Gastrointestinal Microflora Studies in Late‐Onset Autism

TLDR

Late‑onset autism may involve abnormal gut flora, as oral vancomycin, a poorly absorbed antibiotic, has shown significant improvement in some children. The study compared fecal flora of children with regressive autism to controls, finding higher clostridial counts in the autistic group. Autistic children exhibited a greater diversity of clostridial species—nine unique to them versus three unique to controls—with a total of 25 species, and significant differences in upper and lower intestinal flora, including the absence of non‑spore‑forming anaerobes in controls and their presence in autistic children.

Abstract

Some cases of late-onset (regressive) autism may involve abnormal flora because oral vancomycin, which is poorly absorbed, may lead to significant improvement in these children. Fecal flora of children with regressive autism was compared with that of control children, and clostridial counts were higher. The number of clostridial species found in the stools of children with autism was greater than in the stools of control children. Children with autism had 9 species of Clostridium not found in controls, whereas controls yielded only 3 species not found in children with autism. In all, there were 25 different clostridial species found. In gastric and duodenal specimens, the most striking finding was total absence of non—spore-forming anaerobes and microaerophilic bacteria from control children and significant numbers of such bacteria from children with autism. These studies demonstrate significant alterations in the upper and lower intestinal flora of children with late-onset autism and may provide insights into the nature of this disorder.