Communities of microorganisms that reside in the gut of
autistic children with gastrointestinal problems are different than communities
residing in non-autistic children, according to study results published in the
online journal mBio.
Following up on a previous study, which identified that
Alcaligenaceae bacterium sequences in ileal and cecal biopsy samples
autistic children with gastrointestinal dysfunction were
completely absent from biopsy samples of non-autistic children with
gastrointestinal dysfunction, Brent Williams, PhD, and colleagues of the
Mailman School of Public Health at Columbia University subjected samples to
real-time polymerase chain reaction (PCR) analysis.
Researchers analyzed 23 biopsy samples from autistic
children with nine biopsy samples from non-autistic children and observed that
increased levels of Alcaligenaceae in autistic children resulted from
the incidence of elevated levels of members of the genus Sutterella.
Utilizing a Sutterella-specific PCR assay for detecting, quantitating
and genotyping Sutterella species in the samples, the study found
Sutterella 16S ribosomal RNA (rRNA) gene sequences in 12 of 23 autistic
children, yet none in the nine non-autistic children.
Further phylogenetic analysis identified a high
proportion of either S. wadsworthensis or S. stercoricanis in 11
of the Sutterella-positive autistic patients, whereas the remaining
patient could not be given a species-level classification based on the 16S rRNA
gene sequences of known Sutterella isolates.
“The nature of
intestinal damage in autism has not been fully defined,”
the researchers said. “A defective epithelial barrier could lead to
enhanced contact between many members of the microbiota and antigen-presenting
cells in the lamina propria. If this turns out to be the case in autism, then
antibodies against Sutterella proteins may reflect interindividual,
compositional variation in the microbiota, rather than being an indication of
Sutterella infection. Additional studies are warranted in order to draw
definitive conclusions from this immunological analysis.”
Disclosure: The researchers report no relevant