Background: Gut microbiota plays a significant role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). This study aimed to assess the contribution of gut microbiota dysbiosis to the pathogenesis of NAFLD.

Methods: Forty-seven human feces samples (25 NAFLD patients and 22 healthy subjects) were collected and 16S rDNA amplicon sequencing was conducted on Hiseq 2000 platform. Discrepancy of species composition between controls and NAFLD group was defined by Metastats analysis under P value <0.01.

Results: NAFLD patients harbored lower gut microbiota diversity than healthy subjects did. In comparison to the control group, the Proteobacteria (13.50%) and Fusobacteria (2.76%) phyla were more abundant in NAFLD patients. Additionally, the Lachnospiraceae (21.90%), Enterobacteriaceae (12.02%), Erysipelotrichaceae (3.83%), and Streptococcaceae (1.39%) families, as well as the Escherichia_Shigella (10.84%), Lachnospiraceae_Incertae_Sedis (7.79%), and Blautia (4.95%) genera were enriched in the NAFLD group. However, there was a lower abundance of Prevotella in the NAFLD group than that in the control group (5.83% vs 27.56%, P<0.01). The phylum Bacteroidetes (44.63%) also tended to be more abundant in healthy subjects, and the families Prevotellaceae (28.66%) and Ruminococcaceae (26.44%) followed the same trend. Compared to those without non-alcoholic steatohepatitis (NASH), patients with NASH had higher abundance of genus Blautia (5.82% vs 2.25%; P=0.01) and the corresponding Lachnospiraceae family (24.33% vs 14.21%; P<0.01). Patients with significant fibrosis had a higher abundance of genus Escherichia_Shigella (12.53% vs 1.97%; P<0.01) and the corresponding Enterobacteriaceae family (13.92% vs 2.07%; P<0.01) compared to those with F0/F1 fibrosis.

Conclusions: NAFLD patients and healthy subjects harbor varying gut microbiota. In contrast to the results of previous research on children, decreased levels of Prevotella might be detrimental for adults with NAFLD. The increased level of the genus Blautia, the family Lachnospiraceae, the genus Escherichia_Shigella, and the family Enterobacteriaceae may be a primary contributor to NAFLD progression.