Gut Microbiota Characteristics and the Efficacy of Fecal Microbiota Transplantation in Children with Autism Spectrum Disorder in Central China: A Cross-sectional and Prospective Combined Study

This study aims to investigate the gut dysbiosis profiles in children with autism spectrum disorder (ASD) and to explore the clinical efficacy of a simplified fecal microbiota transplantation (FMT) protocol, as well as its microbial remodeling mechanisms. Firstly, a cross-sectional cohort study analyzed the intestinal microbiota of 48 children with ASD and 51 healthy controls (HC). The results indicated that the ASD group exhibited reduced gut microbial diversity, characterized by decreased abundances of Faecalibacterium and Bifidobacterium, along with an enrichment of Megamonas and Akkermansia. Subsequently, young donors were recruited and a simplified FMT protocol was administered to 25 children with ASD, comprising three-day bowel preparation followed by six-day colonoscopic infusion. A three-month follow-up revealed significant improvements in both core and gastrointestinal symptoms. Microbiota analysis confirmed that FMT effectively reshaped the microbial structure: the primary changes included an increase in the relative abundances of the genera Prevotella, Faecalibacterium, Agathobacter, and Dorea, along with a decrease in Escherichia-Shigella. The observed reduction in the abundance of Bifidobacterium following FMT was explained through the colonization competition theory of "distant friendship and nearby attack. This protocol establishes a safe and effective practical paradigm for FMT in pediatric patients with ASD.