Publications by authors named "Jotam G Pasipanodya"

Background/objectives: In sub-Saharan Africa, there is paucity of data regarding non-tuberculous mycobacterial (NTM) infections, leading to underappreciation of disease burden. Consequently, fewer resources are allocated, leading to potential adverse outcomes. This study examines long-term mortality and risk factors of South African patients with positive NTM samples.

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Introduction: Tuberculosis (TB) is the leading infectious cause of death globally. Despite WHO recommendations for Tuberculosis Preventive Therapy (TPT), challenges persist, including incompletion of treatment and adverse drug reactions (ADRs). There is limited data on the 3-month isoniazid and rifapentine (3HP) pharmacokinetics, pharmacogenomics and their relation with ADRs.

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Background: The disproportionate burden of viral hepatitis, particularly hepatitis B virus (HBV) is experienced by people living in low-resourced sub-Saharan Africa, where the estimated prevalence is 3-7 times the global average. Therefore to inform policy, we describe the seroprevalence and trends of hepatitis C (HCV) and HBV biomarkers: anti-HCV antibody and hepatitis B surface antigen (HBsAg), respectively, in Zimbabwe.

Methods: We analysed data from 181,248 consecutive blood-donors, examined between January 2015 through December 2018.

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Antimicrobial susceptibility testing, based on clinical breakpoints that incorporate pharmacokinetics/pharmacodynamics (PK/PD) and clinical outcomes, is becoming a new standard in guiding individual patient therapy as well as for drug resistance surveillance. However, for most antituberculosis drugs, breakpoints are instead defined by the epidemiological cutoff values of the MIC of phenotypically wild-type strains irrespective of PK/PD or dose. In this study, we determined the PK/PD breakpoint for delamanid by estimating the probability of target attainment for the approved dose administered at 100 mg twice daily using Monte Carlo experiments.

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Background: The hollow-fibre system model of tuberculosis (HFS-TB) has been endorsed by regulators; however, application of HFS-TB requires a thorough understanding of intra- and inter-team variability, statistical power and quality controls.

Methods: Three teams evaluated regimens matching those in the Rapid Evaluation of Moxifloxacin in Tuberculosis (REMoxTB) study, plus two high-dose rifampicin/pyrazinamide/moxifloxacin regimens, administered daily for up to 28 or 56 days against Mycobacterium tuberculosis (Mtb) under log-phase growth, intracellular growth or semidormant growth under acidic conditions. Target inoculum and pharmacokinetic parameters were pre-specified, and the accuracy and bias at achieving these calculated using percent coefficient of variation (%CV) at each sampling point and two-way analysis of variance (ANOVA).

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There is need for shorter duration regimens for the treatment of , that can treat patients regardless of multidrug resistance status (pan-tuberculosis). We combined minocycline with tedizolid, moxifloxacin, and rifampin, in the hollow fiber system model of and mimicked each drugs' intrapulmonary pharmacokinetics for 28 days. Minocycline-tedizolid was administered either as a once-a-week or a daily regimen.

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Background: Rifampin-resistant and/or multidrug-resistant tuberculosis (RR/MDR-TB) treatment requires multiple drugs, and outcomes remain suboptimal. Some drugs are associated with improved outcome. It is unknown whether particular pharmacokinetic-pharmacodynamic relationships predict outcome.

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Objectives: The standard of care (SOC) for the treatment of pulmonary Mycobacterium avium complex (MAC) disease (clarithromycin, rifabutin, and ethambutol) achieves sustained sputum conversion rates of only 54%. Thus, new treatments should be prioritized.

Methods: We identified the omadacycline MIC against one laboratory MAC strain and calculated drug half life in solution, which we compared with measured MAC doubling times.

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Objectives: The aim of this study was to determine and compare the efficacy of drugs to treat Mycobacterium kansasii (Mkn) pulmonary disease by performing minimum inhibitory concentration (MIC) determination and time-kill studies.

Methods: We determined the MICs to 13 drugs against the Mkn standard laboratory strain ATCC 12478 and 20 clinical isolates and performed time-kill studies with 18 drugs from different classes using the standard laboratory strain of Mkn. The β-lactam antibiotics were tested with or without the combination of the β-lactamase inhibitor avibactam.

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Among those who study granulomatous diseases, sarcoidosis is of tremendous interest, not only because its cause is unknown, but also because it is still as much an enigma today as it was 150 years ago when Jonathan Hutchinson first described the cutaneous form of the disease as "livid papillary psoriasis". This piece editorializes a comparative effectiveness study of methotrexate versus methylprednisolone in treatment naïve pulmonary sarcoidosis patients for CT-guided clinical responses and drug-related adverse events.

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Article Synopsis
  • There is an urgent need for predictive biomarkers to assess long-term TB treatment outcomes, as current methods are expensive and time-consuming.
  • Using mathematical modeling and machine learning, researchers identified a promising biomarker based on the bacterial kill rates during the first 8 weeks of treatment.
  • This new model showed a high sensitivity of 92% and specificity of 89% in predicting relapse-free cure, outperforming existing methods significantly, which have sensitivities below 34%.
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Article Synopsis
  • The study examines the effectiveness of standard therapy and alternative regimens for treating pulmonary disease, highlighting the need for shorter treatment durations.
  • Researchers analyzed data from 32 patients to calculate bacterial kill slopes and time-to-extinction using a hollow fiber system model, revealing significant differences in effectiveness between therapies.
  • The findings suggest that certain combinations, like rifampin-moxifloxacin-tedizolid, could serve as effective short-course treatment options with high rates of patient cure at 6 and 12 months.
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Background: There is a general dearth of information on extrapulmonary tuberculosis (EPTB). Here, we investigated Mycobacterium tuberculosis (Mtb) drug resistance and transmission patterns in EPTB patients treated in the Tshwane metropolitan area, in South Africa.

Methods: Consecutive Mtb culture-positive non-pulmonary samples from unique EPTB patients underwent mycobacterial genotyping and were assigned to phylogenetic lineages and transmission clusters based on spoligotypes.

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Background: Reduced ethambutol serum concentrations are commonly observed among TB patients co-infected with HIV and may lead to treatment failure.

Objectives: To perform a population pharmacokinetic study of ethambutol in HIV/TB patients, and to evaluate an intensified ethambutol weight-based dosing strategy to support pharmacokinetic target attainment.

Methods: We conducted a prospective study of ethambutol pharmacokinetics among HIV/TB patients administered first-line TB treatment in Botswana, with study visits before and after initiation of ART.

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There is poor understanding about protective immunity and the pathogenesis of cavitation in patients with tuberculosis. To map pathophysiological pathways at anatomically distinct positions within the human tuberculosis cavity. Biopsies were obtained from eight predetermined locations within lung cavities of patients with multidrug-resistant tuberculosis undergoing therapeutic surgical resection ( = 14) and healthy lung tissue from control subjects without tuberculosis ( = 10).

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Drug-resistant tuberculosis represents a global emergency, requiring new drugs. We found that minocycline was highly potent in laboratory strains of Mycobacterium tuberculosis and that 30 drug-susceptible and multidrug/extensively drug-resistant clinical strains were susceptible to clinically achievable concentrations. In the hollow fiber system model, lung concentration-time profiles of 7 mg/kg/day human-equivalent minocycline dose achieved bacterial kill rates equivalent to those of first-line antituberculosis agents.

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Background: A major challenge in medicine is translation of preclinical model findings to humans, especially therapy duration. One major example is recent shorter-duration therapy regimen failures in tuberculosis.

Methods: We used set theory mapping to develop a computational/modeling framework to map the time it takes to extinguish the Mycobacterium tuberculosis population on chemotherapy from multiple hollow fiber system model of tuberculosis (HFS-TB) experiments to that observed in patients.

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Background: Levofloxacin is used for the treatment of multidrug-resistant tuberculosis; however the optimal dose is unknown.

Methods: We used the hollow fiber system model of tuberculosis (HFS-TB) to identify 0-24 hour area under the concentration-time curve (AUC0-24) to minimum inhibitory concentration (MIC) ratios associated with maximal microbial kill and suppression of acquired drug resistance (ADR) of Mycobacterium tuberculosis (Mtb). Levofloxacin-resistant isolates underwent whole-genome sequencing.

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Background: Gatifloxacin is used for the treatment of multidrug-resistant tuberculosis (MDR-TB). The optimal dose is unknown.

Methods: We performed a 28-day gatifloxacin hollow-fiber system model of tuberculosis (HFS-TB) study in order to identify the target exposures associated with optimal kill rates and resistance suppression.

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Background: In the experimental arm of the OFLOTUB trial, gatifloxacin replaced ethambutol in the standard 4-month regimen for drug-susceptible pulmonary tuberculosis. The study included a nested pharmacokinetic (PK) study. We sought to determine if PK variability played a role in patient outcomes.

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Background: Ethionamide is used to treat multidrug-resistant tuberculosis (MDR-TB). The antimicrobial pharmacokinetics/pharmacodynamics, the contribution of ethionamide to the multidrug regimen, and events that lead to acquired drug resistance (ADR) are unclear.

Methods: We performed a multidose hollow fiber system model of tuberculosis (HFS-TB) study to identify the 0-24 hour area under the concentration-time curve (AUC0-24) to minimum inhibitory concentration (MIC) ratios that achieved maximal kill and ADR suppression, defined as target exposures.

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Article Synopsis
  • Acquired resistance poses a significant challenge in treating multidrug-resistant tuberculosis (TB), but its origins and development are not well understood.
  • Researchers aimed to explore the link between antibiotic concentrations and TB drug susceptibility by analyzing samples from patients undergoing surgery for severe TB.
  • Findings revealed that drug concentrations varied significantly within the TB cavities, affecting the minimum inhibitory concentrations (MICs) of antibiotics, indicating a complex interplay between drug levels and resistance development that informs future treatment strategies.
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