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Query: "author" (Veronika Osterman) .

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1.
A multi-platform approach to identify a blood-based host protein signature for distinguishing between bacterial and viral infections in febrile children (PERFORM) : a multi-cohort machine learning study
Heather R. Jackson, Judith Zandstra, Stephanie Menikou, Melissa Shea Hamilton, Andrew J McArdle, Roman Fischer, Adam M Thorne, Marko Pokorn, 2023, original scientific article

Abstract: Background: Differentiating between self-resolving viral infections and bacterial infections in children who are febrile is a common challenge, causing difficulties in identifying which individuals require antibiotics. Studying the host response to infection can provide useful insights and can lead to the identification of biomarkers of infection with diagnostic potential. This study aimed to identify host protein biomarkers for future development into an accurate, rapid point-of-care test that can distinguish between bacterial and viral infections, by recruiting children presenting to health-care settings with fever or a history of fever in the previous 72 h. Methods: In this multi-cohort machine learning study, patient data were taken from EUCLIDS, the Swiss Pediatric Sepsis study, the GENDRES study, and the PERFORM study, which were all based in Europe. We generated three high-dimensional proteomic datasets (SomaScan and two via liquid chromatography tandem mass spectrometry, referred to as MS-A and MS-B) using targeted and untargeted platforms (SomaScan and liquid chromatography mass spectrometry). Protein biomarkers were then shortlisted using differential abundance analysis, feature selection using forward selection-partial least squares (FS-PLS; 100 iterations), along with a literature search. Identified proteins were tested with Luminex and ELISA and iterative FS-PLS was done again (25 iterations) on the Luminex results alone, and the Luminex and ELISA results together. A sparse protein signature for distinguishing between bacterial and viral infections was identified from the selected proteins. The performance of this signature was finally tested using Luminex assays and by calculating disease risk scores. Findings: 376 children provided serum or plasma samples for use in the discovery of protein biomarkers. 79 serum samples were collected for the generation of the SomaScan dataset, 147 plasma samples for the MS-A dataset, and 150 plasma samples for the MS-B dataset. Differential abundance analysis, and the first round of feature selection using FS-PLS identified 35 protein biomarker candidates, of which 13 had commercial ELISA or Luminex tests available. 16 proteins with ELISA or Luminex tests available were identified by literature review. Further evaluation via Luminex and ELISA and the second round of feature selection using FS-PLS revealed a six-protein signature: three of the included proteins are elevated in bacterial infections (SELE, NGAL, and IFN-gamma), and three are elevated in viral infections (IL18, NCAM1, and LG3BP). Performance testing of the signature using Luminex assays revealed area under the receiver operating characteristic curve values between 89 center dot 4% and 93 center dot 6%. Interpretation: This study has led to the identification of a protein signature that could be ultimately developed into a blood-based point-of-care diagnostic test for rapidly diagnosing bacterial and viral infections in febrile children. Such a test has the potential to greatly improve care of children who are febrile, ensuring that the correct individuals receive antibiotics.
Keywords: C-reactive protein, antibiotic overuse, virus-infection, resistance
Published in DiRROS: 10.03.2026; Views: 394; Downloads: 282
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Febrile illness in high-risk children : a prospective, international observational study
Fabian Johannes Stanislaus Van der Velden, Gabriella De Vries, Alexander James Martin, Emma Lim, Ulrich Von Both, Laura Kolberg, Enitan D Carrol, Aakash Khanijau, Marko Pokorn, 2023, original scientific article

Abstract: To assess and describe the aetiology and management of febrile illness in children with primary or acquired immunodeficiency at high risk of serious bacterial infection, as seen in emergency departments in tertiary hospitals. Prospective data on demographics, presenting features, investigations, microbiology, management, and outcome of patients within the 'Biomarker Validation in HR patients' database in PERFORM, were analysed. Immunocompromised children (< 18 years old) presented to fifteen European hospitals in nine countries, and one Gambian hospital, with fever or suspected infection and clinical indication for blood investigations. Febrile episodes were assigned clinical phenotypes using the validated PERFORM algorithm. Logistic regression was used to assess the effect size of predictive features of proven/presumed bacterial or viral infection. A total of 599 episodes in 482 children were analysed. Seventy-eight episodes (13.0%) were definite bacterial, 67 episodes probable bacterial (11.2%), and 29 bacterial syndrome (4.8%). Fifty-five were definite viral (9.2%), 49 probable viral (8.2%), and 23 viral syndrome (3.8%). One hundred ninety were unknown bacterial or viral infections (31.7%), and 108 had inflammatory or other non-infectious causes of fever (18.1%). Predictive features of proven/presumed bacterial infection were ill appearance (OR 3.1 (95% CI 2.1-4.6)) and HIV (OR 10.4 (95% CI 2.0-54.4)). Ill appearance reduced the odds of having a proven/presumed viral infection (OR 0.5 ( 95% CI 0.3-0.9)). A total of 82.1% had new empirical antibiotics started on admission (N = 492); 94.3% proven/presumed bacterial (N = 164), 66.1% proven/presumed viral (N = 84), and 93.2% unknown bacterial or viral infections (N = 177). Mortality was 1.9% (N = 11) and 87.1% made full recovery (N = 522). Conclusion: The aetiology of febrile illness in immunocompromised children is diverse. In one-third of cases, no cause for the fever will be identified. Justification for standard intravenous antibiotic treatment for every febrile immunocompromised child is debatable, yet effective. Better clinical decision-making tools and new biomarkers are needed for this population.
Keywords: immunocompromised, paediatric, children, fever, infection, antibiotics
Published in DiRROS: 21.11.2025; Views: 568; Downloads: 360
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4.
Emergency medical services utilisation among febrile children attending emergency departments across Europe : an observational multicentre study
Chantal D. Tan, Clementien L. Vermont, Joany M. Zachariasse, Ulrich Von Both, Irini Eleftheriou, Marieke Emonts, Michiel Van der Flier, Jethro Adam Herberg, Marko Pokorn, 2023, original scientific article

Abstract: Children constitute 6–10% of all patients attending the emergency department (ED) by emergency medical services (EMS). However, discordant EMS use in children occurs in 37–61% with fever as an important risk factor. We aimed to describe EMS utilisation among febrile children attending European EDs. This study is part of an observational multicentre study assessing management and outcome in febrile children up to 18 years (MOFICHE) attending twelve EDs in eight European countries. Discordant EMS use was defined as the absence of markers of urgency including intermediate/high triage urgency, advanced diagnostics, treatment, and admission in children transferred by EMS. Multivariable logistic regression analyses were performed for the association between (1) EMS use and markers of urgency, and (2) patient characteristics and discordant EMS use after adjusting all analyses for the covariates age, gender, visiting hours, presenting symptoms, and ED setting. A total of 5464 (15%, range 0.1–42%) children attended the ED by EMS. Markers of urgency were more frequently present in the EMS group compared with the non-EMS group. Discordant EMS use occurred in 1601 children (29%, range 1–59%). Age and gender were not associated with discordant EMS use, whereas neurological symptoms were associated with less discordant EMS use (aOR 0.2, 95%CI 0.1–0.2), and attendance out of office hours was associated with more discordant EMS use (aOR 1.6, 95%CI 1.4–1.9). Settings with higher percentage of self-referrals to the ED had more discordant EMS use (p < 0.05). Conclusion: There is large practice variation in EMS use in febrile children attending European EDs. Markers of urgency were more frequently present in children in the EMS group. However, discordant EMS use occurred in 29%. Further research is needed on non-medical factors influencing discordant EMS use in febrile children across Europe, so that pre-emptive strategies can be implemented.
Keywords: emergency medical services, emergency care, children, fever, paediatrics
Published in DiRROS: 17.11.2025; Views: 657; Downloads: 348
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5.
Relationship between molecular pathogen detection and clinical disease in febrile children across Europe : a multicentre, prospective observational study
Priyen Shah, Marie Voice, Leonides Calvo-Bado, Irene Rivero Calle, Sophie Morris, Ruud Nijman, Claire Broderick, Tisham De, Mojca Kolnik, Katarina Vincek, Marko Pokorn, 2023, original scientific article

Abstract: Background: The PERFORM study aimed to understand causes of febrile childhood illness by comparing molecular pathogen detection with current clinical practice. Methods: Febrile 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. Findings: Of 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. Interpretation: Most 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.
Keywords: molecular diagnostics, diagnostic, febrile illness, infectious disease, bacterial infection, viral infection, respiratory infection
Published in DiRROS: 17.11.2025; Views: 641; Downloads: 373
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6.
Raising AWaRe-ness of antimicrobial stewardship challenges in pediatric emergency care : results from the PERFORM study assessing consistency and appropriateness of antibiotic prescribing across Europe
Laura Kolberg, Aakash Khanijau, Fabian Johannes Stanislaus Van der Velden, Jethro Adam Herberg, Tisham De, Rachel Galassini, Aubrey J. Cunnington, Victoria J. Wright, Marko Pokorn, Mojca Kolnik, 2024, original scientific article

Abstract: Background: Optimization of antimicrobial stewardship is key to tackling antimicrobial resistance, which is exacerbated by overprescription of antibiotics in pediatric emergency departments (EDs). We described patterns of empiric antibiotic use in European EDs and characterized appropriateness and consistency of prescribing. Methods: Between August 2016 and December 2019, febrile children attending EDs in 9 European countries with suspected infection were recruited into the PERFORM (Personalised Risk Assessment in Febrile Illness to Optimise Real-Life Management) study. Empiric systemic antibiotic use was determined in view of assigned final “bacterial” or “viral” phenotype. Antibiotics were classified according to the World Health Organization (WHO) AWaRe classification. Results: Of 2130 febrile episodes (excluding children with nonbacterial/nonviral phenotypes), 1549 (72.7%) were assigned a bacterial and 581 (27.3%) a viral phenotype. A total of 1318 of 1549 episodes (85.1%) with a bacterial and 269 of 581 (46.3%) with a viral phenotype received empiric systemic antibiotics (in the first 2 days of admission). Of those, the majority (87.8% in the bacterial and 87.0% in the viral group) received parenteral antibiotics. The top 3 antibiotics prescribed were thirdgeneration cephalosporins, penicillins, and penicillin/β-lactamase inhibitor combinations. Of those treated with empiric systemic antibiotics in the viral group, 216 of 269 (80.3%) received ≥1 antibiotic in the “Watch” category. Conclusions: Differentiating bacterial from viral etiology in febrile illness on initial ED presentation remains challenging, resulting in a substantial overprescription of antibiotics. A significant proportion of patients with a viral phenotype received systemic antibiotics, predominantly classified as WHO Watch. Rapid and accurate point-of-care tests in the ED differentiating between bacterial and viral etiology could significantly improve antimicrobial stewardship.
Keywords: antimicrobial stewardship, pediatric emergency care, antibiotic prescription, AWaRe, infectious diseases
Published in DiRROS: 17.11.2025; Views: 480; Downloads: 381
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7.
Guideline adherence in febrile children below 3 months visiting European Emergency Departments : an observational multicenter study
Chantal D. Tan, Eline E. P. L. van der Walle, Clementien L. Vermont, Ulrich Von Both, Enitan D Carrol, Irini Eleftheriou, Marieke Emonts, Michiel Van der Flier, Ronald De Groot, Marko Pokorn, 2022, original scientific article

Abstract: Febrile children below 3 months have a higher risk of serious bacterial infections, which often leads to extensive diagnostics and treatment. There is practice variation in management due to differences in guidelines and their usage and adherence. We aimed to assess whether management in febrile children below 3 months attending European Emergency Departments (EDs) was according to the guidelines for fever. This study is part of the MOFICHE study, which is an observational multicenter study including routine data of febrile children (0–18 years) attending twelve EDs in eight European countries. In febrile children below 3 months (excluding bronchiolitis), we analyzed actual management compared to the guidelines for fever. Ten EDs applied the (adapted) NICE guideline, and two EDs applied local guidelines. Management included diagnostic tests, antibiotic treatment, and admission. We included 913 children with a median age of 1.7 months (IQR 1.0–2.3). Management per ED varied as follows: use of diagnostic tests 14–83%, antibiotic treatment 23–54%, admission 34–86%. Adherence to the guideline was 43% (374/868) for blood cultures, 29% (144/491) for lumbar punctures, 55% (270/492) for antibiotic prescriptions, and 67% (573/859) for admission. Full adherence to these four management components occurred in 15% (132/868, range 0–38%), partial adherence occurred in 56% (484/868, range 35–77%). Conclusion: There is large practice variation in management. The guideline adherence was limited, but highest for admission which implies a cautious approach. Future studies should focus on guideline revision including new biomarkers in order to optimize management in young febrile children.
Keywords: fever, children, pediatrics, guideline, emergency care
Published in DiRROS: 17.11.2025; Views: 539; Downloads: 268
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8.
Impact of infection on proteome-wide glycosylation revealed by distinct signatures for bacterial and viral pathogens
Esther Willems, Jolein Gloerich, Anouk Suppers, Michiel Van der Flier, 2023, original scientific article

Abstract: Mechanisms of infection and pathogenesis have predominantly been studied based on differential gene or protein expression. Less is known about posttrans-lational modifications, which are essential for protein functional diversity. We applied an innovative glycoproteomics method to study the systemic prote-ome-wide glycosylation in response to infection. The protein site-specific glyco-sylation was characterized in plasma derived from well-defined controls and patients. We found 3862 unique features, of which we identified 463 distinct intact glycopeptides, that could be mapped to more than 30 different proteins. Statistical analyses were used to derive a glycopeptide signature that enabled significant differentiation between patients with a bacterial or viral infection. Furthermore, supported by a machine learning algorithm, we demonstrated the ability to identify the causative pathogens based on the distinctive host blood plasma glycopeptide signatures. These results illustrate that glycoproteomics holds enormous potential as an innovative approach to improve the interpreta-tion of relevant biological changes in response to infection.
Keywords: plasma, roles, glycoproteomics, biomarkers, profiles, children, glycome
Published in DiRROS: 17.11.2025; Views: 529; Downloads: 323
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9.
Safety, long-term effectiveness, and immunogenicity of varicella vaccination in children with juvenile idiopathic arthritis treated with biologic therapy
Maša Bizjak, Jakob Peterlin, Tadej Avčin, Miroslav Petrovec, Alojz Ihan, Mojca Zajc Avramovič, Gašper Markelj, Tina Vesel, Veronika Osterman, Jerneja Ahčan, Helena Mole, Katja Dejak Gornik, Alenka Biteznik, Sara Jevnikar, Larisa Janžič, Miha Bajc, Andreja Nataša Kopitar, Nataša Toplak, 2025, original scientific article

Abstract: Objective: To evaluate safety, long-term effectiveness and immunogenicity of varicella vaccination in children with JIA, treated with biologic disease-modifying antirheumatic drugs (bDMARDs). Methods: This is a prospective case-control study. VZV-naive patients with JIA on selected bDMARDs (TNFi, IL-6 and IL-1 inhibitors), who were at risk for contracting varicella, had stable disease and normal values of immunoglobulins and lymphocyte populations, were vaccinated against varicella. Adverse events (AEs) and disease activity were followed after vaccination. VZV-specific humoral (VZV-IgG) and cell-mediated immunity (VZV-CMI) were measured at predetermined time points after vaccination by Liaison and intracellular cytokine staining, respectively. Two healthy control (HC) groups comprised 52 healthy children after varicella vaccination and 69 healthy children after varicella infection. Results: 17 patients were vaccinated against varicella (12 on TNFi, 4 on IL-6 inhibitors and 1 on IL-1 inhibitor), of whom 14 patients received both the first and second dose on bDMARDs. No vaccine-strain infections or other serious AEs occurred after vaccination. Disease activity increased in 3/17 (18 %) patients following vaccination. Four out of 17 (24 %) patients developed mild breakthrough varicella (BV) 4 months-4.5 years after vaccination, and none of the HC. Fourteen out of 17 (82 %) patients and 50/52 (96 %) vaccinated HC were seropositive after second vaccination and 8/11 (72 %) patients and 42/43 (98 %) vaccinated HC developed VZV-CMI, which persisted longer compared to VZV-IgG. Patients presented lower antibody levels compared to HC. The rate of VZV-IgG decline was comparable between patients and HC after vaccination or infection. Five patients received the third vaccine dose due to primary or secondary vaccine failure, and none of them developed BV. Conclusions: Varicella vaccination was safe and largely immunogenic in our cohort of JIA patients treated with bDMARDs. Although the vaccination was not always fully effective, it prevented severe disease in all vaccinated patients.
Keywords: varicella vaccination, juvenile idiopathic arthritis, biologic therapy, anti-cytokine therapy
Published in DiRROS: 13.11.2025; Views: 583; Downloads: 349
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