Efficacy and safety of microbiota transfer therapy for the management of autism spectrum disorder in children: a systematic review

Background: Autism spectrum disorder (ASD) is a neurodevelopmental condition associated with an unclear etiologic mechanism. Following suggestions in the literature of a close relation between the gut microbiota and the central nervous system development, neuroimmune and neuroendocrine systems, new theories and strategies of the management of ASD in children focus on the brain-gut axis via microbiota transfer therapy. Despite the regular appearance in the news, the level of evidence supporting this intervention is unclear and to this date, no systematic review on this issue has been published. Methods: We conducted a systematic literature review of the efficacy and safety of microbiota transfer therapy for the management of ASD in children. MEDLINE via PubMed, LILACS IBECS via BVS, EMBASE via Ovid, Scopus and Cochrane Library were searched on 19th April 2018. Results: One single study published in 2017 was identified. The intervention group included 18 patients and showed significant clinical improvements in the gastrointestinal and ASD-related symptoms. The clinical procedure was reported as safe and well-tolerated with some transitory adverse effects. Conclusions: The causality and correlation of the intervention and the expected outcomes cannot be assumed with current evidence. In addition, recommendations about the effectiveness or safety of microbiota transfer therapy in children with ASD cannot be currently issued. Randomized controlled trials and clinical protocols for the intervention are needed.