Profiles of amino acids and gaseous signaling molecules produced by intestinal staphylococci and lactobacilli isolated from healthy individuals and patients with autism spectrum disorder

Relevance. In recent years, researchers have increasingly focused on the metabolic activity of the gut microbiota as a potential factor in the development of various diseases. The rising prevalence of autism spectrum disorder (ASD) has intensified efforts to identify additional etiological factors and develop new therapeutic approaches. Numerous studies suggest that the disturbances in amino acid metabolism and in the metabolism of gaseous signaling molecules involved in nervous system regulation observed in these patients may be partly attributable to bacterial activity.

Objective. To characterize the profiles and concentrations of amino acids and gaseous signaling molecules produced by intestinal staphylococcal and lactobacillus strains isolated from healthy children and children with ASD.

Materials and methods. Fecal samples from 12 healthy children and 12 children with ASD were analyzed using conventional bacteriological methods. Amino acid production by the bacterial isolates was assessed by high-performance liquid chromatography coupled with mass spectrometric detection, and gaseous signaling molecule production was measured by gas chromatography.

Results. Compared with strains isolated from healthy children, intestinal bacterial strains from children with ASD produced higher levels of glutamate and lower levels of leucine, isoleucine, and lysine, in line with the limited evidence reported in the literature. In addition, Staphylococcus aureus strains isolated from children with ASD produced less threonine and phenylalanine but more proline. Lactobacillus rhamnosus strains isolated from children with ASD produced greater amounts of both NO and CO than strains isolated from healthy children.

Conclusion. The gut microbiota of children with ASD differs from that of healthy children in its amino acid and gaseous signaling molecule metabolism. Further studies are needed to determine whether microbial metabolites contribute to the development of neurological disorders. These findings should be used to expand the range of diagnostic and therapeutic tools available to neurologists treating children with ASD.

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