Fusobacterium necrophorum Meningitis 27 Pediatric Cases From a French National Observatory.

Background: Fusobacterium necrophorum is primarily involved in ear, nose and throat (ENT) infections, and exceptionally causes meningitis. We aimed at describing specific clinical features associated with cases of F. necrophorum meningitis.

Methods: Cases of F. necrophorum meningitis were prospectively collected by a network of 259 pediatric wards covering 60% of French pediatric wards between 2001 and 2024. Children were categorized in 2 groups: "isolated" meningitis and "complicated" meningitis, defined by ≥1 local or systemic complication (mastoiditis, subperiosteal or epidural abscess, Lemierre syndrome).

Results: A total of 27 cases of F. necrophorum meningitis were recorded. Median age was 4 years old (2-7 years) and only 2 were <1 year old. All children had a previous ENT infection, mainly acute otitis media (N = 21/27). Fusobacterium necrophorum was isolated in the cerebrospinal fluid (CSF) by culture (N = 16) or by polymerase chain reaction (PCR) (N = 3). One child had a positive 16S rRNA PCR in a cerebral abscess; other children had a CSF pleocytosis with a positive blood culture. Twenty children had a "complicated" meningitis, while 7 an "isolated" one. Median age was 4 years old in both groups. In the complicated group, 12 children underwent surgical drainage and 4 died. None of these children had a previous medical history.

Conclusions: Our study highlights that, in addition to the well-known Lemierre syndrome, F. necrophorum should be considered in children ≥1 year old presenting with meningitis associated with acute otitis media, particularly when direct CSF examination or usual multiplex PCR fails to identify any bacteria. In such cases, 16S rRNA PCR and antibiotic treatment targeting anaerobic bacteria should be considered.