Enteropathogen spectrum and effect on antimycobacterial pharmacokinetics among children with tuberculosis in rural Tanzania: a prospective cohort study.

BACKGROUND: Enteropathy is prevalent in tuberculosis-endemic areas, and it has been shown to impair intestinal absorptive function; therefore, enteropathogen burden might negatively affect antimycobacterial pharmacokinetics, particularly among malnourished children. We sought to quantify enteropathogen burden among children initiating tuberculosis treatment in rural Tanzania and determine the effect of enteropathogen burden on serum antimycobacterial pharmacokinetics. METHODS: We performed a prospective cohort study at one site in rural Tanzania as an exploratory substudy of a large multicountry cohort study. We included children younger than 15 years of age with confirmed or probable tuberculosis undergoing treatment with first-line tuberculosis therapy; children were excluded from the study if they were unable to undergo sample collection. Participants were consecutively recruited from the inpatient paediatric wards or the outpatient tuberculosis clinic at Haydom Lutheran Hospital, Tanzania. The main outcome was to quantify symptomatic enteropathogen burden and the effect on serum antimycobacterial pharmacokinetics. We quantified enteropathogen burden (defined as the sum of distinct enteropathogens detected in stool) using a multipathogen PCR capable of simultaneous detection of 37 bacterial, viral, and parasitic species or species groups from stool collected within 72 h of treatment initiation. Comprehensive clinical assessment, including presence of gastrointestinal symptoms, was performed at baseline, and serum was collected approximately 2 weeks after treatment initiation at steady state and throughout the dosing interval with concentrations of isoniazid, rifampicin, pyrazinamide, and ethambutol measured by liquid chromatography with a tandem mass spectrometry assay to quantify peak (Cmax) and total area under the concentration curve (AUC0-24), as determined by non-compartmental analysis. Enteropathogen burden was compared with pharmacokinetic measurements using bivariable and multivariable linear regression. FINDINGS: 58 children were assessed for eligibilty and enrolled between June 25, 2016, and Feb 6, 2018; 44 had complete stool testing and serum pharmacokinetic data, and they were included in the analyses. 20 (45%) were female, and 24 (55%) were male. 37 (84%) had moderate or severe malnutrition. A mean of 2·1 (SD 1·3) enteropathogens were detected per participant. Target peak concentrations of rifampicin were reached in eight (18%) of 44 participants, isoniazid in 24 (54%) of 44 participants, pyrazinamide in 28 (74%) of 38 participants, and ethambutol in six (15%) of 39 participants. Compared with controlled comparisons, each summative additional bacterial enteropathogen detected was associated with a 40% lower rifampicin Cmax (95% CI -62 to -5) and a 36% lower ethambutol Cmax (-52 to -14), while viral pathogens were associated with a 51% lower isoniazid Cmax (-75 to -7). The combination of gastrointestinal symptoms and detection of an additional enteropathogen was associated with a 27% reduction in rifampicin AUC0-24 (95% CI -47 to -1). INTERPRETATION: Tanzanian children undergoing tuberculosis treatment rarely attained pharmacokinetic targets; enteropathogen carriage was common and enteropathogen burden was associated with significant reductions in the concentrations of some antimycobacterial drugs. Further research should explore mechanistic relationships of individual pathogens and antimycobacterial pharmacokinetics in larger cohorts, or determine if screening for and treating enteropathogens at tuberculosis treatment initiation improves pharmacokinetic target attainment. FUNDING: National Institute of Allergy and Infectious Diseases, National Institutes of Health. TRANSLATION: For the Swahili translation of the abstract see Supplementary Materials section.

Use of cauliflower mosaic virus DNA markers to assess the potential for pathogen transmission from physicians' white coats.

In an observational study, the sleeves and pockets of physicians' white coats often directly or indirectly contacted patients and environmental surfaces. DNA markers on the sleeves or pockets were frequently transferred to surfaces and patients. These findings suggest that contaminated white coats have the potential to contribute to pathogen transmission.

Food for thought: addressing undernutrition to end tuberculosis.

Tuberculosis is the leading cause of deaths from an infectious disease worldwide. WHO's End TB Strategy is falling short of several 2020 targets. Undernutrition is the leading population-level risk factor for tuberculosis. Studies have consistently found that undernutrition is associated with increased tuberculosis incidence, increased severity, worse treatment outcomes, and increased mortality. Modelling studies support implementing nutritional interventions for people living with tuberculosis and those at risk of tuberculosis disease to ensure the success of the End TB Strategy. In this Personal View, we highlight nutrition-related immunocompromisation, implications of undernutrition for tuberculosis treatment and prevention, the role of nutritional supplementation, pharmacokinetics and pharmacodynamics of antimycobacterial medications in undernourished people with tuberculosis, and the role of social protection interventions in addressing undernutrition as a tuberculosis risk factor. To catalyse action on this insufficiently addressed accelerant of the global tuberculosis epidemic, research should be prioritised to understand the immunological pathways that are impaired by nutrient deficiencies, develop tools to diagnose clinical and subclinical tuberculosis in people who are undernourished, and understand how nutritional status affects the efficacy of tuberculosis vaccine and therapy. Through primary research, modelling, and implementation research, policy change should also be accelerated, particularly in countries with a high burden of tuberculosis.

Determination of Rifampin Concentrations by Urine Colorimetry and Mobile Phone Readout for Personalized Dosing in Tuberculosis Treatment.

BACKGROUND: Individual pharmacokinetic variability is a driver of poor tuberculosis (TB) treatment outcomes. We developed a method for measurement of rifampin concentrations by urine colorimetry and a mobile phone photographic application to predict clinically important serum rifampin pharmacokinetic measurements in children treated for TB. METHODS: Among spiked urine samples, colorimetric assay performance was tested with conventional spectrophotometric and the mobile phone/light box methods under various environmental and biologic conditions. Urine rifampin absorbance (Abs) was then determined from timed specimens from children treated for TB in Tanzania, and compared to serum pharmacokinetic measurements collected throughout the dosing interval. RESULTS: Both the mobile phone/light box and spectrophotometry demonstrated excellent correlation across a wide range of urine rifampin concentrations (7.8-1000 mg/L) in intra- and interday trials, 24-hour exposure to ambient light or darkness, and varying urinalysis profiles (all r ≥ 0.98). In 12 Tanzanian children, the urine mobile phone/light box measurement and serum peak concentration (Cmax) were significantly correlated (P = .004). Using a Cmax target of 8 mg/L, the area under the receiver operating characteristic curve was 80.1% (range, 47.2%-100%). A urine mobile phone/light box threshold of 50 Abs correctly classified all patients (n = 6) with serum measurements below target. CONCLUSIONS: The urine colorimetry with mobile phone/light box assay accurately measured rifampin absorbance in varying environmental and biological conditions that may be observed clinically. Among children treated for TB, the assay was sensitive for detection of low rifampin serum concentrations. Future work will identify the optimal timing for urine collection, and operationalize use in TB-endemic settings.

Highly conserved influenza T cell epitopes induce broadly protective immunity.

Influenza world-wide causes significant morbidity and mortality annually, and more severe pandemics when novel strains evolve to which humans are immunologically naïve. Because of the high viral mutation rate, new vaccines must be generated based on the prevalence of circulating strains every year. New approaches to induce more broadly protective immunity are urgently needed. Previous research has demonstrated that influenza-specific T cells can provide broadly heterotypic protective immunity in both mice and humans, supporting the rationale for developing a T cell-targeted universal influenza vaccine. We used state-of-the art immunoinformatic tools to identify putative pan-HLA-DR and HLA-A2 supertype-restricted T cell epitopes highly conserved among > 50 widely diverse influenza A strains (representing hemagglutinin types 1, 2, 3, 5, 7 and 9). We found influenza peptides that are highly conserved across influenza subtypes that were also predicted to be class I epitopes restricted by HLA-A2. These peptides were found to be immunoreactive in HLA-A2 positive but not HLA-A2 negative individuals. Class II-restricted T cell epitopes that were highly conserved across influenza subtypes were identified. Human CD4+ T cells were reactive with these conserved CD4 epitopes, and epitope expanded T cells were responsive to both H1N1 and H3N2 viruses. Dendritic cell vaccines pulsed with conserved epitopes and DNA vaccines encoding these epitopes were developed and tested in HLA transgenic mice. These vaccines were highly immunogenic, and more importantly, vaccine-induced immunity was protective against both H1N1 and H3N2 influenza challenges. These results demonstrate proof-of-principle that conserved T cell epitopes expressed by widely diverse influenza strains can induce broadly protective, heterotypic influenza immunity, providing strong support for further development of universally relevant multi-epitope T cell-targeting influenza vaccines.

Ibrutinib Therapy and Mycobacterium chelonae Skin and Soft Tissue Infection.

Ibrutinib is an irreversible inhibitor of Bruton's tyrosine kinase approved for the treatment of B-cell malignancies. There is growing concern about the risk of opportunistic infections following ibrutinib therapy. Herein, we describe the first case of Mycobacterium chelonae skin and soft tissue infection in a patient receiving ibrutinib and recount the challenges in treating this infection.

An immunoinformatic approach for identification of Trypanosoma cruzi HLA-A2-restricted CD8(+) T cell epitopes.

Chagas disease is a major neglected tropical disease caused by persistent chronic infection with the protozoan parasite Trypanosoma cruzi. An estimated 8 million people are infected with T. cruzi, however only 2 drugs are approved for treatment and no vaccines are available. Thus there is an urgent need to develop vaccines and new drugs to prevent and treat Chagas disease. In this work, we identify T cell targets relevant for human infection with T. cruzi. The trans-sialidase (TS) gene family is a large family of homologous genes within the T. cruzi genome encoding over 1,400 members. There are 12 highly conserved TS gene family members which encode enzymatically active TS (functional TS; F-TS), while the remaining TS family genes are less conserved, enzymatically inactive and have been hypothesized to be involved in immune evasion (non-functional TS; NF-TS). We utilized immunoinformatic tools to identify HLA-A2-restricted CD8(+) T cell epitopes conserved within F-TS family members and NF-TS gene family members. We also utilized a whole-genome approach to identify T cell epitopes present within genes which have previously been shown to be expressed in life stages relevant for human infection (Non-TS genes). Thirty immunogenic HLA-A2-restricted CD8(+) T cell epitopes were identified using IFN-γ ELISPOT assays after vaccination of humanized HLA-A2 transgenic mice with mature dendritic cells pulsed with F-TS, NF-TS, and Non-TS peptide pools. The immunogenic HLA-A2-restricted T cell epitopes identified in this work may serve as potential components of an epitope-based T cell targeted vaccine for Chagas disease.