Gut Microbiota Composition in Helicobacter pylori-Positive Adolescents With Autism Spectrum Disorder: An Exploratory Compositional Analysis.

Alterations in the gut microbiota have been implicated in autism spectrum disorder (ASD), but reported microbial profiles remain inconsistent, potentially because of heterogeneity in factors affecting gut microbial composition. Because Helicobacter pylori infection is associated with alterations in the gut microbiota, we investigated whether ASD was associated with gut microbial composition in a cohort of H. pylori-positive adolescents. This cross-sectional study included seven adolescents with ASD and 80 controls before H. pylori eradication therapy. Gut microbiota was analyzed using 16S rRNA gene sequencing, with alpha diversity, centered log-ratio-transformed genus-level abundance, and overall community composition based on Aitchison distance evaluated between groups. No significant differences were observed in alpha diversity or overall microbial community composition. At the genus level, 82 genera met the prevalence criterion for individual testing, and no association remained significant after false-discovery-rate correction. The effect estimate for Roseburia was not statistically significant in either unadjusted or adjusted analyses. These findings do not support marked differences in overall gut microbiota composition associated with ASD within this H. pylori-positive cohort; however, the small ASD sample and substantial age imbalance limit the precision and interpretation of the findings.