Listeria monocytogenes meningitis beyond the neonatal period: a multicenter case series of previously unpublished pediatric cases from Türkiye.

Pediatric Listeria monocytogenes meningitis beyond the neonatal period is rare and poorly characterized; we aimed to describe previously unpublished cases from Türkiye. In this multicenter retrospective case series (2015-2025), children 1 month-18 years with compatible clinical and cerebrospinal fluid (CSF) findings and microbiologically confirmed L. monocytogenes meningitis (CSF culture/PCR or blood culture with compatible CSF findings) were included. Previously published or concurrently submitted cases were excluded. Outcomes were assessed using the Glasgow Outcome Scale (GOS). Eleven previously unpublished patients (6 M/5F; median age 49 months, IQR 15.5-74.5) were included. CSF culture was positive in 10/11 (90.9%); CSF PCR was performed in 9 patients and confirmed the diagnosis in all, including one with negative culture. Blood cultures were positive in 3/11 (27.3%). Fever, altered consciousness (90.9%), and meningeal signs (81.8%) predominated. Four (36.4%) had immune-related conditions: MHC class I deficiency, T-cell acute lymphoblastic leukemia, juvenile dermatomyositis on immunosuppression, and Crohn disease; six (54.5%) had no underlying disorder, and one had a non-immune condition (osteogenesis imperfecta). Ampicillin-based therapy was used in 10/11 (90.9%), with meropenem (81.8%). Mortality was 18.2%; another 18.2% had severe sequelae requiring ventriculoperitoneal shunt. Unfavorable outcomes (GOS 1-3) were nominally associated with seizures, respiratory failure, hypokalemia, and lower leukocyte counts; none was significant after Bonferroni correction.Conclusion: In this multicenter series of previously unpublished pediatric cases from Türkiye, L. monocytogenes meningitis carried substantial morbidity and mortality. Early Listeria consideration in cephalosporin-unresponsive meningitis, ampicillin-based therapy, CSF PCR, and pediatric immunology referral should be considered. What is Known: • L. monocytogenes is cephalosporin-resistant; post-neonatal pediatric data are limited to small series and case reports What is New: • In 11 Turkish children, mortality and severe sequelae were each 18.2%. • One case had an ampicillin-resistant isolate; another mimicked autoimmune limbic encephalitis radiologically, illustrating diagnostic overlap. • Unfavorable outcomes (GOS 1-3) were nominally associated with seizures, respiratory failure, hypokalemia, and lower leukocyte counts;however, none remained significant after Bonferroni correction.