Fig. 4. Relative abundance at different bacterial levels between CSU patients (P) and controls (N) groups was compared. The taxa with significant differences (p < 0.05) were shown including Proteobacteria at phylum level, Bacilli at class level, Enterobacterales at order level, Enterobacteriaceae at family level, Megamonas, Dialister and Megasphaera at genus level.