To gain a clear image of the taxonomic changes in obese and NASH gut microbiomes, abundant families and genera with >1% average abundance in any of the groups were examined (Table 2). Within phylum Actinobacteria (Table

2), the only abundant family Bifidobacteriaceae and the only abundant genus Bifidobacterium were differently represented in the study groups. A progressive decreased abundance was observed from the healthy group to the obese group and then to the NASH group. Within phylum Bacteroidetes (Table 2), family Prevotellaceae exhibited a >6-fold increase in the obese group and NASH group, compared to the healthy group, accounting for most of the increased abundance in Bacteroidetes phylum in the obese and NASH groups. Most of the Prevotellaceae sequences belonged to a single-genus Prevotella. Another noteworthy fact selleck chemical in this phylum was that there was a ∼20 fold increase of abundance in the genus Porphyromonas (family Porphyromonadaceae), Ceritinib purchase but statistical significance was not achieved because of the large intragroup variances with the obese group and the NASH group. In contrast, a small, but significant, decrease was observed with Rikenellaceae, in which most of the sequences belonged to a single-genus Alistipes. The decreased representation of Firmicutes in the obese group and the NASH group were mostly explained by the decreased abundance

in two families: Lachanospiraceae and Ruminococcaceae (Table 2). Although most of the genera in these two families exhibited a similar trend (i.e., decreased abundance in the obese group and the NASH group, compared to the healthy group), it is noteworthy that the often pathogenic genus, Clostridium, exhibited similar representation among all groups. Also worth

noting is that the most abundant genera in the Firmicutes Fossariinae phylum, Blautia and Faecalibacterium, showed the greatest reduction in abundance in the obese group and the NASH group. Increased abundance of Proteobacteria in the obese and NASH groups was mainly explained by the increased abundance of Enterobacteriaceae (Table 2). Importantly, Enterobacteriaceae was the only abundant family (within the whole bacteria domain) exhibiting a significant difference between the obese group and the NASH group (Table 2; Fig. 3C). Most of the Enterobacteriaceae sequences belonged to Escherichia (Table 2; Fig. 3D), which is the only abundant genus within the whole bacteria domain exhibiting a significant difference between the obese group and the NASH group. Furthermore, the OTUs within Escherichia were examined. A single OTU was found to dominate the sequences in Escherichia: OTU #20341 was found to account for 83%, 88%, and 90% of the Escherichia sequences in the healthy, obese, and NASH groups, respectively. The representative sequence of this OTU was then used to BLAST against the 16S rRNA sequences (Bacteria and Archaea) on the National Center for Biotechnology Information website (available at: http://blast.ncbi.nlm.nih.gov).