biostudies-literatureLee EHNational Research Foundation of Korea2149020https://www.ebi.ac.uk/biostudies/studies/S-EPMC9728469biostudies-literatureUnknown14(1)Rheumatoid arthritis (RA) is closely associated with the oral and gut microbiomes. Fungal cell wall components initiate inflammatory arthritis in mouse models. However, little is known regarding the role of the fungal community in the pathogenesis of RA. To evaluate the association between RA and the gut microbiome, investigations of bacterial and fungal communities in patients with RA are necessary. Therefore, we investigated the compositions and associations of fecal bacterial and fungal communities in 30 healthy controls and 99 patients with RA. The relative abundances of <i>Bifidobacterium</i> and <i>Blautia</i> decreased, whereas the relative abundance of <i>Streptococcus</i> increased, in patients with RA. The relative abundance of <i>Candida</i> in the fecal fungal community was higher in patients with RA than in healthy controls, while the relative abundance of <i>Aspergillus</i> was higher in healthy controls than in patients with RA. <i>Candida</i> species-specific gene amplification showed that <i>C. albicans</i> was the most abundant species of <i>Candida</i>. Ordination analysis and random forest classification models supported the findings of structural changes in bacterial and fungal communities. <i>Aspergillus</i> was the core fecal fungal genus in healthy controls, although <i>Saccharomyces</i> spp. are typically predominant in Western cohorts. In addition, bacterial-fungal association analyses showed that the hub node had shifted from fungi to bacteria in patients with RA. The finding of fungal dysbiosis in patients with RA suggests that fungi play critical roles in the fecal microbial communities and pathogenesis of RA.Gut microbesDysbiotic but nonpathogenic shift in the fecal mycobiota of patients with rheumatoid arthritis.PMC9728469NRF-2016M3A9D391585722Kim HPan CHLee EHLee KKKim WUCha KHKoh JHLee YHfalseDysbiotic but nonpathogenic shift in the fecal mycobiota of patients with rheumatoid arthritis.Rheumatoid arthritis (RA) is closely associated with the oral and gut microbiomes. Fungal cell wall components initiate inflammatory arthritis in mouse models. However, little is known regarding the role of the fungal community in the pathogenesis of RA. To evaluate the association between RA and the gut microbiome, investigations of bacterial and fungal communities in patients with RA are necessary. Therefore, we investigated the compositions and associations of fecal bacterial and fungal communities in 30 healthy controls and 99 patients with RA. The relative abundances of <i>Bifidobacterium</i> and <i>Blautia</i> decreased, whereas the relative abundance of <i>Streptococcus</i> increased, in patients with RA. The relative abundance of <i>Candida</i> in the fecal fungal community was higher in patients with RA than in healthy controls, while the relative abundance of <i>Aspergillus</i> was higher in healthy controls than in patients with RA. <i>Candida</i> species-specific gene amplification showed that <i>C. albicans</i> was the most abundant species of <i>Candida</i>. Ordination analysis and random forest classification models supported the findings of structural changes in bacterial and fungal communities. <i>Aspergillus</i> was the core fecal fungal genus in healthy controls, although <i>Saccharomyces</i> spp. are typically predominant in Western cohorts. In addition, bacterial-fungal association analyses showed that the hub node had shifted from fungi to bacteria in patients with RA. The finding of fungal dysbiosis in patients with RA suggests that fungi play critical roles in the fecal microbial communities and pathogenesis of RA.2022-01-01T00:00:00Z2022 Jan-Dec2025-04-19T05:10:01.394Z2025-04-19T05:10:01.394ZS-EPMC97284693647246810.1080/19490976.2022.2149020