Bacteria belonging to the group Sutterella represented a relatively large proportion of the microorganisms found in 12 of 23 tissue samples from the guts of autistic children, but these organisms were not detected in any samples from non-autistic children. Why this organism is present only in autistic kids with gastrointestinal problems and not in unaffected kids is unclear.
"Sutterella has been associated with gastrointestinal diseases below the diaphragm, and whether it's a pathogen or not is still not clear ..."
.... Benach says the study was uniquely powerful because they used tissue samples from the guts of patients. "Most work that has been done linking the gut microbiome with autism has been done with stool samples," says Benach, but the microorganisms shed in stool don't necessarily represent the microbes that line the intestinal wall. "What may show up in a stool sample may be different from what is directly attached to the tissue," he says.