Comparison of fecal microbiota and polyamine concentration in adult patients with intractable atopic dermatitis and healthy adults

Fecal microbiota and polyamine concentration obtained from eleven intractable adult-type atopic dermatitis (AD) patients and thirteen healthy adults were compared. Fecal microbiota were analyzed using terminal-restriction fragment length polymorphism. The fecal microbiota of volunteers were divided into two clusters, A (n = 16) and B (n = 8), and the number of AD patients was found to be higher in Cluster B than Cluster A, suggesting that there are relationships between the obstinacy of intractable adult-type AD and intestinal microbiota in Cluster B. Fecal spermidine concentration in Cluster B were lower than that in Cluster A significantly (P < 0.05). Fecal putrescine concentration in Cluster B also tended to be lower than that in Cluster A. Terminal-restriction fragment (T-RF) of 122 bp generated by digestion with HhaI, which were predicted as unknown bacteria, were detected characteristically in Cluster A. In contrast, T-RFs of 368/9 bp generated by digestion with HhaI, which were predicted as Enterobacteriaceae, were detected characteristically in Cluster B. These bacteria are closely associated with intestinal polyamine concentration. These findings raise the possibility that a low concentration of intestinal polyamines produced by intestinal microbiota is one of the important factors in the onset of intractable adult-type AD.