“…At the phylum level, 6/14 studies showed an increase [26,29,32,33,31,34], while 3/14 reported a decrease [25,35,36] in Firmicutes phylum in psoriatic patients compared to the healthy control group. The number of bacteria belonging to the Bacteroidetes phylum was increased in psoriatic patients only in two studies, while 5/11 studies indicated a decrease [37,26,32,33,31].…”