Oral microbiota characteristics in children younger than 3 years with febrile seizures: a prospective observational study.

This study investigated the oral microbiota of children younger than 3 years with febrile seizures (FS). Oral swab samples were collected from 48 children with FS and 47 healthy controls, and the V4 region of the bacterial 16 S rRNA gene was sequenced. The Shannon index did not differ significantly between groups, whereas the ACE index was significantly lower in the FS group. Although beta-diversity analysis based on weighted and unweighted UniFrac distances showed no significant between-group differences, partial least squares discriminant analysis provided an exploratory supervised visualization showing apparent separation between the FS and control groups. Among the key genera, Streptococcus, Prevotella, and Granulicatella were significantly enriched in the FS group, whereas Neisseria, Haemophilus, Porphyromonas, and Capnocytophaga were significantly depleted. Predicted functional analysis showed increased relative abundances of pathways related to translation, replication and repair, nucleotide metabolism, cell growth and death, and bacterial infectious diseases, whereas pathways related to energy metabolism, cell motility, signaling molecules and interaction, and transport and catabolism were reduced. These findings suggest that FS is associated with selective ecological reconfiguration of the early-life oral microbiota, mainly reflected by altered proportions of key resident genera.