Usability of rectal swabs for microbiome sampling in a cohort study of hematological and oncological patients

Objectives Large-scale clinical studies investigating associations between intestinal microbiota signatures and human diseases usually rely on stool samples. However, the timing of repeated stool sample collection cannot be predefined in longitudinal settings. Rectal swabs, being straightforward to obtain, have the potential to overcome this drawback. Therefore, we assessed the usability of rectal swabs for microbiome sampling in a cohort of hematological and oncological patients. Study design We used a pipeline for intestinal microbiota analysis from deep rectal swabs which was established and validated with test samples and negative controls. Consecutively, a cohort of patients from hematology and oncology wards was established and weekly deep rectal swabs taken during their admissions and re-admissions. Results Validation of our newly developed pipeline for intestinal microbiota analysis from rectal swabs revealed consistent and reproducible results. Over a period of nine months, 418 rectal swabs were collected longitudinally from 41 patients. Adherence to the intended sampling protocol was 97%. After DNA extraction, sequencing, read pre-processing and filtering of chimeric sequences, 405 of 418 samples (96.9%) were eligible for further analyses. Follow-up samples and those taken under current antibiotic exposure showed a significant decrease in alpha diversity as compared to baseline samples. Microbial domination occurred most frequently by Enterococcaceae (99 samples, 24.4%) on family level and Enterococcus (90 samples, 22.2%) on genus level. Furthermore, we noticed a high abundance of potential skin commensals in 99 samples (24.4%). Summary Deep rectal swabs were shown to be reliable for microbiome sampling and analysis, with practical advantages related to high sampling adherence, easy timing, transport and storage. The relatively high abundance of putative skin commensals in this patient cohort may be of potential interest and should be further investigated. Generally, previous findings on alpha diversity dynamics obtained from stool samples were confirmed

Combined analysis of gut microbiota, diet and PNPLA3 polymorphism in biopsy‐proven non‐alcoholic fatty liver disease

Background and aims: Non-alcoholic fatty liver disease (NAFLD) is a global health burden. Risk factors for disease severity include older age, increased body mass index (BMI), diabetes, genetic variants, dietary factors and gut microbiota alterations. However, the interdependence of these factors and their individual impact on disease severity remain unknown. Methods: In this cross-sectional study, we performed 16S gene sequencing using fecal samples, collected dietary intake, PNPLA3 gene variants and clinical and liver histology parameters in a well-described cohort of 180 NAFLD patients. Principal component analyses were used for dimensionality reduction of dietary and microbiota data. Simple and multiple stepwise ordinal regression analyses were performed. Results: Complete data were available for 57 NAFLD patients. In the simple regression analysis, features associated with the metabolic syndrome had the highest importance regarding liver disease severity. In the multiple regression analysis, BMI was the most important factor associated with the fibrosis stage (OR per kg/m2 : 1.23, 95% CI 1.10-1.37, P < .001). The PNPLA3 risk allele had the strongest association with the histological grade of steatosis (OR 5.32, 95% CI 1.56-18.11, P = .007), followed by specific dietary patterns. Low abundances of Faecalibacterium, Bacteroides and Prevotella and high abundances of Gemmiger were associated with the degree of inflammation, ballooning and stages of fibrosis, even after taking other cofactors into account. Conclusions: BMI had the strongest association with histological fibrosis, but PNPLA3 gene variants, gut bacterial features and dietary factors were all associated with different histology features, which underscore the multifactorial pathogenesis of NAFLD

High Intracellular Concentrations of Posaconazole Do Not Impact on Functional Capacities of Human Polymorphonuclear Neutrophils and Monocyte-Derived Macrophages In Vitro

Posaconazole is a commonly used antifungal for the prophylaxis and treatment of invasive fungal infections. We previously demonstrated that the intracellular concentration of posaconazole in peripheral blood mononuclear cells (PBMCs) and polymorphonuclear neutrophils (PMNs) was greatly increased compared to the plasma concentration. As these professional phagocytes are crucial to combat fungal infections, we set out to investigate if and how, beneficial or deleterious, this high loading of intracellular posaconazole impacts the functional capacities of these cells. Here, we show that high intracellular concentrations of posaconazole do not significantly impact PMN and monocyte-derived macrophage function in vitro. In particular, killing capacity and cytoskeletal features of PMN, such as migration, are not affected, indicating that these cells serve as vehicles for posaconazole to the site of infection. Moreover, since posaconazole as such slowed the germination of Aspergillus fumigatus conidia, infected neutrophils released less reactive oxygen species (ROS). Based on these findings, we propose that the delivery of posaconazole by neutrophils to the site of Aspergillus species infection warrants control of the pathogen and preservation of tissue integrity at the same time

Changes in the cervical microbiota of cervical cancer patients after primary radio-chemotherapy

Objective Several recent studies have identified a potential interaction between the vaginal microbiota and gynecological cancers, but little is known about the cervical microbiota and its changes during cancer treatment. Therefore, the aim of the study was to evaluate the quantitative and qualitative changes of cervical microbiota in patients undergoing concurrent chemotherapy and radiation treatment for locally advanced cervical cancer. Methods Cervical cytobrush samples of 15 cervical patients undergoing chemoradiation treatment were collected 1 day before starting external beam radiation therapy and on the day of the last fraction of brachytherapy. After DNA extraction, 16S rRNA amplicon sequencing of the V3-V4 region was performed on the MiSeq platform, followed by data processing and statistical analyses concerning the alpha and beta diversity of 16 samples (7 samples were excluded because of incomplete sample sets). Results The amount of amplicon yield after polymerase chain reaction analysis in post-radiation samples was significantly lower compared with the baseline samples (pre 31.49 +/- 24.07 ng/mu l; post 1.33 +/- 1.94 ng/mu l; p=0.007). A comparison of pre-treatment and post-treatment samples did not show significant differences regarding beta diversity (weighted UniFrac). There was no significant difference in alpha diversity, which is used to characterize species diversity within a particular community and takes into account both number and abundance (Shannon Diversity Index pre-treatment samples: 2.167 +/- 0.7504 (95% CI 1.54 to 2.79); post-treatment samples: 1.97 +/- 0.43 (95% CI 1.61 to 2.33); p=0.38). Interindividual differences in patients could partly explain some variation of the samples (permutational multivariate analysis of variance). Conclusion There was a strong reduction in cervical bacterial loads after chemoradiation. Neither alpha nor beta diversity varied significantly when baseline samples were compared with post-treatment samples

Low penetration of caspofungin into cerebrospinal fluid following intravenous administration of standard doses

The kinetics of caspofungin (CAS) in cerebrospinal fluid (CSF) following intravenous (i.v.) administration has been studied exclusively in animal models. Human data are missing so far. In this study, 13 CSF samples were obtained at different time points following i.v. infusion of CAS in ten paediatric haemato-/oncological patients (age range 1.0-14.2 years, median 8.6 years) without signs of central nervous system (CNS) infection (n = 10 samples) or with infectious meningitis (n = 3 samples). Serum samples were obtained concurrently. Liquid chromatography-tandem mass spectrometry was used for CAS quantification. Whilst CAS serum levels were in the expected range, varying between 0.6 and 20.3 mu g/mL (median 7.0 mu g/mL), 11 of 13 CSF levels were below the limit of detection of 0.084 mu g/mL at 3.0-48.0 h (median 23.3 h) following i.v. infusion. Only two (of three) levels in patients with bacterial meningitis were above the limit of detection (0.3 mu g/mL and 0.09 mu g/mL, respectively). These results indicate the low capacity of CAS to penetrate into the CNS even in inflamed meninges. Monotherapy with standard doses of CAS appears not to be suitable for treatment of fungal CNS infections. (C) 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved

Fecal microbiota transplantation in a kidney transplant recipient with recurrent urinary tract infection

Purpose We report on a kidney transplant recipient treated with fecal microbiota transplantation (FMT) for recurrent urinary tract infections. Methods FMT was administered via frozen capsulized microbiota. Before and after FMT, urinary, fecal and vaginal microbiota compositions were analyzed. Results The patient remained without symptoms after FMT. Conclusions Underlying mechanisms of action need to be addressed in depth by future research

Intracellular Concentrations of Posaconazole in Different Compartments of Peripheral Blood▿

Therapeutic drug monitoring (TDM) of antifungal plasma concentrations is increasingly recommended. However, data on antifungal concentrations in the other compartments of the peripheral blood are limited. Hence, we collected 23 blood samples from 14 patients receiving posaconazole for prophylaxis of fungal infections. These samples were separated by double-discontinuous Ficoll-Hypaque density gradient centrifugation. The intracellular posaconazole concentrations of the obtained cells, i.e., the peripheral blood mononuclear cells (PBMCs), polymorphonuclear leukocytes (PMNs), and red blood cells (RBCs), were determined by liquid chromatography-tandem mass spectrometry. The intracellular concentrations of the PBMCs and PMNs were significantly higher than those of surrounding media (P < 0.001). The ratios between the intracellular and extracellular concentrations (C/E) were 22.5 ± 21.2, 7.66 ± 6.50, and 0.09 ± 0.05 for the PBMCs, PMNs, and RBCs, respectively. Posaconazole reaches high concentrations within human PBMCs and PMNs and is, to a lesser extent, present in RBCs. The high intracellular concentrations might contribute to posaconazole efficacy and distribution

Pharmacokinetic Modeling of Voriconazole To Develop an Alternative Dosing Regimen in Children

The pharmacokinetic variability of voriconazole (VCZ) in immunocompromised children is high, and adequate exposure, particularly in the first days of therapy, is uncertain. A population pharmacokinetic model was developed to explore VCZ exposure in plasma after alternative dosing regimens. Concentration data were obtained from a pediatric phase II study. Nonlinear mixed effects modeling was used to develop the model. Monte Carlo simulations were performed to test an array of three-times-daily (TID) intravenous dosing regimens in children 2 to 12 years of age. A two-compartment model with first-order absorption, nonlinear Michaelis-Menten elimination, and allometric scaling best described the data (maximal kinetic velocity for nonlinear Michaelis-Menten clearance [V-max] = 51.5 mg/h/70 kg, central volume of distribution [V-1] = 228 liters/70 kg, intercompartmental clearance [Q] = 21.9 liters/h/70 kg, peripheral volume of distribution [V-2] = 1,430 liters/70 kg, bioavailability [F] = 59.4%, K-m = fixed value of 1.15 mg/liter, absorption rate constant = fixed value of 1.19 h(-1)). Interindividual variabilities for V-max, V-1, Q, and F were 63.6%, 45.4%, 67%, and 1.34% on a logit scale, respectively, and residual variability was 37.8% (proportional error) and 0.0049 mg/liter (additive error). Monte Carlo simulations of a regimen of 9 mg/kg of body weight TID simulated for 24, 48, and 72 h followed by 8 mg/kg two times daily (BID) resulted in improved early target attainment relative to that with the currently recommended BID dosing regimen but no increased rate of accumulation thereafter. Pharmacokinetic modeling suggests that intravenous TID dosing at 9 mg/kg per dose for up to 3 days may result in a substantially higher percentage of children 2 to 12 years of age with adequate exposure to VCZ early during treatment. Before implementation of this regimen in patients, however, validation of exposure, safety, and tolerability in a carefully designed clinical trial would be needed