Background: Pyomyositis, a bacterial muscle infection, is an important differential diagnosis in children and adolescents with musculoskeletal pain. In contrast to tropical regions, it is rarely recognized in temperate countries, but incidence is increasing and major studies are missing. Methods: This retrospective multicenter study included patients <18 years of age hospitalized with pyomyositis in 11 Swiss children’s hospitals between January 2010 and December 2022. Cases were identified by ICD-10 code (Myositis; M60–M60.9), and data was extracted from electronic hospital records. Results: Of 331 patients identified, 102 fulfilled the case definition. Patient age at presentation ranged from 2 weeks to 17 years (median 8 years). The majority had no underlying illness and all presented with fever and localized pain. At the respective site of pyomyositis, 100 (98%) had impaired movement and 39 (38%) presented with local swelling. Pelvic (57%) and leg (28%) muscles were mostly affected. Blood or tissue cultures were obtained in 94 (92%) and 59 (57%) patients, respectively. Of those, 55 (58%) blood and 52 (88%) tissue cultures were positive, mainly for Staphylococcus aureus (35 and 19, respectively) and Streptococcus pyogenes (12 and 15, respectively). All patients received antibiotic treatment during hospitalization for a median of 10 days (interquartile range: 7–17), followed by outpatient treatment for a further median of 16 days (interquartile range: 11–22) in 95 (93%) patients. Fifty-nine (57%) patients required surgery. Conclusions: Pyomyositis is a challenging diagnosis that requires a high level of awareness. Blood and/or tissue cultures revealed S. aureus and S. pyogenes as the predominant causative agents.

Purpose: Prospective, multicentric observational cohort study in Switzerland investigating measures to prevent mother-to-child transmission in pregnant women with HIV (WWH) and assessing health and development of their exposed children as well as of children with HIV (CWH) in general.Participants: Between January 1986 and December 2022, a total of 1446 mother–child pairs were enrolled. During the same period, the study also registered 187 CWH and 521 HIV-exposed but uninfected children (HEU), for whom detailed maternal information was not available. Consequently, the cohort comprises a total of 2154 children.Findings to date: During these 37 years, research by the Swiss Mother and Child HIV Cohort Study (MoCHiV) and its international collaborators has strongly influenced the prevention of vertical transmission of HIV (eg, introduction and discontinuation of elective caesarean section, neonatal postexposure prophylaxis and breastfeeding). Contributions have also been made to the management of diagnostics (eg, p24 antigen assay) and the effects of antiretroviral treatment (eg, prematurity, growth) in HEU and CWH.Future plans: Most children present within the cohort are now HEU, highlighting the need to investigate other vertically transmitted pathogens such as hepatitis B and C viruses, cytomegalovirus orTreponema pallidum. In addition, analyses are planned on the longitudinal health status of CWH (eg, resistance and prolonged exposure to antiretroviral therapy), on social aspects including stigma in CWH and HEU, and on interventions to further optimise antenatal and postpartum care in WWH.

Enzephalitiden sind eine seltene Manifestation systemischer viraler Infektionen. Die klinischen Zeichen sollten frühzeitig erkannt und supportive Maßnahmen eingeleitet werden. Durch verbesserte diagnostische Möglichkeiten (insbesondere PCR- Untersuchungen) ist die ätiologische Zuordnung einfacher geworden, allerdings sind spezifische therapeutische Möglichkeiten weiterhin beschränkt verfügbar. Der Prävention kommt entscheidende Bedeutung zu. Dies gilt auch für die durch Zecken übertragene FSME. Flaviviren gehören in der Schweiz zu den häufigsten Enzephalitiserregern. Es steht ein wirksamer Impfstoff gegen die FSME-Infektion zur Verfügung.

A Europe-wide outbreak of invasive pediatric group A streptococcal infections (iGAS) began in fall 2022. Here, we report the evolution of GAS hospitalizations in children and adolescents during the second outbreak year in 2023–2024 at a tertiary center in Switzerland. Using prospective monitoring of all in-patient GAS cases below 16 years of age, including those with iGAS, we compared case frequencies and clinical characteristics in three time periods (2013–2020; 2022–2023; 2023–2024). Annual GAS hospitalizations increased from a median of 25 cases (range 11–28) in 2013–2020 to 89 and 63 cases, respectively, in 2022–2023 and 2023–2024. iGAS cases evolved similarly (2013–2020, 4 cases (3–8); 2022–2023, 32 cases; 2023–2024, 21 cases). The decline in cases from 2022–2023 to 2023–2024 included all types of GAS organ involvement, except suppurative infections in the head area, which remained largely unchanged (48 vs. 45 cases). Pleural empyema declined from 13 to 7 cases, possibly explained by a poor overlap of the GAS and influenza curves, respectively, in 2023–2024 compared to 2022–2023. These data document the prolongation of the GAS outbreak into its second winter season in 2023–2024.

Die diagnostischen Möglichkeiten in der Infektiologie haben in den letzten Jahren vor allem durch molekulargenetische Nachweismethoden eine Erweiterung erfahren. Bei der Abklärung von Infektionskrankheiten haben die unterschiedlichen Analysen ihren Stellenwert, wenn diese mit der richtigen Fragestellung zum richtigen Zeitpunkt erfolgen. Jedoch ist nicht jeder positive Befund automatisch auch klinisch relevant beziehungsweise diagnostisch verlässlich. Bei der Beurteilung von Resultaten sind die Grenzen der jeweiligen Analysen zu berücksichtigen. Anhand eines Fallbeispiels einer Patientin mit ‘Fieber ohne Fokus’ sollen im Folgenden Vor- und Nachteile häufiger diagnostischer Methoden in der Infektiologie diskutiert werden.

Les moyens diagnostiques en infectiologie ont connu ces dernières années une expansion grâce notamment aux moyens de détection de la génétique moléculaire. Les différentes analyses ont leur place dans le diagnostic d’une maladie infectieuse, si elles sont effectuées avec la bonne question au bon moment. Tout résultat positif n’est par contre pas nécessairement cliniquement significatif ou un indice diagnostique fiable. Les limites de l’analyse en question doivent être prises en considération lors de l’évaluation d’un résultat.