Microbiome analysis of circulating bacterial extracellular vesicles in obsessive-compulsive disorder.

Abstract

The present study examined the microbiome abundance and composition of drug-naïve or drug-free patients with obsessive-compulsive disorder (OCD) compared to healthy controls. In addition, in the OCD group, the microbiome composition was compared between early-onset and late-onset OCD. Serum samples were collected from 89 patients with OCD and 107 age- and sex-matched healthy controls. Bacterial DNA was isolated from bacteria-derived extracellular vesicles in serum and then amplified and quantified using primers specific to the V3-V4 hypervariable region of the 16S rDNA gene. The 16S rRNA gene amplicon sequencing was performed. The pooled estimate showed that alpha diversity was significantly reduced in patients with OCD compared to that in healthy controls (pShannon = 0.00015). In addition, a statistically significant difference was observed in beta diversity between patients with OCD and healthy controls at the order (p = 0.012), family (p = 0.003), genus (p < 0.001), and species (p = 0.005) levels. In the microbiome composition, Pseudomonas, Caulobacteraceae(f), Streptococcus, Novosphingobium, and Enhydrobacter at the genus level were significantly less prevalent in patients with OCD than in controls. In addition, among patients with OCD, the microbial composition in the early-onset versus late-onset types was significantly different with respect to the genera Corynebacterium and Pelomonas. The present study showed an aberrant microbiome in patients with OCD, suggesting a role of the microbiota-brain interaction in the pathophysiology of OCD. Further longitudinal studies with larger sample sizes adjusting for various confounders are warranted. This article is protected by copyright. All rights reserved.