ANTIMICROBIAL EFFECTS OF PHOTOTHERAPY AND PHOTOCHEMOTHERAPY IN-VIVO AND IN-VITRO

We investigated the antimicrobial effects of phototherapy and photoche motherapy in vivo and in vitro. First, Staphylococcus aureus samples w ere obtained using stamp agar medium from inflammatory lesions of 29 a dult patients with atopic dermatitis before and after a single photoch emotherapy. Therapy was oral PUVA (30 mg 8-methoxypsoralen, 8MOP plus 5 J/cm(2) UVA), topical PUVA (0.3% 8MOP plus 200 mJ/cm(2) UVA) or UVB (80 mJ/cm(2)) irradiation. The number of S. aureus on the lesions was significantly reduced, even after a single treatment with all therapie s. Reductions (mean+/-SD) were 69.3+/-26.9%, 76.3+/-31.3% and 83.8+/-1 8.5%, respectively. Secondly, we investigated the effect of PUVA (0.00 1% 8MOP plus 10, 20, 30, 40, or 50 mJ/cm(2) UVA) and UVB (10, 30, 50, or 100 mJ/cm(2)) irradiation on the proliferation of S. aureus in vitr o. PUVA and UVB treatment markedly inhibited the proliferation in a do se-dependent manner. These results seem to indicate the possibility th at the antimicrobial effect of UV radiation contributes to successful photochemotherapy in patients with atopic dermatitis.