Detection of a historic reservoir of bedaquiline/clofazimine resistance-associated variants in Mycobacterium tuberculosis.

Background: Drug resistance in tuberculosis (TB) poses a major ongoing challenge to public health. The recent inclusion of bedaquiline into TB drug regimens has improved treatment outcomes, but this advance is threatened by the emergence of strains of Mycobacterium tuberculosis (Mtb) resistant to bedaquiline. Clinical bedaquiline resistance is most frequently conferred by off-target resistance-associated variants (RAVs) in the mmpR5 gene (Rv0678), the regulator of an efflux pump, which can also confer cross-resistance to clofazimine, another TB drug.

Point of care Xpert MTB/RIF versus smear microscopy for tuberculosis diagnosis in southern African primary care clinics: a multicentre economic evaluation.

Background: Rapid on-site diagnosis facilitates tuberculosis control. Performing Xpert MTB/RIF (Xpert) at point of care is feasible, even when performed by minimally trained health-care workers, and when compared with point-of-care smear microscopy, reduces time to diagnosis and pretreatment loss to follow-up. However, whether Xpert is cost-effective at point of care remains unclear.

Longitudinal assessment of health related quality of life of HIV infected patients treated for tuberculosis and HIV in a high burden setting.

Introduction: Assessment of patients receiving treatment for human immunodeficiency virus (HIV) and tuberculosis (TB) using a Health Related Quality of Life (HRQoL) instrument is important to get the subjective view of the patients' wellbeing.

Methods: We used the Functional Assessment of HIV Infection (FAHI) HRQoL instrument to collect perceived wellness information at baseline, month 3, 6 and 12 from patients enrolled in a pharmacokinetic study between March 2007 and April 2008. Composite domain scores at each time point and their relationship with the rate of adverse events (AEs) and serious adverse events were compared between treatment arms.

Population pharmacokinetic drug-drug interaction pooled analysis of existing data for rifabutin and HIV PIs.

Objectives: Extensive but fragmented data from existing studies were used to describe the drug-drug interaction between rifabutin and HIV PIs and predict doses achieving recommended therapeutic exposure for rifabutin in patients with HIV-associated TB, with concurrently administered PIs.

Methods: Individual-level data from 13 published studies were pooled and a population analysis approach was used to develop a pharmacokinetic model for rifabutin, its main active metabolite 25-O-desacetyl rifabutin (des-rifabutin) and drug-drug interaction with PIs in healthy volunteers and patients who had HIV and TB (TB/HIV).

Results: Key parameters of rifabutin affected by drug-drug interaction in TB/HIV were clearance to routes other than des-rifabutin (reduced by 76%-100%), formation of the metabolite (increased by 224% in patients), volume of distribution (increased by 606%) and distribution to the peripheral compartment (reduced by 47%).

Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing.

Background: The commercially available urine LAM strip test, a point-of-care tuberculosis (TB) assay, requires evaluation in a primary care setting where it is most needed. There is currently inadequate data to guide implementation in TB and HIV-endemic settings.

Methods: Adult HIV-infected outpatients with suspected pulmonary TB able to self-expectorate sputum from four primary clinics in South Africa, Zambia and Tanzania underwent diagnostic evaluation [sputum smear microscopy, Xpert-MTB/RIF, and culture (reference standard)] as part of a prospective parent study.

Psychological distress and its relationship with non-adherence to TB treatment: a multicentre study.

Background: The successful cure of tuberculosis (TB) is dependent on adherence to treatment. Various factors influence adherence, however, few are easily modifiable. There are limited data regarding correlates of psychological distress and their association with non-adherence to anti-TB treatment.

Impact of tuberculosis treatment and antiretroviral therapy on serial RD-1-specific quantitative T-cell readouts (QuantiFERON-TB Gold In-Tube), and relationship to treatment-related outcomes and bacterial burden.

Background: The impact of anti-tuberculosis treatment with and without antiretroviral therapy (ART) on standardized interferon gamma release assay (IGRA) readouts has been studied inadequately in high-burden countries.

Methods: The QuantiFERON-TB Gold In-Tube (QFT-GIT) test was used to evaluate interferon gamma (IFN-γ) responses longitudinally (0, 3, 6, and 12 months post initiation of tuberculosis (TB)-HIV co-treatment or ART alone) in 82 HIV-infected patients.

Results: Of the 65 evaluable participants, 30 were co-infected on ART, 17 were co-infected but not on ART, and 18 were HIV-infected alone and on ART.

Early versus delayed initiation of highly active antiretroviral therapy for HIV-positive adults with newly diagnosed pulmonary tuberculosis (TB-HAART): a prospective, international, randomised, placebo-controlled trial.

Background: WHO guidelines recommend early initiation of antiretroviral therapy (ART) irrespective of CD4 cell count for all patients with tuberculosis who also have HIV, but evidence supporting this approach is poor quality. We assessed the effect of timing of ART initiation on tuberculosis treatment outcomes for HIV-positive patients with CD4 counts of 220 cells per μL or more.

Methods: We did this randomised, placebo-controlled trial between Jan 1, 2008, and April 31, 2013 at 26 treatment centres in South Africa, Tanzania, Uganda, and Zambia.

Whole-genome sequencing to establish relapse or re-infection with Mycobacterium tuberculosis: a retrospective observational study.

Background: Recurrence of tuberculosis after treatment makes management difficult and is a key factor for determining treatment efficacy. Two processes can cause recurrence: relapse of the primary infection or re-infection with an exogenous strain. Although re-infection can and does occur, its importance to tuberculosis epidemiology and its biological basis is still debated.

Feasibility, accuracy, and clinical effect of point-of-care Xpert MTB/RIF testing for tuberculosis in primary-care settings in Africa: a multicentre, randomised, controlled trial.

Background: The Xpert MTB/RIF test for tuberculosis is being rolled out in many countries, but evidence is lacking regarding its implementation outside laboratories, ability to inform same-day treatment decisions at the point of care, and clinical effect on tuberculosis-related morbidity. We aimed to assess the feasibility, accuracy, and clinical effect of point-of-care Xpert MTB/RIF testing at primary-care health-care facilities in southern Africa.

Methods: In this pragmatic, randomised, parallel-group, multicentre trial, we recruited adults with symptoms suggestive of active tuberculosis from five primary-care health-care facilities in South Africa, Zimbabwe, Zambia, and Tanzania.

Proteome analysis of the plasma membrane of Mycobacterium tuberculosis.

The plasma membrane of Mycobacterium tuberculosis is likely to contain proteins that could serve as novel drug targets, diagnostic probes or even components of a vaccine against tuberculosis. With this in mind, we have undertaken proteome analysis of the membrane of M. tuberculosis H37Rv.

Does resistance to pyrazinamide accurately indicate the presence of Mycobacterium bovis?

Mycobacterium bovis is best identified by screening those isolates of the Mycobacterium tuberculosis complex that have any pyrazinamide (PZA) resistance, using a confirmatory test such as spoligotyping, biochemical testing, or genomic deletion analysis. The sensitivity for detection of M. bovis is lowered to 82% when only PZA-monoresistant isolates are screened.