New research conducted in the Center for Infection and Immunity (CII) at Columbia University's Mailman School of Public Health, reports that children with autism and gastrointestinal disturbances have high levels of a bacterium called Sutterella in their intestines.
Study findings are published online in the journal mBio.
The investigators found that over half of the children diagnosed with autism and gastrointestinal disturbances had Sutterella in intestinal biopsy tissue, while Sutterella was absent in biopsies from typically developing children with gastrointestinal disturbances. Not only was Sutterella present in the intestines of children with autism, but relative to most genera of bacteria, Sutterella was present at remarkably high levels. Sutterella species have been isolated from human infections previous to this study, but it remains unclear whether this bacterium is a human pathogen.
"These findings shine a light on a bacterium about which we know very little, in a disorder for which we have few answers," says Brent Williams, PhD, the lead author on the study. "There is much work to be done toward understanding the role Sutterella plays in autism, the microbiota, infections, and inflammation."
The researchers examined intestinal biopsies from 32 patients, 23 diagnosed with autism and 9 typically developing children. While previous studies investigating a link between the microbiota and autism have utilized stool samples, the study was unique in investigating bacteria adherent to the intestinal wall, which may be different than what is shed in the stool. Furthermore, the researchers designed and applied novel Sutterella-specific molecular assays to enable detection, quantitation, and phylogenetic analysis of Sutterella species in biological and environmental samples.
Many children with autism have gastrointestinal problems that can complicate clinical management and contribute to behavioral disturbances. However, the underlying reason that autism is associated with gastrointestinal disturbances is unknown.
"Although caution in interpretation is indicated because this is a small cohort, microbiome research may provide new insights into gastrointestinal disturbances that develop in children with autism," notes Mady Hornig, MD, Mailman School associate professor and director of Translational Research at the CII.