苏州地区初发克罗恩病患者粪便真菌菌群结构研究

Fecal Fungal Community Structure of Newly Diagnosed Patients With Crohn’s Disease in Suzhou,Jiangsu Province

背景:克罗恩病(CD)的发病机制目前尚不明确,研究表明肠道微生物在其中起重要作用。目的:研究苏州地区CD患者粪便真菌菌群结构变化及其与疾病间的关联。方法:纳入苏州地区初发CD患者23例和健康对照者18例,采集粪便样本提取基因组DNA,PCR扩增ITS1片段构建克隆文库,HiSeq平台测序,基于OTU行样本物种多样性分析和组间物种差异分析,并进一步分析在CD患者中丰度上调的真菌与炎性指标CRP、ESR、粪便钙卫蛋白和CD活动指数(CDAI)的相关性。结果:CD患者粪便样本中的真菌物种多样性显著小于健康人。从门、纲、目、科、属、种各水平分析,CD患者粪便中丰度显著上调的真菌为酵母纲(Saccharomycetes)、酵母目(Saccharomycetales)、位置未定科(Incertae_sedis)、念珠菌属(Candida)、白念珠菌(Candida albicans),新增真菌为丝孢酵母目(Trichosporonales)、丝孢酵母科(Trichosporonaceae),丰度显著下调的真菌为节担菌纲(Wallemiomycetes),缺失真菌为球囊菌门(Glomeromycota)、球囊菌纲(Glomeromycetes)、球囊霉科(Glomeraceae)、路德酵母属(Lodderomyces)、中间念珠菌(Candida intermedia)、念珠菌(Candida sp)。CD患者粪便白念珠菌丰度与粪便钙卫蛋白呈显著正相关(r=0.557,P=0.031)。结论:CD患者肠道真菌菌群与健康人相比发生显著结构变化,真菌物种多样性减小,条件致病真菌如白念珠菌丰度增加,可能参与了疾病进程。

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.