New research has found that a little known genus of bacteria named Sutterella may play a significant role in the symptomology of cases of autism that also involve digestive disturbances.
Gastrointestinal disturbances are commonly reported in children with autism and may be associated with changes in the composition of the intestinal bacteria. The role of the gut microbiota is increasingly being recognised by scientists as playing an important role in health and disease.
Researchers from the Center for Infection and Immunity, Columbia University, New York, had proposed that unusual composition of intestinal bacteria was associated with autism with gastrointestinal involvement (AUT-GI). They had previously demonstrated that some AUT-GI children were carrying bacteria from the family Alcaligenaceae in their guts, while the same was not the case for children in a control group who had gastrointestinal complaints but not autism (Control-GI).
In the current study the team enrolled 23 AUT-GI and 9 Control-GI children and examined ileal and caecal biopsy samples from each.
They used polymerase chain reaction (PCR) techniques to detect and categorise microbial DNA to form a picture of the gut microbiota of each child.
Sutterella gene sequences were found in 12 of 23 AUT-GI children but in none of 9 Control-GI children. Specifically, analysis revealed a predominance of either Sutterella wadsworthensis or Sutterella stercoricanis in 11 of the individual Sutterella-positive AUT-GI patients. In the remaining Sutterella-positive child the exact species could not be identified. Sutterella belongs to the Alcaligenaceae family of bacteria previously identified.
Following the PCR analysis the investigators used Western blot assays to look for an immune response to Sutterella in the AUT-GI children. This work revealed plasma IgG or IgM antibody reactivity to Sutterella wadsworthensis antigens in 11 AUT-GI patients, 8 of whom were also PCR positive, indicating the presence of an immune response to Sutterella in some children.
The researchers assert that gastrointestinal disturbances can complicate clinical management and contribute to behavioural problems in children with autism so understanding the role of gut microbes is of upmost importance. A greater understanding of the microbes involved would, they say, benefit both diagnosis and informed treatment, leading to better outcomes for AUT-GI children.
Source: Williams BL Hornig M Parekh T Lipkin WI (2012) Application of Novel PCR-Based Methods for Detection, Quantitation, and Phylogenetic Characterization of Sutterella Species in Intestinal Biopsy Samples from Children with Autism and Gastrointestinal Disturbances mBio 3(1): e00261-11