I was acutely involved in similar work a while ago (I was a donor for many C diff, IBS, Crohns patients and autism patients). The science/theory may have chang

I was acutely involved in similar work a while ago (I was a donor for many C diff, IBS, Crohns patients and autism patients). The science/theory may have changed, but the potential link between gut microbiome and autism for awhile was thought to do with the levels of Clostrium (Clostridia?... can't remember back to my microbiology days) bacteria in babies. Most babies are born with high levels of Clostridium species in their gut, as you may know, clostridium are usually very good at producing toxins (botulism, c. diff, perfringens etc). Majority of babies seem to get rid of these bacteria at 10 months or so, but those with autism seem to hold onto them. The thinking is these bacteria continue to produce low levels of neurotoxins that affect the brain. It seems to be supported with anecdotal research which shows improvement in autism symptoms in younger children who are given transplants but not older children. The thought being the years of toxin affect on the brain has been too much.