Analysis of Bacteroides and Bifidobacterium diversity in fecal samples from patients with type IIdiabetes by using PCR-denaturing gradient gel electrophoresis fingerprint

Objective To analyze the diversity of Bacteroides and Bifidobacterium in type 2 diabetes patients and its difference from that of healthy individuals so as to explore the relation between diabetes and gut predominant microbiota. Methods Bacterial DNAs from type 2 diabetes patients and healthy individuals were extracted from fecal samples and then characterized by PCR-denaturing gradient gel electrophoresis (DGGE) with genus-and group-specific primers targeting 16S rRNA for Bacteroides and Bifidobacterium. After DGGE profilings was obtained,the diversity and similarity analyses were carried out by the number of band,Shannon-Weaver (H'),cluster analysis and the cumulative distribution curve of similarity. Results The range of Shannon-Weaver (H') in diabetes group and healthy group was 0.89(0.75-0.95) and 0.95(0.89-0.97) for Bacteroides; 0.85(0.75-0.94) and 0.87(0.73-0.93) for Bifidobacterium. The cumulative distribution curve of intra-group similarity showed that the Dice similarity coefficient (Cs) lower than (or equal to) 0.5 took up 85.83% of the total Cs for Bacteroides in diabetes group and 35.71% in healthy group; the Cs lower than (or equal to) 0.4 constituted 90% of the total Cs for Bifidobacterium in diabetes group and 60.7% in healthy group. Conclusion DGGE profiling has shown individual specificity in diabetic group and healthy group for Bacteroides and Bifidobacterium. There is no significant distinction in diversity of Bacteroides and Bifidobacterium between the two groups. The intra-group similarity of Bacteroides and Bifidobacterium is lower in diabetic group than in healthy group.