The global dissemination of hospital clones of Enterococcus faecium.

BACKGROUND: The hospital-adapted A1 group of Enterococcus faecium remains an organism of significant concern in the context of drug-resistant hospital-associated infections. How this pathogen evolves and disseminates remains poorly understood. METHODS: A large, globally representative collection of short-read genomic data from the hospital-associated A1 group of Enterococcus faecium was assembled (n = 973). We analysed, using a novel analysis approach, global diversity in terms of both the dynamics of the accessory genome and homologous recombination among conserved genes. RESULTS: Two main modes of genomic evolution continue to shape E. faecium: the acquisition and loss of genes, including antimicrobial resistance genes, through mobile genetic elements including plasmids, and homologous recombination of the core genome. These events lead to new clones emerging at the local level, followed by the erosion of signals of clonality through recombination, and in some identifiable cases producing new clonal clusters. These patterns lead to new, emerging lineages which are able to spread globally over relatively short timeframes. CONCLUSIONS: The ability of A1 E. faecium to continually present new combinations of genes for potential selection suggests that controlling this pathogen will remain challenging but establishing a framework for understanding genomic evolution is likely to aid in tracking the threats posed by newly emerging lineages

Aetiology of acute respiratory infection in preschool children requiring hospitalisation in Europe-results from the PED-MERMAIDS multicentre case-control study.

BACKGROUND: Both pathogenic bacteria and viruses are frequently detected in the nasopharynx (NP) of children in the absence of acute respiratory infection (ARI) symptoms. The aim of this study was to estimate the aetiological fractions for ARI hospitalisation in children for respiratory syncytial virus (RSV) and influenza virus and to determine whether detection of specific respiratory pathogens on NP samples was associated with ARI hospitalisation. METHODS: 349 children up to 5 years of age hospitalised for ARI (following a symptom-based case definition) and 306 hospital controls were prospectively enrolled in 16 centres across seven European Union countries between 2016 and 2019. Admission day NP swabs were analysed by multiplex PCR for 25 targets. RESULTS: RSV was the leading single cause of ARI hospitalisations, with an overall population attributable fraction (PAF) of 33.4% and high seasonality as well as preponderance in younger children. Detection of RSV on NP swabs was strongly associated with ARI hospitalisation (OR adjusted for age and season: 20.6, 95% CI: 9.4 to 45.3). Detection of three other viral pathogens showed strong associations with ARI hospitalisation: influenza viruses had an adjusted OR of 6.1 (95% CI: 2.5 to 14.9), parainfluenza viruses (PIVs) an adjusted OR of 4.6 (95% CI: 1.8 to 11.3) and metapneumoviruses an adjusted OR of 4.5 (95% CI: 1.3 to 16.1). Influenza viruses had a PAF of 7.9%, PIVs of 6.5% and metapneumoviruses of 3.0%. In contrast, most other pathogens were found in similar proportions in cases and controls, including Streptococcus pneumoniae, which was weakly associated with case status, and endemic coronaviruses. CONCLUSION: RSV is the predominant cause of ARI hospitalisations in young children in Europe and its detection, as well as detection of influenza virus, PIV or metapneumovirus, on NP swabs can establish aetiology with high probability. PAFs for RSV and influenza virus are highly seasonal and age dependent

Targeting a Subpocket in Trypanosoma brucei Phosphodiesterase B1 (TbrPDEB1) Enables the Structure-Based Discovery of Selective Inhibitors with Trypanocidal Activity

Several trypanosomatid cyclic nucleotide phosphodiesterases (PDEs) possess a unique, parasite-specific cavity near the ligand-binding region that is referred to as the P-pocket. One of these enzymes, Trypanosoma brucei PDE B1 (TbrPDEB1), is considered a drug target for the treatment of African sleeping sickness. Here, we elucidate the molecular determinants of inhibitor binding and reveal that the P-pocket is amenable to directed design. By iterative cycles of design, synthesis, and pharmacological evaluation and by elucidating the structures of inhibitor-bound TbrPDEB1, hPDE4B, and hPDE4D complexes, we have developed 4a,5,8,8a-tetrahydrophthalazinones as the first selective TbrPDEB1 inhibitor series. Two of these, 8 (NPD-008) and 9 (NPD-039), were potent (Ki = 100 nM) TbrPDEB1 inhibitors with antitrypanosomal effects (IC50 = 5.5 and 6.7 ?M, respectively). Treatment of parasites with 8 caused an increase in intracellular cyclic adenosine monophosphate (cAMP) levels and severe disruption of T. brucei cellular organization, chemically validating trypanosomal PDEs as therapeutic targets in trypanosomiasis

DNDI-6174 is a preclinical candidate for visceral leishmaniasis that targets the cytochrome bc1.

New drugs for visceral leishmaniasis that are safe, low cost, and adapted to the field are urgently required. Despite concerted efforts over the last several years, the number of new chemical entities that are suitable for clinical development for the treatment of Leishmania remains low. Here, we describe the discovery and preclinical development of DNDI-6174, an inhibitor of Leishmania cytochrome bc1 complex activity that originated from a phenotypically identified pyrrolopyrimidine series. This compound fulfills all target candidate profile criteria required for progression into preclinical development. In addition to good metabolic stability and pharmacokinetic properties, DNDI-6174 demonstrates potent in vitro activity against a variety of Leishmania species and can reduce parasite burden in animal models of infection, with the potential to approach sterile cure. No major flags were identified in preliminary safety studies, including an exploratory 14-day toxicology study in the rat. DNDI-6174 is a cytochrome bc1 complex inhibitor with acceptable development properties to enter preclinical development for visceral leishmaniasis

Integrated dataset of screening hits against multiple neglected disease pathogens.

New chemical entities are desperately needed that overcome the limitations of existing drugs for neglected diseases. Screening a diverse library of 10,000 drug-like compounds against 7 neglected disease pathogens resulted in an integrated dataset of 744 hits. We discuss the prioritization of these hits for each pathogen and the strong correlation observed between compounds active against more than two pathogens and mammalian cell toxicity. Our work suggests that the efficiency of early drug discovery for neglected diseases can be enhanced through a collaborative, multi-pathogen approach

Pharmacokinetics and pharmacodynamics of oral oleylphosphocholine in a hamster model of visceral leishmaniasis

INTRODUCTION Oleylphosphocholine (OlPC) is in the same chemical class as miltefosine (MIL) and was shown to be of superior efficacy and safety at equivalent doses (Fortin et al. 2012; 2014). In the current study, the pharmacokinetic (PK) properties of OlPC were evaluated in hamsters following single oral dose administration. The prophylactic activity of the drug was also explored to establish exposure-activity relationships. Finally, based on knowledge gained on PK, the curative efficacy of a 2× 5 days administration of 20 mg/kg was tested in the context of a longer post-treatment evaluation period. METHODS Female golden hamsters (4-8/group) were administered single oral doses of 20, 50 and 100 mg/kg and blood samples were collected after 2, 6, 24, 32, 72 and 168 h for analysis. For prophylactic studies hamsters (6-7/gr) were given a 100 mg/kg single-dose on day -7, -4, -1 or -4 h prior to infection. The animals were infected on day 0 with 2× 107amastigotes of L. infantum and parasitic burdens were measured in the liver, spleen and bone marrow on day 21. In the curative model, the animals (6/gr) were infected on day 0 and treatment started on day 21. OlPC and MIL were orally dosed at 20 mg/kg for 2× 5 days. Amastigote burdens were determined on day 42 (10 days post end of treatment, dpt) or day 72 (40 dpt). RESULTS OlPC had an elimination t1/2 of ∼l50 hrs and doseproportionality was seen between 20, 50 and 100 mg/kg. A onecompartment disposition model with first-order absorption and elimination fitted best the data. The prophylactic activity of OlPC was in agreement with respective drug exposures, showing dose-dependent residual activity. Interestingly, a 100 mg/kg single dose administered on - 4 day still reduced the overall parasitic burden by ∼l 50%. In the curative model, a ≥99% clearance of the infection was observed at 10 dpt in all OlPCtreated animals and remained the same at 40 dpt. For MIL, a good efficacy was measured at 10 dpt (98, >99 and 90% of reduction in liver, spleen and bone marrow), but the parasite loads had increased at 40 dpt (67, 99 and 79%, respectively), reflecting relapse of the infection and inferiority to OlPC. CONCLUSION This study reveals that total OlPC plasma exposure is a good predictor of the prophylactic and curative efficacy in the hamster VL model. Translated to human, these results suggest that the daily dosing of OlPC will be adjustable to avoid side effects while retaining maximum drug efficacy