Autism: a new fecal microbiota transplant protocol shows promising results

In autistic children, an intensive combined protocol based on fecal microbiota transplant showed long-term significant reduction in disease-associated gastrointestinal and behavioral disorders. These encouraging results still have to be confirmed.

Created 25 June 2019
Updated 06 October 2021

About this article

Created 25 June 2019
Updated 06 October 2021


Gut dysbiosis and gastrointestinal disorders are frequently observed in children with autism spectrum disorders (ASD). That is why, American researchers had previously tested a treatment protocol based on fecal microbiota transplant (FMT) in 18 autistic children aged 7 to 17 years. In a new study, they reported changes in the participants’ symptoms two years after that first study.

Intensive protocol, durable results

The protocol, called “Microbial Transfer Therapy” (MTT), included a 2-week vancomycin treatment course, an enema, two days of FMT, followed by 7 to 8 weeks of FMT combined with gastric acid suppression with omeprazole. After this initial 18-week trial, gastrointestinal symptoms improved by 80% and autistic symptoms slightly decreased (communication difficulties, repetitive behaviors...). These positive results were maintained two years later: gastrointestinal disorders were 58% lower compared to the beginning of the study. Disease severity was measured by a professional and it sharply decreased: 83% of the children were considered as “severely autistic” at the beginning of the study, while two years later, 17% were rated as severe, 39% were in the mild to moderate range, and 44% of participants were below the ASD diagnostic cut-off scores.

Implantation of a healthier microbiota

Stool analysis of 16 out of the 18 participants also showed that, in most children, bacterial diversity was higher after two years than at the end of the 18 weeks of the initial trial, thus showing that the protocol had created a healthier microbial environment, favorable to the improvement of gastrointestinal and behavioral symptoms. More precisely, relative abundances of Bifidobacteria and Prevotella were multiplied by 5 and 84, respectively. This was a significant finding, since Prevotella (frequently depleted in autistic patients) is a bacterial genus that produces butyrate, a short-chain fatty acid favorable to gut mucosa. However, a cautious approach should be adopted here: the researchers indicated that during the two-year follow-up period, 12 out of the 18 children underwent changes in medication, diet or dietary supplements and that the omeprazole effect might explain by itself the improvement of symptoms related to gastric acidity. A randomized double-blind trial with a larger cohort is necessary to validate the hopes resting on this new protocol.


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