Fecal Fungal Community Structure of Newly Diagnosed Patients With Crohn's Disease in Suzhou, Jiangsu Province / 胃肠病学

ABSTRACT

Background: The pathogenic mechanism of Crohn's disease (CD) is currently unclear. Previous studies have shown that intestinal microorganism plays an important role in the pathogenesis of CD. Aims: To study the fecal fungal community structure of CD patients in Suzhou, Jiangsu Province and to analyze the relationship between alterations in fugal community structure and disease status. Methods: The feces of 23 newly diagnosed CD patients and 18 healthy subjects in Suzhou, Jiangsu Province were collected. Fecal genomic DNA was extracted, and the ITS1 fragments were amplified by PCR for clone library construction. After sequencing on HiSeq platform, the species diversity of fecal samples and the species differences between different groups were analyzed based on OTUs. Furthermore, the correlations between the fungi with up-regulated abundance and inflammatory indicators (CRP, ESR, and fecal calprotectin) and CD activity index (CDAI) were analyzed. Results: The fungal species diversity in fecal samples was significantly reduced in CD patients compared with healthy subjects. From the levels of phylum, class, order, family, genus, and species, the fungi with up-regulated abundance in fecal samples of CD patients were Saccharomycetes, Saccharomycetales, Incertae_sedis, Candida and Candida albicans; the fungi newly emerged were Trichosporonales and Trichosporonaceae; Wallemiomycetes was down-regulated in abundance and Glomeromycota, Glomeromycetes, Glomeraceae, Lodderomyces, Candida intermedia, and Candida sp were absent. The abundance of Candida albicans in feces was positively correlated with the fecal calprotectin in CD patients (r=0.557, P=0.031). Conclusions: Compared with healthy subjects, the structure of intestinal fungal community in CD patients changed significantly. The species diversity was reduced and the abundance of opportunistic pathogenic fungi such as Candida albicans was increased and might be involved in the disease progression.