hazard ratio
Smoking
Drug Resistance, Microbial
Prognosis
Primary care
3. Good health
Zinc
Infectious Diseases
Disease Progression
Medicine
Female
medicine.symptom
Cohort study
Research Article
Adult
medicine.medical_specialty
Tuberculosis
Science
Sputum culture
Mycobacterium tuberculosis
03 medical and health sciences
Young Adult
Diagnostic Medicine
Internal medicine
medicine
Isoniazid
Humans
Tuberculosis diagnosis and management
Smoking habits
Biology
Tuberculosis, Pulmonary
Population Biology
030306 microbiology
business.industry
Sputum
Tropical Diseases (Non-Neglected)
biology.organism_classification
medicine.disease
Immunology
Dietary Supplements
Dental Pulp Cavity
business
Subjects
Details
- Language :
- English
- ISSN :
- 19326203
- Volume :
- 7
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- PLoS ONE
- Accession number :
- edsair.doi.dedup.....97d12f9bf68297efc44e37551ff98135