The gut microbiome offers some new potential for some Autism Spectrum Disorders (ASD). While the research is not yet conclusive, there appears to be a number of indicators that within the spectrum of these disorders are some that may have a microbial link.
The challenge is that ASD covers many different diseases. It has many different versions which could involve many different microbes (or no microbes at all) and different eating habits that affect the gut microbiome.
There are some smoking guns that suggest there is a connection for some forms of autism. There appear to be some reports of kids taking antibiotics and developing autism and there is some research into fecal transfer that seem to be a way to decrease autism.
We are far from discovering exactly what microbes could help, but as more research and larger clinical human trials are completed there is some hope for the future.