A total of 118 patients with type 2 diabetes mellitus were divided into acarbose treatment group ( A group,n =58 ) and no acarbose treatment group ( B group,n =60),and 57 healthy subjects were used as control group (C group).The quantification of fecal bifidobacteria and enterococcus faecalis in these subjects was made by realtime PCR.The results showed that fecal bifidobacteria contents in A and B groups were lower and enterococcus faecalis contents were higher compared with C group.After four weeks of intervention,fecal bifidobacteria contents in A and B groups increased ( P＜0.01 ),especially in A group,while enterococcus faecalis contents decreased ( P＜0.05 )compared with the baseline.Univariate correlation analysis showed that bifidobacteria content was negatively associated with lipopolysaccharides(LPS),advanced glycation index,high sensitive C reactive protein ( hs-CRP),and body mass index ( BMI ) at baseline ( P＜0.05 or P＜0.01 ).The enterococcus faecalis content was positively associated with levels of monocyte chemoattractant protein-1,LPS,tumor necrosis factor-α,hs-CRP,plasminogen activator inhibitor-1,BMI,and HbA1c (P ＜0.01 ).After four weeks of intervention,the above associations disappeared.Stepwise multivariate regression showed that basal BMI,HbA1c,and age contributed to the increase in the number of enterococcus faecalis,and BMI negatively contributed to the decrease in number of bifidobacteria.