Altered gut microbiome composition in children with refractory epilepsy after ketogenic diet

The aim of this study was to investigate the characteristics and composition of intestinal microbiota in children with refractory epilepsy after ketogenic diet (KD) therapy and to explore the bacterial biomarkers related to clinical efficacy.We prospectively analyzed 20 patients (14 males, 6 females) treated with KD. Clinical efficacy, electroencephalogram (EEG) changes, and laboratory tests were evaluated, and fecal specimens were obtained prior to and 6 months after therapy. The composition of gut microbiota was analyzed by 16S rDNA sequencing, and we screened the possible flora associated with efficacy of the KD.After 6 months of treatment, 2 patients were seizure free, 3 had ≥ 90% seizure reduction, 5 had a reduction of 50-89%, and 10 had < 50% reduction. All 10 responders showed an improvement in EEG. Compared with baseline, fecal microbial profiles showed lower alpha diversity after KD therapy and revealed significantly decreased abundance of Firmicutes and increased levels of Bacteroidetes. We also observed that Clostridiales, Ruminococcaceae, Rikenellaceae, Lachnospiraceae, and Alistipes were enriched in the non-responsive group.The results show that the KD can reduce the species richness and diversity of intestinal microbiota. The changes of gut microbiota may be associated with different efficacy after KD, and specific gut microbiota may serve as an efficacy biomarker and a potential therapeutic target in patients with refractory epilepsy.