Browsing by Author "Kaplan, Gilla"

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    Correlation of rpoB mutations with minimal inhibitory concentration of rifampin and rifabutin in Mycobacterium tuberculosis in an HIV/AIDS endemic setting, South Africa
    (Frontiers, 2016-12-05) Rukasha, Ivy; Said, Halima M.; Omar, Shaheed V.; Koornhof, Hendrik; Dreyer, Andries W.; Musekiwa, Alfred; Moultrie, Harry; Hoosen, Anwar A.; Kaplan, Gilla; Fallows, Dorothy; Ismail, Nazir
    ENGLISH SUMMARY : Treatment of tuberculosis (TB) and HIV co-infections is often complicated by drug-to-drug interactions between anti-mycobacterial and anti-retroviral agents. Rifabutin (RFB) is an alternative to rifampin (RIF) for TB regimens and is recommended for HIV patients concurrently receiving protease inhibitors because of reduced induction of CYP3A4. This study sought to determine the proportion of RFB susceptible isolates among RIF-resistant strains in a high HIV prevalence setting in South Africa. In addition, the study explored the association between rpoB mutations and minimum inhibitory concentrations (MIC) of RIF and RFB. A total of 189 multidrug resistant (MDR) Mycobacterium tuberculosis isolates from the Centre for Tuberculosis repository were analyzed. The MICs were determined using a MYCOTB Sensititre plate method and the rpoB gene was sequenced. Of the 189 MDR isolates, 138 (73%) showed resistance to both RIF and RFB, while 51 (27%) isolates were resistant to RIF but retained susceptibility to RFB. The S531L was the most frequent rpoB point mutation in 105/189 (56%) isolates, followed by H526Y in 27/189 (14%) isolates. Resistance to both RIF and RFB was found predominantly in association with mutations S531L (91/105, 87%), H526Y (20/27, 74%), and H526D (15/19, 79%), while D516V (15/17, 88%), and L533P (3/4, 75%) were found in RIF-resistant, RFB-susceptible isolates. This study has shown that up to 27% of MDR-TB patients in South Africa may benefit from a treatment regimen that includes RFB.
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    Effect of standard tuberculosis treatment on plasma cytokine levels in patients with active pulmonary tuberculosis
    (Public Library of Science, 2012-05-14) Riou, Catherine; Peixoto, Blas Perez; Roberts, Lindi; Ronacher, Katharina; Walzl, Gerhard; Manca, Claudia; Rustomjee, Roxana; Mthiyane, Thuli; Fallows, Dorothy; Gray, Clive M.; Kaplan, Gilla
    Background: Sputum Mycobacterium tuberculosis (Mtb) culture is commonly used to assess response to antibiotic treatment in individuals with pulmonary tuberculosis (TB). Such techniques are constrained by the slow growth rate of Mtb, and more sensitive methods to monitor Mtb clearance are needed. The goal of this study was to evaluate changes in plasma cytokines in patients undergoing treatment for TB as a means of identifying candidate host markers associated with microbiologic response to therapy. Methods: Twenty-four plasma cytokines/chemokines were measured in 42 individuals diagnosed with active pulmonary TB, 52% were HIV co-infected. Individuals, undergoing a 26-week standard TB treatment, were followed longitudinally over 18 months and measurements were associated with HIV status and rates of sputum culture conversion. Results: Plasma concentrations of interferon-inducible protein-10 (IP-10) and vascular endothelial growth factor (VEGF) were significantly reduced upon TB treatment, regardless of HIV status. By the end of treatment, IP-10 concentrations were significantly lower in HIV negative individuals when compared to HIV-positive individuals (p = 0.02). Moreover, in HIV negative patients, plasma VEGF concentrations, measured as early as 2-weeks post TB treatment initiation, positively correlated with the time of sputum conversion (p = 0.0017). No significant changes were observed in other studied immune mediators. Conclusions: These data suggest that VEGF plasma concentration, measured during early TB treatment, could represent a surrogate marker to monitor sputum culture conversion in HIV uninfected individuals.
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    A metabolic biosignature of early response to anti-tuberculosis treatment
    (BioMed Central, 2014-01) Mahapatra, Sebabrata; Hess, Ann M.; Johnson, John L.; Eisenach, Kathleen D.; DeGroote, Mary A.; Gitta, Phineas; Joloba, Moses L.; Kaplan, Gilla; Walzl, Gerhard; Boom, W. H.; Belisle, John T.
    Background The successful treatment of tuberculosis (TB) requires long-term multidrug chemotherapy. Clinical trials to evaluate new drugs and regimens for TB treatment are protracted due to the slow clearance of Mycobacterium tuberculosis (Mtb) infection and the lack of early biomarkers to predict treatment outcome. Advancements in the field of metabolomics make it possible to identify metabolic profiles that correlate with disease states or successful chemotherapy. However, proof-of-concept of this approach has not been provided for a TB-early treatment response biosignature (TB-ETRB). Methods Urine samples collected at baseline and during treatment from 48 Ugandan and 39 South African HIV-seronegative adults with pulmonary TB were divided into discovery and qualification sets, normalized to creatinine concentration, and analyzed by liquid chromatography-mass spectrometry to identify small molecule molecular features (MFs) in individual patient samples. A biosignature that distinguished baseline and 1 month treatment samples was selected by pairwise t-test using data from two discovery sample sets. Hierarchical clustering and repeated measures analysis were applied to additional sample data to down select molecular features that behaved consistently between the two clinical sites and these were evaluated by logistic regression analysis. Results Analysis of discovery samples identified 45 MFs that significantly changed in abundance at one month of treatment. Down selection using an extended set of discovery samples and qualification samples confirmed 23 MFs that consistently changed in abundance between baseline and 1, 2 and 6 months of therapy, with 12 MFs achieving statistical significance (p < 0.05). Six MFs classified the baseline and 1 month samples with an error rate of 11.8%. Conclusions These results define a urine based TB-early treatment response biosignature (TB-ETRB) applicable to different parts of Africa, and provide proof-of-concept for further evaluation of this technology in monitoring clinical responses to TB therapy.
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    Translational research for tuberculosis elimination : priorities, challenges, and actions
    (Public Library of Science, 2016) Lienhardt, Christian; Lonnroth, Knut; Menzies, Dick; Balasegaram, Manica; Chakaya, Jeremiah; Cobelens, Frank; Cohn, Jennifer; Denkinger, Claudia M.; Evans, Thomas G.; Kallenius, Gunilla; Kaplan, Gilla; Kumar, Ajay M. V.; Matthiessen, Line; Mgone, Charles S.; Mizrahi, Valerie; Mukadi, Ya-diul; Nguyen, Viet Nhung; Nordstrom, Anders; Sizemore, Christine F.; Spigelman, Melvin; Squire, S. Bertel; Swaminathan, Soumya; Van Helden, Paul D.; Zumla, Alimuddin; Weyer, Karin; Weil, Diana; Raviglione, Mario
    Summary Points: • The WHO End TB Strategy, endorsed by the World Health Assembly in May 2014, has the ambitious goal of ending the global tuberculosis (TB) epidemic by 2035, with targets of a 95% decline in deaths due to TB (compared with 2015) and a 90% reduction in incidence of TB to ten cases/100,000 or less and no TB-affected household experiencing catastrophic costs due to TB. • Achieving this goal will only be possible through the development and rapid uptake of new tools, including rapid point-of-care diagnostics, safe and shorter treatment of latent TB infection and disease, and an efficacious TB vaccine, combined with efficient health systems and care provision, and actions on the social determinants of TB. • Research for TB elimination requires an intensification of efforts across a continuum from fundamental research to clinical, epidemiological, implementation, health system, and social science research. • Enhancing research along the full spectrum, from basic to implementation, and strengthening research capacity, particularly in low- and middle-income countries severely affected by the TB epidemics, is crucial for TB elimination. • The creation of a research-enabling environment that fosters and rewards high-quality research requires a broad-based, concerted effort by national governments and international donors to develop and promote TB research and research capacity at the country level and the effective engagement of all stakeholders.