Analysis of gut mycobiota in first-episode, drug-naive Chinese patients with schizophrenia: A pilot study

Background: Accumulating evidence has focused on elucidating the bacterial component of the gut microbiota in patients with schizophrenia (SC); however, the fungal composition in the gut has not been investigated, although previous studies have suggested that gut mycobiota may be intricately linked to this disorder. The purpose of this analysis was to examine gut bacterial and fungi in first-episode, drug-naive adult SC patients in relation to age- and sex-matched healthy controls (HC). Methods: Ten SC patients and 16 HCs were enrolled in this cross-sectional study, and their gut microbiota and mycobiota were systematically characterized using 16S rRNA gene- and ITS1-based DNA sequencing. Results: The microbiota of the SC patients were characterized by increased abundance of harmful bacterial (Proteobacteria) and decreased short-chain fatty acid (SCFA)-producing bacteria, such as the Faecalibacterium and Lachnospiraceae genera. The gut mycobiota were characterized by a relative reduction in alpha diversity and altered composition. Most notably, the SC group had a higher level of Chaetomium and a lower level of Trichoderma than the HC group. Furthermore, the gut microbiota in patients with SC displayed a significant enhancement in the bacteria-fungi correlation network, suggestive of altered interkingdom interactions. Conclusions: Both the bacterial gut microbiota as well as the gut mycobiota contributed to gut dysbiosis in patients with SC. However, our study was limited by sample size, and additional studies involving larger cohorts characterizing the gut mycobiome in SC patients are needed to form a foundation for research into the relationship between mycobiota, dysbiosis, and SC development.