Epidemiology of pediatric meningitis and encephalitis in Japan: a cross-sectional study

Information on the epidemiology and cause-specific clinical features of pediatric meningitis and encephalitis is limited, owing to conventional laboratory methods' limitations in identifying causative pathogens. The FilmArray Meningitis/Encephalitis (FA-M/E) panel, a molecular diagnostic tool, can detect 14 pathogens within 1 hour. We investigated meningitis and encephalitis epidemiology among children in Japan and FA-M/E panels' utility in their clinical management. This cross-sectional study was conducted among children aged 0-18 years admitted to seven regional hospitals in western Japan between October 2022 and September 2023. Cerebrospinal fluid (CSF) samples were collected from 221 children and tested using the FA-M/E panel. Clinical and microbiological data were reviewed retrospectively. Fifty-eight patients tested positive using the FA-M/E panel. Viral and bacterial pathogens were detected in 49 and nine cases, respectively. Human parechovirus and enterovirus occurred mainly in epidemic clusters during the summer and were primarily detected in young infants. Patients who tested positive for human parechovirus had a significantly higher frequency of sepsis-like manifestations and a lower frequency of CSF pleocytosis than did those who tested positive for enterovirus. CSF pleocytosis was absent in 30 patients who tested positive using the FA-M/E panel. Among the patients who tested positive for bacteria, three of the nine were not diagnosed using conventional culture methods, owing to prior antimicrobial therapy. The FA-M/E panel can identify bacterial and viral pathogens causing pediatric meningitis and characterize the epidemiology in local communities.IMPORTANCECulture and polymerase chain reactions have traditionally been used to identify microorganisms causing pediatric meningitis and encephalitis. However, the methods currently used to identify the causative microorganisms are limited, particularly in general hospitals. The FilmArray Meningitis/Encephalitis (FA-M/E) panel, a fully automated genetic testing system, can detect 14 pathogens using the multiplex polymerase chain reaction method. This study described the epidemiology of pediatric meningitis and encephalitis in Japan. The microorganisms causing acute meningitis and encephalitis in children in Japan were identified using the FilmArray Meningitis/Encephalitis panel. Testing cerebrospinal fluid using the FA-M/E panel is useful for the identification of the pathogen in children with community-acquired acute meningitis and encephalitis. This increases knowledge on the epidemiology and clinical manifestations of acute meningitis and encephalitis caused by specific pathogens and can be used to facilitate optimal patient management.