Epidemiology of Pediatric Bacterial Meningitis in Japan: A Multicenter Survey, 2022-2024.

Abstract

Background: Bacterial meningitis remains a life-threatening condition among infants and young children worldwide, even in the era of advanced antimicrobial therapy and widespread vaccination. As part of ongoing multicenter surveillance in Japan, we investigated the recent epidemiology of pediatric bacterial meningitis during 2022-2024.

Methods: We conducted a multicenter retrospective study of children aged 0-14 years diagnosed with bacterial meningitis in Japan between January 2022 and December 2024. Data were collected using a standardized survey to characterize current epidemiology, age-specific pathogen and pneumococcal serotype patterns, and predictors of poor outcome. Multivariable logistic regression analysis was performed to identify independent predictors of poor outcome.

Results: Of 206 bacterial meningitis cases, 124 (60.2%) were community-acquired and the remaining 82 (39.8%) were healthcare-associated. Eight patients (3.9%) died-four in each group. Streptococcus agalactiae, Escherichia coli, and Streptococcus pneumoniae collectively accounted for 81.5% of community-acquired cases. S. agalactiae predominantly affected neonates and infants up to age 4 months, whereas E. coli was detected from the neonatal period through age 6 months. Among E. coli isolates, 15% (3/20) were extended-spectrum β-lactamase producers. S. pneumoniae was more common after age 4 months; 45.5% (10/22) of isolates were penicillin resistant, and all serotyped isolates were non-PCV13 serotypes. Multivariable analysis identified cerebrospinal fluid glucose level <20 mg/dL as an independent predictor of poor outcome.

Conclusions: This multicenter survey highlights the continued predominance of S. agalactiae, E. coli, and S. pneumoniae as the major causative pathogens of pediatric bacterial meningitis in Japan. Ongoing challenges-including antimicrobial resistance, serotype replacement, and healthcare-associated meningitis-underscore the need for continued surveillance.