Objective        To analyze the features of intestinal microbial community structure in patients with rheumatoid arthritis (RA)

and to investigate the relationship between RA and intestinal flora.       Methods       Fecal samples were collected from 30 patients with RA (RA group) and 21 healthy individuals (control group). The intestinal flora was cultured and the intestinal flora counts were determined. Bacterial DNA was extracted

and the amplicons of the V6-V8 variable regions of bacterial 16S rDNA were analyzed by denaturing gradient gel electrophoresis (DGGE). The richness

Shannon-Wiener index and evenness of the intestinal flora were analyzed after the DGGE profiles were obtained. A distance tree was constructed using clustering analysis with the unweighted pair-group method with arithmetic mean (UPGMA). The structures of the intestinal flora between the RA patients and healthy subjects were compared.       Results       The fecal microbiota of the RA group contained significantly less Bacillus bifidus and Bacteroides fragilis (6.21±1.48  and 6.54±1.28 CFU/ml) than that of the control group did (8.55±0.90 CFU/ml and 8.73±0.90 CFU/ml

P0.01)

while the counts of Lactobacillus

Clostridium

Enterobacter and Enterococci were not significantly altered (P0.05). As compared with the control group (richness: 22.8±3.12

Shannon-Wiener: 2.98±0.26 and evenness: 0.96±0.05)

the richness (16.0±1.05

P0.01)

Shannon-Wiener (2.48±0.14

P0.01) and evenness (0.90±0.05

P0.01) of the RA group significantly reduced

suggesting the number of bacterial species (richness)

the diversity of total bacteria and their relative abundance (evenness) in the RA patients decreased remarkably. Moreover

some bands were not detected in the DGGE profile of the RA group. In the cluster analysis of the DGGE profiles

two clusters were found in 20 samples. One cluster included 10 RA samples and 1 control samples

and another cluster contained 9 control samples. It represented high similarity in the same sample group

but low similarity between different groups.       Conclusion       Enteric dysbacteriosis is detected in patients with early RA

and remarkable differences are observed in intestinal microflora between RA patients and healthy individuals. The changes of intestinal flora may be related to the pathogenesis of RA.