Relationship between molecular pathogen detection and clinical disease in febrile children across Europe: a multicentre, prospective observational study

BackgroundThe PERFORM study aimed to understand causes of febrile childhood illness by comparing molecular pathogen detection with current clinical practice.MethodsFebrile children and controls were recruited on presentation to hospital in 9 European countries 2016-2020. Each child was assigned a standardized diagnostic category based on retrospective review of local clinical and microbiological data. Subsequently, centralised molecular tests (CMTs) for 19 respiratory and 27 blood pathogens were performed.FindingsOf 4611 febrile children, 643 (14%) were classified as definite bacterial infection (DB), 491 (11%) as definite viral infection (DV), and 3477 (75%) had uncertain aetiology. 1061 controls without infection were recruited. CMTs detected blood bacteria more frequently in DB than DV cases for N. meningitidis (OR: 3.37, 95% CI: 1.92-5.99), S. pneumoniae (OR: 3.89, 95% CI: 2.07-7.59), Group A streptococcus (OR 2.73, 95% CI 1.13-6.09) and E. coli (OR 2.7, 95% CI 1.02-6.71). Respiratory viruses were more common in febrile children than controls, but only influenza A (OR 0.24, 95% CI 0.11-0.46), influenza B (OR 0.12, 95% CI 0.02-0.37) and RSV (OR 0.16, 95% CI: 0.06-0.36) were less common in DB than DV cases. Of 16 blood viruses, enterovirus (OR 0.43, 95% CI 0.23-0.72) and EBV (OR 0.71, 95% CI 0.56-0.90) were detected less often in DB than DV cases. Combined local diagnostics and CMTs respectively detected blood viruses and respiratory viruses in 360 (56%) and 161 (25%) of DB cases, and virus detection ruled-out bacterial infection poorly, with predictive values of 0.64 and 0.68 respectively.InterpretationMost febrile children cannot be conclusively defined as having bacterial or viral infection when molecular tests supplement conventional approaches. Viruses are detected in most patients with bacterial infections, and the clinical value of individual pathogen detection in determining treatment is low. New approaches are needed to help determine which febrile children require antibiotics.FundingEU Horizon 2020 grant 668303

Genomic investigations of unexplained acute hepatitis in children

Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children

Genetic Investigation and Clinical Aspects in a Romanian Treacher Collins Syndrome Family – A Case Report

Introduction: In approximately 96% of probands, the diagnosis of Treacher Collins Syndrome (TCS) is confirmed by molecular genetic tests. These tests can detect heterozygous mutation of TCOF1 gene (coding treacle protein) and variants of POLR1D gene (coding RNA polymerase I subunit D) with autosomal dominant inheritance, or biallelic variants of POLR1C gene (coding RNA polymerase I subunit C) and POLR1D with autosomal recessive inheritance

Pathogenic Biallelic Mutations in ECHS1 in a Case with Short-Chain Enoyl-CoA Hydratase (SCEH) Deficiency-Case Report and Literature Review

ECHS1 gene mutations are known to cause mitochondrial short-chain enoyl-CoA hydratase 1 deficiency, a neurodegenerative disorder characterized by psychomotor development delay, lactic acidosis, and basal ganglia lesions resembling Leigh syndrome. Short-chain enoyl-CoA hydratase 1 (ECHS1) deficiency is a very rare and new disorder, with a wide phenotypic spectrum and different outcomes ranging from neonatal death to survival into adulthood. Since the identification of ECHS1 deficiency in 2014, almost 63 patients with pathogenic mutations in the ECHS1 gene have been described to date. This paper focuses on the clinical and molecular findings as well as the evolution of a Caucasian girl diagnosed with ECHS1 deficiency who carries a new compound heterozygous mutation in the ECHS1 gene. Polymorphic symptoms, namely failure to thrive, significant global developmental delay/regression, movement disorders, ocular abnormalities, hearing loss, seizure, and cardiac myopathy, may be a challenge in mitochondrial disorder suspicion. Early diagnosis, an appropriate diet with valine restriction, and trigger avoidance are essential, as there is no effective therapy for the disease. This disorder influences life quality in these patients and their caregivers, and it has the potential to be fatal

Determining relative proton-proton proximities from the build-up of two-dimensional correlation peaks in H-1 double-quantum MAS NMR: insight from multi-spin density-matrix simulations

The build-up of intensity-as a function of the number, n(rcpl), of POST-C7 elements used for the excitation and reconversion of double-quantum (DQ) coherence (DQC)-is analysed for the fifteen distinct DQ correlation peaks that are observed experimentally for the eight separate 1 H resonances in a H-1 (500 MHz) DQ CRAMPS solid-state (12.5 kHz MAS) NMR spectrum of the dipeptide beta-AspAla (S. P. Brown, A. Lesage, B. Elena, and L. Emsley, J. Am. Chem. Soc., 2004, 126, 13230). The simulation in SPINEVOLUTION (M. Veshtort and R. G. Griffin, J. Magn. Reson., 2006, 178, 248) of t(1) (H-1 DQ evolution) FIDs for clusters of eight dipolar-coupled protons gives separate simulated H-1 DQ build-up curves for the CH2(a), CH2(b), CH(Asp), CH(Ala), NH and OH H-1 single-quantum (SQ) H-1 resonances. An analysis of both the simulated and experimental H-1 DQ build-up leads to the following general observations: (i) considering the build-up of H-1 DQ peaks at a particular SQ frequency, maximum intensity is observed for the DQC corresponding to the shortest H-H distance; (ii) for the maximum intensity H-1 DQ peak at a particular SQ frequency, the recoupling time for the observed maximum intensity depends on the corresponding H-H distance, e. g., maximum intensity for the CH2(a)-CH2(b) (H-H distance = 1.55 angstrom) and OH-CH(Asp) (H-H distance = 2.49 angstrom) DQ peaks is observed at nrcpl = 2 and 3, respectively; (iii) for DQ peaks involving a CH2 proton at a non-CH2 SQ frequency, there is much reduced intensity and a maximum intensity at a short recoupling time; (iv) for the other lower intensity H-1 DQ peaks at a particular SQ frequency, maximum intensity is observed for the same (or close to the same) recoupling time, but the relative intensity of the DQ peaks is a reliable indicator of the relative H-H distance-the ratio of the maximum intensities for the peaks at the CH(Ala) SQ frequency due to the two DQCs with the NH and OH protons are found to be approximately in the ratio of the squares of the corresponding dipolar coupling constants. While the simulated H-1 DQ build-up curves reproduce most of the features of the experimental curves, maximum intensity is often observed at a longer recoupling time in simulations. In this respect, simulations for two to eight spins show a trend towards a faster decay for an increasing number of considered spins. Finally, simulations show that increasing either the Larmor frequency (to 1 GHz) or the MAS frequency (to 125 kHz) does not lead to changes in the marked differences between the H-1 DQ build-up curves at the CH(Asp) SQ frequency for DQCs to the CH2(a) and OH protons that correspond to similar H-H distances (2.39 angstrom and 2.49 angstrom, respectively)

Thermal Effusivity Investigations of Solid Thermoelectrics Using the Front Photopyroelectric Detection

The front photopyroelectric configuration (FPPE), making use of air as a coupling fluid between the sample and sensor, was applied to measure the thermal effusivity of some solid thermoelectric materials. The investigated samples were ZnO, CuCrO2, Cu4Sn7S16, TiS3 and two samples of high manganese silicide (HMS) thermoelectric materials. Most of these materials are porous and consequently, the classical PPE method, making use of standard coupling fluids between sensor and sample, cannot be used due to the fact that the coupling fluid penetrates inside the sample and leads to incorrect results. With this work we extend (to thermoelectric solids) the area of application of a method, recently proposed by Salazar et al. (Measurement 121: 96, 2018). Experimentally, the thermal effusivity is obtained from a multi-parametric fit of the phase of the FPPE signal as a function of the modulation frequency (with sample’s thermal effusivity, thickness of the sensor-sample air gap and heat losses by convection and radiation, as fitting parameters). It was demonstrated that, in some particular cases, the three parameters are independent and consequently, the solution of the fit is unique. Where possible, the obtained results have been compared with data from the literature and good agreement was found

Improved Photopyroelectric (PPE) Configuration for Thermal Effusivity Investigations of Porous Solids

A new photopyroelectric detection configuration is proposed in order to measure the thermal effusivity of porous solids. Compared with the previously reported detection scheme this configuration makes use of a transparent window in front of the pyroelectric sensor. In such a way, the heat losses by convection at the sensor’s irradiated surface are eliminated, and consequently, the conduction remains the only process responsible for the heat propagation in the whole detection cell. In the paper, the mathematical model for this new configuration is developed, with the main conclusion that the sample’s thermal effusivity can be finally obtained via a fitting procedure with only two fitting parameters (instead of three as previously reported); in such a way, the possible degeneracy of the results is eliminated. The suitability of the method is demonstrated with application on some porous building materials and cellulose-based pressed powders

CHHC and H-1-H-1 magnetization exchange: analysis by experimental solid-state NMR and 11-spin density-matrix simulations

A protocol is presented for correcting the effect of non-specific cross-polarization in CHHC solid-state MAS NMR experiments, thus allowing the recovery of the H-1-H-1 magnetization exchange functions front the mixing-time dependent buildup of experimental CHHC peak intensity. The presented protocol also incorporates a Scaling Procedure to take into account the effect Of multiplicity of a CH2 or CH3 moiety. Experimental CHHC buildup Curves are presented for L-tyrosine center dot HCl samples where either all OF only one in 10 molecules are U-C-13 labeled. Good agreement between experiment and 11-spin SPINEVOLUTION simulation (including only isotropic H-1 chemical shifts) is demonstrated for the initial buildup (t(mix) < 100 mu s) of CHHC peak intensity corresponding to an intramolecular close (2.5 degrees) H-H proximity. Differences in the initial CHHC buildup are observed between the one in 10 dilute and 100% samples for cases where there is a close intermolecular H-H proximity in addition to a close intramolecular H-H proximity. For the dilute sample, CHHC cross-peak intensities tended to significantly lower values for long mixing times (500 mu s) as compared to the 100% sample. This difference is explained as being due to the dependence of the limiting total magnetization on the ratio N-obs/N-tot between the number of protons that are directly attached to a C-13 nucleus and hence contribute significantly to the observed C-13 CHHC NMR signal, and the total number of H-1 spins into the system. H-1-H-1 magnetization exchange Curves extracted from CHHC spectra for the 100% L-tyrosine HCI sample exhibit a clear sensitivity to the root sum squared dipolar coupling, with fast buildup being observed for the shortest intramolecular distances (2.5 angstrom) and slower, yet observable buildup for the longer intermolecular distances (up to 5 angstrom). (C) 2009 Elsevier Inc. All rights reserved