The European Paediatric Mycology Network (EPMyN) was launched in 2014 to create a European platform for research and education in the field of paediatric mycology. The EPMyN aims to address the lack of paediatric specific evidence and knowledge needed to (1) improve the management and outcome of invasive fungal infections in children and neonates and to (2) enhance and develop paediatric antifungal stewardship programmes.

Ligase IV syndrome is a rare differential diagnosis for Nijmegen breakage syndrome owing to a shared predisposition to lympho-reticular malignancies, significant microcephaly, and radiation hypersensitivity. Only 16 cases with mutations in LIG4 have been described to date with phenotypes varying from malignancy in developmentally normal individuals, to severe combined immunodeficiency and early mortality. Here, we report the identification of biallelic truncating LIG4 mutations in 11 patients with microcephalic primordial dwarfism presenting with restricted prenatal growth and extreme postnatal global growth failure (average OFC -10.1 s.d., height -5.1 s.d.). Subsequently, most patients developed thrombocytopenia and leucopenia later in childhood and many were found to have previously unrecognized immunodeficiency following molecular diagnosis. None have yet developed malignancy, though all patients tested had cellular radiosensitivity. A genotype-phenotype correlation was also noted with position of truncating mutations corresponding to disease severity. This work extends the phenotypic spectrum associated with LIG4 mutations, establishing that extreme growth retardation with microcephaly is a common presentation of bilallelic truncating mutations. Such growth failure is therefore sufficient to consider a diagnosis of LIG4 deficiency and early recognition of such cases is important as bone marrow failure, immunodeficiency, and sometimes malignancy are long term sequelae of this disorder.

Aspergillus fumigatus infects up to 50% of cystic fibrosis (CF) patients and may play a role in progressive lung disease. As cystic fibrosis transmembrane conductance regulator is expressed in cells of the innate immune system, we hypothesised that impaired antifungal immune responses play a role in CF-related Aspergillus lung disease. Peripheral blood mononuclear cells, polymorphonuclear cells (PMN) and monocytes were isolated from blood samples taken from CF patients and healthy volunteers. Live-cell imaging and colorimetric assays were used to assess antifungal activity in vitro. Production of reactive oxygen species (ROS) was measured using luminol-induced chemiluminescence and was related to clinical metrics as collected by case report forms. CF phagocytes are as effective as those from healthy controls with regards to phagocytosis, killing and restricting germination of A. fumigatus conidia. ROS production by CF phagocytes was up to four-fold greater than healthy controls (p<0.05). This effect could not be replicated in healthy phagocytes by priming with lipopolysaccharide or serum from CF donors. Increased production of ROS against A. fumigatus by CF PMN was associated with an increased number of clinical exacerbations in the previous year (p=0.007) and reduced lung function (by forced expiratory volume in 1 s) (p=0.014). CF phagocytes mount an intrinsic exaggerated release of ROS upon A. fumigatus stimulation which is associated with clinical disease severity.

Evidence for drug use in newborns is sparse, which may cause large differences in drug prescriptions. We aimed to investigate the differences between neonatal intensive care units (NICUs) in the Netherlands in currently prescribed drugs.

In order to survive, Aspergillus fumigatus must adapt to specific niche environments. Adaptation to the human host includes modifications facilitating persistent colonisation and the development of azole resistance. The aim of this study is to advance understanding of the genetic and physiological adaptation of A. fumigatus in patients during infection and treatment. Thirteen A. fumigatus strains were isolated from a single chronic granulomatous disease patient suffering from persistent and recurrent invasive aspergillosis over a period of 2 years. All strains had identical microsatellite genotypes and were considered isogenic. Whole genome comparisons identified 248 non-synonymous single nucleotide polymorphisms. These non-synonymous mutations have potential to play a role in in-host adaptation. The first 2 strains isolated were azole susceptible, whereas later isolates were itraconazole, voriconazole and/or posaconazole resistant. Growth assays in the presence and absence of various antifungal stressors highlighted minor changes in growth rate and stress resistance, with exception of one isolate showing a significant growth defect. Poor conidiation was observed in later isolates. In certain drug resistant isolates conidiation was restored in the presence of itraconazole. Differences in virulence were observed as demonstrated in a Galleria mellonella infection model. We conclude that the microevolution of A. fumigatus in this patient has driven the emergence of both Cyp51A-independent and Cyp51A-dependent, azole resistance mechanisms, and additional phenotypes that are likely to have promoted fungal persistence.

The human host comprises a range of specific niche environments. In order to successfully persist, pathogens such as Aspergillus fumigatus must adapt to these environments. One key example of in-host adaptation is the development of resistance to azole antifungals. Azole resistance in A. fumigatus is increasingly reported worldwide and the most commonly reported mechanisms are cyp51A mediated. Using a unique series of A. fumigatus isolates, obtained from a patient suffering from persistent and recurrent invasive aspergillosis over 2 years, this study aimed to gain insight into the genetic basis of in-host adaptation. Single nucleotide polymorphisms (SNPs) unique to a single isolate in this series, which had developed multi-azole resistance in-host, were identified. Two nonsense SNPs were recreated using CRISPR-Cas9; these were 213* in svf1 and 167* in uncharacterised gene AFUA_7G01960. Phenotypic analyses including antifungal susceptibility testing, mycelial growth rate assessment, lipidomics analysis and statin susceptibility testing were performed to associate genotypes to phenotypes. This revealed a role for svf1 in A. fumigatus oxidative stress sensitivity. In contrast, recapitulation of 167* in AFUA_7G01960 resulted in increased itraconazole resistance. Comprehensive lipidomics analysis revealed decreased ergosterol levels in strains containing this SNP, providing insight to the observed itraconazole resistance. Decreases in ergosterol levels were reflected in increased resistance to lovastatin and nystatin. Importantly, this study has identified a SNP in an uncharacterised gene playing a role in azole resistance via a non-cyp51A mediated resistance mechanism. This mechanism is of clinical importance, as this SNP was identified in a clinical isolate, which acquired azole resistance in-host.

When protease inhibitor (PI)-based second-line ART fails, guidelines recommend drug resistance testing and individualized third-line treatment. However, PI-resistant viral strains are rare and drug resistance testing is costly. We investigated whether less costly PI-exposure testing can be used to select those patients who would benefit most from drug resistance testing.

Antiretroviral therapy during pregnancy reduces the risk of vertical HIV-1 transmission. However, drug dosing is challenging as pharmacokinetics (PK) may be altered during pregnancy. We combined a pregnancy physiologically-based pharmacokinetic (PBPK) modeling approach with data on placental drug transfer to simulate maternal and fetal exposure to dolutegravir (DTG). First, a PBPK model for DTG exposure in healthy volunteers was established based on physiological and DTG PK data. Next, the model was extended with a fetoplacental unit using transplacental kinetics obtained by performing ex vivo dual-side human cotyledon perfusion experiments. Simulations of fetal exposure after maternal dosing in the third trimester were in accordance with clinically observed DTG cord blood data. Furthermore, the predicted fetal trough plasma concentration (Ctrough ) following 50 mg q.d. dosing remained above the concentration that results in 90% of viral inhibition. Our integrated approach enables simulation of maternal and fetal DTG exposure, illustrating this to be a promising way to assess DTG PK during pregnancy.

Pemetrexed is used for the treatment for non-small cell lung cancer and mesothelioma. Patients with renal impairment are withheld treatment with this drug as it is unknown what dose is well tolerated in this population.

The need for pediatric antifungal stewardship programs has been driven by an increasing consumption of antifungals for prophylactic and empirical use. Drivers and rational of antifungal prescribing need to be identified to optimize prescription behaviors.

Neutropenia is a dose-related treatment-limiting and costly adverse event of pemetrexed. We postulate that individualized dosing reduces the incidence of neutropenia. The aims of this study were (i) to investigate the costs of pemetrexed-related neutropenia and (ii) to determine the pharmacoeconomic benefits of individualized dosing of pemetrexed in terms of budget impact, yearly cost savings, and reduction in severe neutropenia. Retrospective data on the treatment of grade 3 or higher neutropenia during pemetrexed-based chemotherapy were collected from three Dutch hospitals to determine the mean healthcare consumption during a neutropenic episode. Subsequently, Monte Carlo simulations were performed using a validated pharmacokinetic/pharmacodynamic model to predict the neutropenia incidence during four cycles for standard dosing of pemetrexed and individualized dosing. The mean costs per neutropenia and the expected neutropenia incidence were combined to calculate the budget impact and cost savings. We found that the average costs per pemetrexed-associated neutropenic episode to be €1,490 (US $1,674). The neutropenia incidence for the standard and individualized pemetrexed dosing strategies were 12.7% and 9.9%, respectively. This resulted in total expected neutropenia-related costs of ~ €3.0 million (US $3.372 million) and €2.4 million (US $2.697 million), respectively. Taking the number of patients eligible for pemetrexed treatment into account, individualized dosing could result in saving €686,000 (US $770,995) on a yearly basis in the Netherlands alone. Individualized dosing of pemetrexed can decrease the incidence of neutropenia and thus result in a significant decrease in neutropenia-related costs and decreased risk of hospitalization or even death while maintaining therapeutic exposure.

Plenary Sessions: [...].

We report a case of incomplete HIV-1 suppression on a dolutegravir, lamivudine, and abacavir single-tablet regimen with the emergence of the H51Y and G118R integrase resistance mutations.

Indoleamine 2,3-dioxygenases (IDOs) degrade l-tryptophan to kynurenines and drive the de novo synthesis of nicotinamide adenine dinucleotide. Unsurprisingly, various invertebrates, vertebrates, and even fungi produce IDO. In mammals, IDO1 also serves as a homeostatic regulator, modulating immune response to infection via local tryptophan deprivation, active catabolite production, and non-enzymatic cell signaling. Whether fungal Idos have pleiotropic functions that impact on host-fungal physiology is unclear. Here, we show that Aspergillus fumigatus possesses three ido genes that are expressed under conditions of hypoxia or tryptophan abundance. Loss of these genes results in increased fungal pathogenicity and inflammation in a mouse model of aspergillosis, driven by an alternative tryptophan degradation pathway to indole derivatives and the host aryl hydrocarbon receptor. Fungal tryptophan metabolic pathways thus cooperate with the host xenobiotic response to shape host-microbe interactions in local tissue microenvironments.

Once-daily two 600 mg tablets (1200 mg q.d.) raltegravir offers an easier treatment option compared to the twice-daily regimen of one 400 mg tablet. No pharmacokinetic, efficacy, or safety data of the 1200 mg q.d. regimen have been reported in pregnant women to date as it is challenging to collect these clinical data. This study aimed to develop a population pharmacokinetic (PopPK) model to predict the pharmacokinetic profile of raltegravir 1200 mg q.d. in pregnant women and to discuss the expected pharmacodynamic properties of raltegravir 1200 mg q.d. during pregnancy based on previously reported concentration-effect relationships. Data from 11 pharmacokinetic studies were pooled (n = 221). A two-compartment model with first-order elimination and absorption through three sequential transit compartments best described the data. We assessed that the bio-availability of the 600 mg tablets was 21% higher as the 400 mg tablets, and the bio-availability in pregnant women was 49% lower. Monte-Carlo simulations were performed to predict the pharmacokinetic profile of 1200 mg q.d. in pregnant and nonpregnant women. The primary criteria for efficacy were that the lower bound of the 90% confidence interval (CI) of the concentration before next dose administration (Ctrough ) geometric mean ratio (GMR) of simulated pregnant/nonpregnant women had to be greater than 0.75. The simulated raltegravir Ctrough GMR (90% CI) was 0.51 (0.41-0.63), hence not meeting the primary target for efficacy. Clinical data from two pregnant women using 1200 mg q.d. raltegravir showed a similar Ctrough ratio pregnant/nonpregnant. Our pharmacokinetic results support the current recommendation of not using the raltegravir 1200 mg q.d. regimen during pregnancy until more data on the exposure-response relationship becomes available.

Background Inhaled or nasal corticosteroids can cause suppression of the hypothalamic-pituitary-adrenal (HPA) axis. Early detection is important because this suppression can be associated with significant morbidity. Objective To explore the adverse effect of hypothalamic-pituitary-adrenal suppression by local corticosteroids in HIV-infected patients. Method Ambulatory HIV-infected patients were selected if they used both antiretroviral treatment and inhaled or nasal corticosteroid. Suppression of hypothalamic-pituitary-adrenal axis was defined as a morning plasma cortisol below 80 nmol/L or a cortisol below 550 nmol/L during a 250 mcg adrenocorticotropic hormone-stimulation test. Results Twelve patients were tested; four of them were taking a CYP3A4 inhibitor. All patients had a normal morning plasma cortisol. Suppression of the hypothalamic-pituitary-adrenal axis during the ACTH stimulation test was identified in three of the twelve patients. None of these three individuals were taking a CYP3A4 inhibitor. Conclusion Hypothalamic-pituitary-adrenal axis suppression is frequently identified in patients on inhaled or nasal corticosteroids. CYP3A4 inhibitors such as ritonavir or cobicistat may increase the chance of this adverse effect. In this study we did not identify HPA axis suppression in patients taking CYP3A4 inhibitors. This may be related to the fact that 2 of these 4 patients used beclomethasone, a corticosteroid not metabolized by CYP3A4.ClinicalTrials.gov Identifier NCT02501486.

Bariatric surgery is increasingly applied among people living with HIV to reduce obesity and the associated morbidity and mortality. In people living with HIV, sufficient antiretroviral exposure and activity should always be maintained to prevent development of resistance and disease progression. However, bariatric surgery procedures bring various gastrointestinal modifications including changes in gastric volume, and acidity, gastrointestinal emptying time, enterohepatic circulation and delayed entry of bile acids. These alterations may affect many aspects of antiretroviral pharmacokinetics. Some drug characteristics may result in subtherapeutic exposure and the potential related risk of treatment failure and resistance. Antiretrovirals that require low pH, administration of fatty meals, longer intestinal exposure, and an enterohepatic recirculation for their absorption may be most impacted by bariatric surgery procedures. Additionally, some antiretrovirals can interact with the polyvalent cations in supplements or drugs inhibiting gastric acid, thereby preventing their use as these comedications are commonly prescribed post-bariatric surgery. Predicting pharmacokinetics on the basis of drug characteristics solely proved to be challenging, therefore pharmacokinetic studies remain crucial in this population. Here, we discuss general implications of bariatric surgery on antiretroviral outcomes in people living with HIV as well as drug properties that are relevant for the choice of antiretroviral treatment in this special patient population. Additionally, we summarise studies that evaluated the pharmacokinetics of antiretrovirals post-bariatric surgery. Finally, we performed a comprehensive analysis of theoretical considerations and published pharmacokinetic and pharmacodynamic data to provide recommendations on antiretrovirals for people living with HIV undergoing bariatric surgery.

BCG vaccination and revaccination are increasingly being considered for the protection of adolescents and adults against tuberculosis and, more broadly, for the off-target protective immunological effects against other infectious and noninfectious diseases. Within an international randomized controlled trial of BCG vaccination in healthcare workers (the BRACE trial), we evaluated the incidence of local and serious adverse events, as well as the impact of previous BCG vaccination on local injection site reactions (BCG revaccination). Prospectively collected data from 99% (5351/5393) of participants in Australia, Brazil, Spain, The Netherlands and the UK was available for analysis. Most BCG recipients experienced the expected self-limiting local injection site reactions (pain, tenderness, erythema, swelling). BCG injection site itch was an additional common initial local symptom reported in 49% of BCG recipients. Compared to BCG vaccination in BCG-naïve individuals, BCG revaccination was associated with increased frequency of mild injection site reactions, as well as earlier onset and shorter duration of erythema and swelling, which were generally self-limiting. Injection site abscess and regional lymphadenopathy were the most common adverse events and had a benign course. Self-resolution occurred within a month in 80% of abscess cases and 100% of lymphadenopathy cases. At a time when BCG is being increasingly considered for its off-target effects, our findings indicate that BCG vaccination and revaccination have an acceptable safety profile in adults.

Invasive aspergillosis (IA) is the most prevalent infectious complication in patients with chronic granulomatous disease (CGD). Yet, understanding of fungal pathogenesis in the CGD host remains limited, particularly with regards to A. nidulans infection.

To develop a clinical practice guideline for systemic antifungal prophylaxis in pediatric patients with cancer and hematopoietic stem-cell transplantation (HSCT) recipients.