Antimicrobial effects of phototherapy and photochemotherapy in vivo and in vitro

Abstract

We investigated the antimicrobial effects of phototherapy and photochemotherapy in vivo and in vitro. First. Staphijlococeus aitreus samples were obtained using stamp agar medium from inflammatory lesions of 29 adult patients with atopic dermatitis before and after a single photo-chemotherapy. Therapy was oral PUVA (30 mg 8-methoxypsoralen. 8M0P plus 5J/cm^UVA). topical PUVA (0-3% 8M0P plus 2()()m]/cm^UVA) or UVB (8{)mJ/cm') irradiation. The number of 5. aureus on the lesions was signiticantly reduced, even after a single treatment with all therapies. Reductions (meaniSD) were f)9-3±269%. 76-3±31-3% and 83-8±18-5%. respectively. Secondly, we investigated the effect of PUVA (0-001% 8M0P plus 10. 20, 30. 40. or 5()mJ/cm^ UVA) and UVB (10. 30. 50. or lOOmJ/cm') irradiation on the proliferation of 5. aureus in vitro. PUVA and UVB treatment markedly inhibited the proliferation in a dose-dependent manner. These results seem to indicate the possibility that the antimicrobial effect of UV radiation contributes to successful photochemotherapy in patients with atopic dermatitis.