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The comparison of gut microbiota between different types of epilepsy in children
Microbial Cell Factories volume 24, Article number: 64 (2025)
Abstract
Objective
To better understand the variations in gut microbiota in children with different types of epilepsy.
Methods
Thirty-seven children with epilepsy were included in the case group, which was further divided into focal (group A, n = 28) and generalized epilepsy groups (group B, n = 9) based on the origin and extent of the seizures. The focal epilepsy group was subdivided into the benign childhood epilepsy with centrotemporal spikes (BECT) (group C, n = 9) and non-BECT groups (group D, n = 19) based on the appearance of typical centrotemporal spikes or spike-wave complexes on the electroencephalogram (EEG). Additionally, 14 healthy children were selected as the control group (group E, n = 14).
Results
Significant differences were observed in the diversity and composition of gut microbiota between the case and control groups. At the genus level, the abundance of Megamonas (P = 0.001), Streptococcus (P<0.001), Romboutsia (P = 0.001), Bacteroides (P<0.05), and Escherichia/Shigella (P<0.05) was significantly higher in the focal epilepsy group than in the control group (0.027 vs. 0.00009, P = 0.001; 0.016 vs. 0.002, P<0.001; 0.013 vs. 0.002, P = 0.001; 0.030 vs. 0.002, P<0.05, respectively). Additionally, Escherichia/Shigella (P<0.05) was more abundant in the case group compared to the control group (0.033 vs. 0.002, P<0.05). Bacteroides (P<0.05) was more abundant in the control group than in the case group. Megamonas (P<0.001) and Collinsella (P<0.05) were significantly more prevalent in the BECT group than in the control group (0.034 vs. 0.00009, P<0.001; 0.014 vs. 0.001, P<0.05, respectively). In the non-BECT group, compared to the control group, Megamonas (P = 0.013), Streptococcus (P<0.001), Romboutsia (P = 0.001), and Escherichia/Shigella (P<0.05) were found in greater abundance (0.023 vs. 0.00009, P = 0.013; 0.018 vs. 0.002, P<0.001; 0.014 vs. 0.002, P = 0.001; 0.037 vs. 0.002, P<0.05, respectively).
Conclusions
Though, there were no statistically significant differences in gut microbiota between the different types of epilepsy, the gut microbiota of children with epilepsy significantly differed from that of healthy controls. The increased abundance of Escherichia/Shigella may lead to the worsening of clinical phenotypes and poor prognosis, and it could be a candidate biomarker to identify the focal epilepsy or even non-benign childhood epilepsy with centrotemporal spikes, potentially providing new therapeutic targets for the future.
Introduction
The incidence of epilepsy in children ranges from 41 per 100,000 to 187 per 100,000, with higher prevalence observed in developing countries. It has been reported that the incidence is highest during the first 12 months of life and gradually decreases to adult levels by the end of the first decade. According to the most recent classification of epilepsy syndromes, only about one-third of children with epilepsy can be assigned to a specific epilepsy syndrome [1,2,3]. The basic version of the International League Against Epilepsy (ILAE) classification of seizure types categorizes the onset of a seizure as follows: (1) focal, (2) generalized, (3) unknown, or (4) unclassifiable [4]. Focal and generalized seizures also encompass specific types of epilepsy, known as epilepsy syndromes, in which seizure types, electroencephalogram (EEG) findings, and imaging features tend to appear together in the same individual. Examples include infantile spasms, childhood aphasic epilepsy, and benign childhood epilepsy with centrotemporal spikes (BECT). BECT is the most common epilepsy syndrome in children with focal epilepsy, accounting for 14-17% of pediatric epilepsy cases. It has a minimal impact on brain function and is often capable of spontaneous remission [5]. Approximately 30% of patients cannot be effectively treated with clinical medications. This condition is referred to as drug-resistant epilepsy (DRE) [6]. DRE does not now have a uniform or unique definition. It generally refers to a country with insufficient seizure control that renders probably fantastic antiepileptic drugs (AEDs) ineffective at tolerable ranges for 1–2 years and is especially characterized by non-epidemic activities and negative adherence [7]. The pathogenesis of epilepsy is believed to be closely linked to ion channels, neurotransmitter imbalances, genetics, and immunity. However, the exact mechanisms are more complex and not yet fully understood [8]. Moreover, more severe seizures, such as focal secondary bilateral tonic-clonic seizures, may occur following focal seizures. Uncontrolled seizures caused by epilepsy can impair children’s growth and development by leading to cognitive deficits and long-term brain dysfunction [9].
Recently, researchers have shown increased interest in gut microbiota. The gut-brain axis, which controls neuronal networks, neuroendocrine, immune, and inflammatory pathways to regulate both intestinal homeostasis and the central nervous system, is a bidirectional communication between the gut and the brain. Advances in sequencing technology have highlighted the crucial regulatory role of the intestinal microbiota in various neurological diseases, such as Parkinson’s disease [10], Alzheimer’s disease [11], and multiple sclerosis [10], and multiple sclerosis [12]. While people with inflammatory bowel disease are more likely to develop epilepsy, individuals with epilepsy often experience gastrointestinal symptoms [13]. Recent research has linked changes in the gut microbiota to epilepsy. It has been found that there are differences in the gut microbiota between people with epilepsy and healthy individuals. Xie et al. [14] discovered a significant decrease in Aspergillus and an increase in Bacteroides fragilis in infants with refractory epilepsy compared to healthy children.
Several studies have investigated the gut microbiota of individuals with refractory epilepsy, but none have focused on the gut microbiota of patients with different seizure types of epilepsy, especially those with epileptic syndromes. Therefore, this study aimed to examine the gut microbiota of children with different seizure types of epilepsy and healthy children using high-throughput sequencing technology. Specifically, the study had two main objectives: (1) Compare and analyze the gut microbiota and its differences between different types of epilepsy and healthy children. (2) Compare and analyze the gut microbiota and its differences between different types of epilepsy. (3) Identify new therapeutic targets for epilepsy.
Materials and methods
Study subjects
A total of 37 children with newly diagnosed focal epilepsy, hospitalized in the Neurology Department of Hunan Children’s Hospital (Changsha, China) between April 2020 and December 2020, were enrolled as the case group (Fig. 1). The diagnostic criteria for focal epilepsy were based on the ILAE 2017 guidelines [15]. Inclusion criteria were age over two years, electroencephalogram and clinical findings supporting the diagnosis of focal epilepsy, no previous abnormalities on head Magnetic Resonance Imaging, and no family history of epilepsy. Exclusion criteria were the use of specific diets, chronic or acute gastrointestinal disorders, and the use of antibiotics or probiotics within two weeks of either of the two collection time points. The case group was then divided into the focal epilepsy group (n = 28) and the generalized epilepsy group (n = 9), with the focal epilepsy group further subdivided into the BECT group (n = 9) and the non-BECT group (n = 19).
Fourteen mentally and physically healthy children of similar ages were included in the control group. To eliminate confounding factors, all subjects were older than three years and had not used antibiotics or intestinal supplements for at least two weeks. Figure 1 illustrates the recruitment process of all subjects.
The Ethics Committee of Hunan Children’s Hospital approved this study (HCHLL-2020-53), and the parents and/or legal guardians of the enrolled children provided informed consent.
Collection of clinical and dietary data
Children’s hospitalization records were retrieved from the medical record system. The frequency, type, and duration of seizures were all considered. Further details regarding the study can be found in Changci Zhou et al. [16]. (Supplementary Table 1).
Fecal samples collection
Fecal samples were collected and kept at -80 °C within 30 min.
DNA extraction and high-throughput 16 S rDNA gene sequencing
16S rDNA amplicon sequencing was performed by Genesky Biotechnologies Inc., Shanghai, China (201315). Total genomic DNA was extracted using the FASTDNA SPIN Kit for Soil (MP Biomedicals, Santa Ana, CA) according to the manufacturer’s instructions. The integrity of the genomic DNA was assessed by agarose gel electrophoresis. The concentration and purity of the genomic DNA were measured using a Nanodrop 2000 and a Qubit 3.0 Spectrophotometer. The V4-V5 hypervariable regions of the 16S rDNA gene were amplified using the primers 515F (5’-GTGCCAGCMGCCGCGG-3) and 907R (5’-CCGTCAATTCMTTTRAGTTT-3) [17] and then sequenced on the Illumina NovaSeq 6000 platform (See Table 1).
Gut microbial analysis
QIIME2 was used to process the raw read sequences [18], while the cut adapt plugin was employed to trim adapter and primer sequences. The DADA2 plugin was used to assess quality and identify amplicon sequence variants (ASVs) [19]. A pre-trained Naive Bayes classifier, trained on the RDP (version 11.5), was applied to assign taxonomic classifications to ASV representative sequences with a confidence threshold of 0.8. To assess the sufficiency and rationality of the sample size, curve analyses, including the rarefaction curve, Shannon-Wiener curve, and species accumulation curve, were performed. Alpha-diversity was evaluated using richness (Chao1 and ACE) and diversity (Shannon and Simpson). Principal coordinates analysis (PCoA) in beta-diversity, calculated with QIIME2 and visualized using R (Version 4.1.3) was used to evaluate community composition and structure of gut microbiota. Besides, principal component analysis (PCA) based on the genus level of gut microbiota was used to evaluate the value of their contribution to epilepsy. Finally, we analyzed the microbial differences among groups at the phylum and genus levels using Metastats analysis [20] and linear discriminant analysis (LDA) effect size (LEfSe) [21].
Statistical analysis
SPSS was used to analyze the general clinical data of both the cases and controls. The Shapiro-Wilk test was applied to assess whether the data followed a normal distribution. Data are presented as the median and interquartile range [M (P25–P75)], with the Mann-Whitney U test used to compare differences between two groups and the Kruskal-Wallis test used to compare differences among multiple groups. Post-hoc multiple tests were conducted for pairwise comparisons. The Benjamini-Hochberg method was used to adjust the P-values (FDR) for multiple testing in all multiple comparison analyses [22]. A P-value of less than 0.05 was considered statistically significant.
Results
Characteristics of the study sample
There were no significant differences in age, gender, and BMI between the case group and the control group (P > 0.05, Supplementary Table 2). A comparison of clinical data between the focal epilepsy group, generalized epilepsy group, and the control group is presented in Supplementary Table 2.
Comparison with the gut microbiota among the focal epilepsy group, generalized epilepsy group, and control group
There were significant differences in alpha diversity among the focal epilepsy group, generalized epilepsy group, and control group (P<0.05, Fig. 2a-d). The ACE, Chao1, Shannon, and Simpson indices in the control group were significantly lower than those in the case group. PCoA revealed a significant divergence in the gut microbiota structure between the case and control groups (Fig. 2e). Lachnospira was the primary contributor to the variations in major components at the genus level (Fig. 2f). At the phylum level, the gut microbiota composition in the three groups was primarily dominated by Firmicutes and Bacteroidetes (Fig. 2g). The relative abundance of Bacteroidetes (P < 0.05) was significantly lower, while Firmicutes (P < 0.05) and Actinobacteria (P < 0.05) were significantly higher in the case group compared to the control group. At the genus level, the relative abundance of Bacteroides(P<0.05) was significantly lower, while Streptococcus (P<0.001) and Escherichia/Shigella (P<0.05) were significantly higher in the case group compared to the control group (Fig. 2h). LEfSe among the three groups revealed that Romboutsia and Lactobacillus were abundant in the gut microbiota of the focal epilepsy group, Ralstonia and Actinomyces were abundant in the generalized epilepsy group, and Bacteroides and Flavonifractor were abundant in the control group (Fig. 2i-j).
Comparison of the gut microbiota among the focal epilepsy group, generalized epilepsy group and the control group. (a-d) Comparison of the alpha diversity indices among three groups. (e) Principal coordinates analysis (PCoA) of beta diversity (based on the Bray–Curtis distance) based on the operational taxonomic unit (OTU) abundance table was performed to evaluate the community composition and structure of the gut microbiota. (f) Principal component analysis (PCA) based on the genus level of gut microbiota was used to evaluate the value of their contribution to epilepsy. (g-h) Metastats analysis at the phylum(g), and genus(h) levels among the three groups. (i-j) Linear discriminant analysis (LDA)(g) value distribution and the cladogram(j) of the linear discriminant analysis effect size (LEfSe)among the three groups. (LEfSe is a statistical tool used in microbiota research to identify bacterial taxa or other microbial features that are significantly different between two or more groups, and to estimate their relative effect sizes.) A: focal epilepsy group, B: generalized epilepsy group E: control group
Comparison with the gut microbiota between the focal epilepsy group and the control group
Alpha diversity in the focal epilepsy group was higher than that in the control group. (Fig. 3a-d). PCoA showed that there was a significant divergence in the gut microbiota structure between the focal epilepsy group and control groups (Fig. 3e).Megamonas was the primary contributor to the variations in major components at the genus level (Fig. 3f).According to Metastats analysis, at the phylum level, we found that the relative abundance of Bacteroidetes (0.420 vs. 0.562, P = 0.004). was significantly lower, while Firmicutes (0.511 vs. 0.401, P = 0.014) and Actinobacteria (0.015 vs. 0.003, P < 0.001) were significantly higher in the focal epilepsy group than those in the control group (Fig. 3g). At the genus level, the relative abundance of Megamonas, Streptococcus, Romboutsia, and Escherichia/Shigella was significantly higher in the focal epilepsy group than that in the control group (0.027 vs. 0.00009, P = 0.001, 0.016 vs. 0.002, P<0.001, 0.013 vs. 0.002, P = 0.001, 0.030 vs. 0.002, P<0.05, respectively) (Fig. 3h). Additionally, LEfSe also discovered Lactobacillus and Streptococcus were abundant in the focal epilepsy group. Flavonifractor and Hungatella were abundant in the control group (Fig. 3i-j).
Comparison of the gut microbiota between the focal epilepsy group and the control group. (a-d) Comparison of the alpha diversity indices between two groups. (e) Principal coordinates analysis (PCoA) of beta diversity (based on the Bray–Curtis distance) based on the operational taxonomic unit (OTU) abundance table was performed to evaluate the community composition and structure of the gut microbiota. (f) Principal component analysis (PCA) based on the genus level of gut microbiota was used to evaluate the value of their contribution to epilepsy. (g-h) Metastats analysis at the phylum(g), and genus(h) levels between the two groups. (i-j) Linear discriminant analysis (LDA)(i) value distribution and the cladogram(j) of the linear discriminant analysis effect size (LEfSe) among the two groups. (LEfSe is a statistical tool used in microbiota research to identify bacterial taxa or other microbial features that are significantly different between two or more groups, and to estimate their relative effect sizes.) A: focal epilepsy group, E: control group
Comparison with the gut microbiota between generalized epilepsy group and the control group
Alpha diversity in generalized epilepsy group was higher than that in the control group (Fig. 4a-d). PCoA showed that there was a significant divergence in the gut microbiota structure between the generalized epilepsy group and control groups (Fig. 4e). Megamonas was the primary contributor to the variations in major components at the genus level (Fig. 4f). Metastats analysis revealed that Bacteroidetes in the generalized epilepsy group, at the phylum level, decreased significantly than that in the control group (0.331 vs. 0.562, P = 0.005). Firmicutes and Actinobacteria in the generalized epilepsy group increased significantly than those in the control group (0.592 vs. 0.401, P = 0.012, 0.017 vs. 0.003, P = 0.004, respectively) (Fig. 4g). At the genus level, Escherichia/Shigella in the generalized epilepsy group was significantly higher than that in the control group (0.033 vs. 0.002, P<0.05) (Fig. 4h). LEfSe revealed that Actinomyces and Ralstonia were abundant in the generalized epileptic seizure subgroup, and Bacteroides and Faecalibacterium were abundant in the control group (Fig. 4i-j).
Comparison of the gut microbiota between the generalized epilepsy group and the control group. (a-d) Comparison of the alpha diversity indices between two groups. (e) Principal coordinates analysis (PCoA) of beta diversity (based on the Bray–Curtis distance) based on the operational taxonomic unit (OTU) abundance table was performed to evaluate the community composition and structure of the gut microbiota. (f) Principal component analysis (PCA) based on the genus level of gut microbiota was used to evaluate the value of their contribution to epilepsy. (g-h) Metastats analysis at the phylum(g), and genus(h) levels between the two groups. (i-j) Linear discriminant analysis (LDA)(i) value distribution and the cladogram(j) of the linear discriminant analysis effect size (LEfSe) among the two groups. (LEfSe is a statistical tool used in microbiota research to identify bacterial taxa or other microbial features that are significantly different between two or more groups, and to estimate their relative effect sizes.) B: generalized epilepsy group, E: control group
Comparison with the gut microbiota between the focal epilepsy group and generalized epilepsy group
There were no significant differences in alpha diversity and beta diversity between the focal epilepsy group and the generalized epilepsy group. Notably, we were unable to identify any bacteria taxa with significant differences between the focal epilepsy group and the generalized epilepsy group at the phylum and genus levels (Supplementary Fig. 2).
Comparison with the gut microbiota among the BECT group, the non-BECT group and the control group
We discovered that there were significant differences in both alpha diversity and beta diversity among the BECT group, non-BECT group and the control group (P<0.05, Fig. 5a-d). PCoA revealed a significant divergence in the gut microbiota structure among the BECT, non-BECT and control groups (Fig. 5e). Lachnospira and Megamonas were the primary contributors to the variations in major components at the genus level (Fig. 5f). Compared to the BECT and non-BECT groups, the alpha diversity in the control group was significantly lower. At the phylum and genus levels, the relative abundance of Bacteroidetes and Bacteroides (P<0.05) was more abundant in the control group than that in the other two groups. The relative abundance of Fimicutes and Actinobacteria was more abundant in the BECT group and non-BECT group (Fig. 5g-h). LEfSe also showed Collinsella and Butyricimonas were abundant in the BECT group, Lactobacillus and Ralstonia were abundant in the non-BECT group, and Flavonifractor, Hungatella and Anaerotruncus were abundant in the control group (Fig. 5i-j).
Comparison of the gut microbiota among the BECT group, non-BECTgroup and the control group. (a-d) Comparison of the alpha diversity indices among three groups. (e) Principal coordinates analysis (PCoA) of beta diversity (based on the Bray–Curtis distance) based on the operational taxonomic unit (OTU) abundance table was performed to evaluate the community composition and structure of the gut microbiota. (f) Principal component analysis (PCA) based on the genus level of gut microbiota was used to evaluate the value of their contribution to epilepsy. (g-h) Metastats analysis at the phylum(g), and genus(h) levels among the three groups. (i-j) Linear discriminant analysis (LDA)(i) value distribution and the cladogram(j) of the linear discriminant analysis effect size (LEfSe) among the three groups. (LEfSe is a statistical tool used in microbiota research to identify bacterial taxa or other microbial features that are significantly different between two or more groups, and to estimate their relative effect sizes.) C: BECT group, D: non-BECT group E: control group
Comparison with the gut microbiota between the BECT group and the non-BECT group
There were no significant differences in alpha diversity and beta diversity between the BECT and the non-BECT groups. Notably, we were unable to identify any bacteria taxa with significant differences between the BECT and the non-BECT groups at the phylum and genus levels (Supplementary Fig. 3).
Comparison with the gut microbiota between the BECT group and the control group
There was a significant difference in alpha diversity and beta diversity between the BECT group and control group (Fig. 6a-d). PCoA showed that the gut microbiota structure of the BECT group had already significantly diverged from the control group (Fig. 6e). Ruminococcus and Megamonas were the primary contributors to the variations in major components at the genus level (Fig. 6f). According to Metastats analysis, the relative abundance of Actinobacteria in the BECT group was significantly higher than that in the control group at the phylum level (0.020 vs. 0.003, P<0.001). At the genus level, the relative abundance of Megamonas and Collinsella were significantly higher in the BECT group than that in the control group (0.034 vs. 0.00009, P<0.001, 0.014 vs. 0.001, P<0.05, respectively) (Fig. 6g-h). Also, LEfSe found that Collinsella and Megamonas were abundant in the BECT group, while Faecalibacterium and Haemophilus were abundant in the control group (Fig. 6i-j).
Comparison of the gut microbiota between the BECT group and the control group. (a-d) Comparison of the alpha diversity indices between two groups. (e) Principal coordinates analysis (PCoA) of beta diversity (based on the Bray–Curtis distance) based on the operational taxonomic unit (OTU) abundance table was performed to evaluate the community composition and structure of the gut microbiota. (f) Principal component analysis (PCA) based on the genus level of gut microbiota was used to evaluate the value of their contribution to epilepsy. (g-h) Metastats analysis at the phylum(g), and genus(h) levels between the two groups. (i-j) Linear discriminant analysis (LDA)(i) value distribution and the cladogram(j) of the linear discriminant analysis effect size (LEfSe) among the two groups. (LEfSe is a statistical tool used in microbiota research to identify bacterial taxa or other microbial features that are significantly different between two or more groups, and to estimate their relative effect sizes.) C: BECT group, E: control group
Comparison with the gut microbiota between the non-BECT group and the control group
There was a significant difference in alpha diversity and beta diversity between the non-BECT group and control group (Fig. 7a-d). PCoA showed that the gut microbiota structure of the non-BECT group had already significantly diverged from the control group (Fig. 7e). Bacteroides were the primary contributor to the variations in major components at the genus level (Fig. 7f).Metastats analysis showed that, compared to the control group Bacteroidetes at the phylum level were significantly lower (0.406 vs. 0.562, P = 0.01), while Firmicutes and Actinobacteria were significantly higher in the non-BECT group (0.516 vs. 0.401, P = 0.032, 0.012 vs. 0.003, P = 0.014, respectively) (Fig. 7g). At the genus level, Megamonas, Streptococcus, Romboutsia and Escherichia/Shigella in the non-BECT group were significantly higher than those in the control group (0.023 vs. 0.00009, P = 0.013, 0.018 vs. 0.002, P<0.001, 0.014 vs. 0.002, P = 0.001, 0.037 vs. 0.002, P<0.05, respectively) (Fig. 7h). In addition, LEfSe observed that the non-BECT group’s gut microbiota was dominated by Ralstonia whereas the control group was dominated by Hungatella and Flavonifractor (Fig. 7i-j). Interestingly, the difference between Megamonas and Escherichia/Shigella was significant between both the case and control groups, as well as among the BECT group, non-BECT group, and control group, while Escherichia/Shigella did not show a significant difference between the BECT group and control group. Notably, there was a significant higher relative abundance of Escherichia/Shigella in the case group, including the non-BECT group, which may serve as a key biomarker for the prognosis and severity of epilepsy.
Comparison of the gut microbiota between the non-BECT group and the control group. (a-d) Comparison of the alpha diversity indices between two groups. (e) Principal coordinates analysis (PCoA of beta diversity (based on the Bray–Curtis distance) based on the operational taxonomic unit (OTU) abundance table was performed to evaluate the community composition and structure of the gut microbiota. (f) Principal component analysis (PCA) based on the genus level of gut microbiota was used to evaluate the value of their contribution to epilepsy. (g-h) Metastats analysis at the phylum(g), and genus(h) levels between the two groups. (i-j) Linear discriminant analysis (LDA)(i) value distribution and the cladogram(j) of the linear discriminant analysis effect size (LEfSe) among the two groups. (LEfSe is a statistical tool used in microbiota research to identify bacterial taxa or other microbial features that are significantly different between two or more groups, and to estimate their relative effect sizes.) D: non-BECT group, E: control group
Discussion
In our study, children with epilepsy exhibited statistically significant differences in gut microbiota diversity compared to healthy controls. The relative abundance of Actinobacteria, Firmicutes, Escherichia/Shigella, and Megamonas was elevated, while the relative abundance of Bacteroidetes was reduced in both the focal epilepsy group (which includes the BECT and non-BECT subgroups) and the generalized epilepsy group. Escherichia/Shigella abundance correlates with epilepsy severity, potentially making it a candidate biomarker.
Our results showed that the alpha diversity was higher not only in the focal epilepsy and the generalized epilepsy groups but also in the BECT and the non-BECT groups. We also found major differences in beta diversity between the focal epilepsy and generalized epilepsy groups and the control group, as well as between the BECT and non-BECT groups compared to the control group. The principal components analysis found that Megamonas was primarily responsible for the genus-level variations in between the BECT and non-BECT groups and the control group. Peng and colleagues found that, based on alpha diversity analysis, the gut microbiota abundance in drug-resistant epilepsy patients was higher than that in drug-sensitive epilepsy patients and healthy individuals [23]. Carlson and colleagues revealed that the diversity of gut microbiota was associated with cognitive function, as the higher the alpha diversity was, the worse cognitive performance would be [21]. At the same time, A relationship was found between gut microbiota diversity and cognitive function, with higher alpha diversity being associated with poorer cognitive performance [16]. Therefore, we assumed that the microbial communities in children with focal epilepsy were more diverse and distinct from those in healthy children.
Our study showed that the gut microbiota in all three groups was predominantly composed of Bacteroidetes and Firmicutes at the phylum level. When compared to the control group, the relative abundance of Actinobacteria and Firmicutes was increased, while the relative abundance of Bacteroidetes was decreased in the focal epilepsy group (including the BECT group, the non-BECT group) and the generalized epilepsy group at the phylum level. Previous research has demonstrated that this composition is characteristic of a healthy gut microbiota. After 12 months, Bacteroidetes and Firmicutes dominate in both children and adults, which aligns with our findings that the gut microbiota of healthy children and those with focal epilepsy are similar in composition [24], with variations in abundance. The study found that Bifidobacterium fragilis improves epilepsy symptoms by modulating the immune system, reducing inflammation, and affecting the release of neurotransmitters [25].
Additionally, at the genus level, Escherichia/Shigella were significantly more abundant in patients with poor prognosis (such as those in the focal epilepsy group, generalized epilepsy group, and non-BECT group), whereas no significant differences were observed in the BECT and control groups. Studies have shown that Escherichia/Shigella induces pro-inflammatory cytokines through NLRP3 inflammasome-dependent mechanisms [26, 27]. In addition, previous research found a correlation between the levels of IL-1beta, CXCL2, and NLRP3 inflammasomes and the amount of pro-inflammatory Escherichia/Shigella in stool, with higher levels observed in patients with cognitive impairment and Alzheimer’s amyloidosis compared to the controls [28]. Inflammasomes have been extensively studied to understand how they contribute to the onset of neurological disorders, such as Alzheimer’s disease, multiple sclerosis, stroke, and traumatic brain injury [29]. Melatonin may reduce the frequency of epilepsy and seizures [30, 31]. Melatonin has been shown to decrease the occurrence of seizures and epilepsy [32]. Jia’s team also observed that after creating an epileptic mouse model and treating it with melatonin, NLRP3, caspase-1, and IL-1β were significantly elevated in untreated epileptic mice compared to the treatment and control groups [33]. These findings suggested that Escherichia/Shigella may contribute to the development and progression of epilepsy through inflammatory mechanisms. Previous studies have shown that the abundance of Escherichia/Shigella significantly differs before and after treatment [16], suggesting that as the condition improves, the abundance of potential pathogens may decrease accordingly. Therefore, we could conclude that the increase of Escherichia/Shigella may play a role in contributing to poor prognosis and the progression of clinical phenotypes, and it could be a candidate biomarker to identify the focal epilepsy or even non-benign childhood epilepsy with centrotemporal spikes.
We also found that focal epilepsy could be associated with changes in the relative abundance of certain other genera, such as an increase in Streptococcus, Collinsella, Megamonas, and Romboutsia.
Our results further confirmed that Streptococcus was historically more prevalent in both the focal and generalized epilepsy groups. Some studies suggest that the enrichment of Streptococcus may elevate the levels of IL-6 and TNF-α [34], which could, in turn, induce epilepsy in children with focal epilepsy by triggering neuroinflammation. This is because IL-6 is linked to epileptic seizures, while TNF-α can increase nervous system excitability by enhancing Ca2 + influx [35, 36].
In addition, the Megamonas [37] level in the focal epilepsy group was significantly higher than that in the control group. One study found a significant increase in Megamonas in children with autism spectrum disorder [38]. The article about the correlation between infantile spasms and gut microbiota found that, two weeks after treatment for infantile spasms, the Megamonas level that in the ineffective group was higher than in the effective treatment group, which was consistent with our article [39].
Interestingly, the Collinsella level in the BECT group was significantly higher than that of the control group. Collinsella produces short-chain fatty acids (SCFAs). SCFAs can modulate inflammation and reduce the number of inflammatory macrophages and Th 17 cells in the gut, and were once considered important signaling molecules in gut microbiota-brain communication [37, 40]. Previous studies have shown that an enrichment of Collinsella might reduce the growth of fermenting bacteria that produce SCFAs [41, 42]. Collinsella may potentially promote intestinal permeability by decreasing tight junction protein expression in epithelial cells and increasing IL-17 production. IL-17α is an critical cytokine that can improve macrophages, endothelial cells to produce a large number of inflammatory factors, and promote the occurrence and development of neurological diseases [43]. Related studies have found that IL-17α was higher in cerebrospinal fluid in children with acute seizures [44]. The study on the correlation between infantile spasms and gut microbiota confirmed that the IL-17α levels in infants with spasms were higher than those in the healthy group, and that IL-17α levels decreased after treatment and improvement of the condition [39]. In addition, studies have shown that inter-seizure IL-17α levels have been strongly linked to seizure frequency and severity [45, 46]. Therefore, we could hypothesize that Collinsella and Megamonas could affect the activation of inflammatory cells by affecting the production of short-chain fatty acids, thus causing changes in intestinal permeability, increase inflammatory factors (IL-17α) into the blood, and finally lead to changes in brain tissue and cells, and promote the progression of epilepsy. We will then test the above hypothesis through animal and cell experiments.
The role of Romboutsia in the pathogenesis of epilepsy remains unclear. IN the current study, we found that the severity of the Dravet mouse phenotype, as well as the concentrations of GABA/Glutamate-glutamine cycle factors and glucose levels in hippocampal tissue, were all associated with lower levels of the Romboutsia genus [47]. Given the knowledge gap regarding Romboutsia as a short-chain fatty acid-producing bacterium and its role in epilepsy, it may be interesting to further investigate its potential as a disease marker in Dravet syndrome and other epilepsies [47].
There were no significant differences in alpha diversity and gut microbiota between the focal epilepsy and generalized epilepsy groups, which was also the case between the BECT and non-BECT groups. Current studies have not yet identified differences in gut flora among different types of epilepsy, possibly due to limitations in the current level of scientific research. We look forward to further studies in the future.
In summary, the gut-brain axis plays a crucial role in the onset and severity of epilepsy. A combination of probiotics (Lactobacillus rhamnosus, Lactobacillus reuteri, and Bifidobacterium infantis) [48], as well as Lactobacillus species (casei, acidophilus) and Bifidobacterium bifidum [49], has shown beneficial effects in an animal model of epilepsy, specifically the pentylenetetrazole-induced kindling model. The researchers found that the levels of Lactobacillus, Roseburia, and Lachnospira were lower in the infantile spasms group (a type of epilepsy) compared to the healthy group. Additionally, the study revealed that the ratio of Bacteroidota to Firmicutes was higher in epilepsy rats compared to non-epileptic rats. Research has demonstrated that probiotic supplements can significantly reduce both the onset and severity of epilepsy. Specific gut microbiota may serve as a potential therapeutic target for epilepsy in the future, with disease control achievable through the restoration of gut microbiota [50].
Our study also has certain limitations. Firstly, it was a single-center study with a limited sample size, and we used associative approaches rather than causal or experimental methods, which made it difficult to determine the causal relationship between gut microbiota and focal epilepsy. Due to the small number of patients included in this study, it was not possible to perform a statistically robust analysis of confounding factors using multivariate models. However, according to the species accumulation curve of the sample (Supplementary Fig. 1), a total of 51 samples participated in the analysis in this study, and the sample size was sufficient, which could fully reflect the richness of the microbiota. Secondly, the case and control groups were from different families, and we did not control the effects of dietary and regional differences on intestinal flora. Thirdly, the metabolites of the intestinal flora were not measured, so the potential mechanisms between gut microbiota and epilepsy could not be thoroughly analyzed. Finally, children with epilepsy were not followed up for treatment outcomes. However, for the first time, 16 S rDNA high-throughput sequencing and analysis of the gut microbiota in children with focal epilepsy and generalized epilepsy revealed the characteristics and differences in the gut microbiota between these two groups, providing a basis for further research into the potential role of differential gut microbiota distribution in the pathogenesis of epilepsy. This also suggests approaches like fecal microbiota transplantation for the treatment of pediatric epilepsy and offers direction for future research on bacterial metabolites in epilepsy. Although the exact mechanism underlying the amplification of Escherichia/Shigella in the gut microbiota of epilepsy patients remains unclear, our findings provide important insights for improving the clinical management of epilepsy. In the future, there can be more collaboration among multiple centers to increase the sample size. We did not fully explore the potential impact of diet on the gut microbiota in this study, which could be a confounding factor in our findings.
Conclusions
The gut microbiota of children with epilepsy differs from that of healthy children. In children with epilepsy, the abundance of Megamonas and Escherichia/Shigella is increased. Specifically, the abundance of Escherichia/Shigella is significantly higher in the poor prognosis groups. This suggests that the increased abundance of Escherichia/Shigella may lead to poor prognosis and the worsening of clinical phenotypes, and it could be a candidate biomarker to identify the focal epilepsy or even non-benign childhood epilepsy with centrotemporal spikes, potentially providing new therapeutic targets for the future.
Data availability
No datasets were generated or analysed during the current study.
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Acknowledgements
We would like to thank all the children and parents who participated in this study, and we appreciate the support from the data collectors. All authors had access to the study data and reviewed and approved the final manuscript.
Funding
Opening fundings of Hunan Provincial Key Laboratory of Pediatric Orthopedics(2023TP1019), Science and Technology Project of Furong Laboratory(2023SK2111), Hunan Provincial Clinical Medical Research Center for pediatric Limb Deformities. This research was funded by the Science and Technology Department of Hunan Province (2017SK2154).
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SWF, NFH and JQ contributed to the conception and design of the study. Administrative support was provided by LWW, ZHX and JQ. LWW provided the study materials. NFH collected and assembled the data which underwent statistical analysis and interpretation by SWF, JJY, CCZ and JQ.All authors read and approved the final version of manuscript.
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The Ethics Committee of Hunan Children’s Hospital approved this study (HCHLL-2020-53), and informed consent was obtained from the parents and/or legal guardians of the enrolled children.
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Fang, S., Hu, N., Zhou, C. et al. The comparison of gut microbiota between different types of epilepsy in children. Microb Cell Fact 24, 64 (2025). https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12934-025-02684-2
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DOI: https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12934-025-02684-2