THE ANTIMICROBIAL EFFECT OF NARROW-BAND UVB (313 NM) AND UVA1 (345-440 NM) RADIATION IN-VITRO

Two new UV lamps were investigated with respect to their antibacterial effectiveness in vitro. Propioni (n=20 strains) and Micrococcaceae (n =16 strains) bacteria extracted from acne patients were applied to RCM and sheep blood agar plates and irradiated with a narrow-band UVB lam p (TL 100W/10R) at a wavelength of 313 nm and a UVA1 lamp (TL 01) at a wavelength of 345-440 nm. The precisely defined energy levels were, i n the case of narrow-band UVB, 0.00, 0.30, 0.50, 1.00, 2.00 and 3.00 J /cm(2) and, in the case of UVA1, 0.00, 2.50, 5.00, 7.50, 10.00 and 20. 00 J/cm(2). UVA1 inhibited neither the growth of Propioni nor Micrococ caceae bacteria. In contrast, the growth of Micrococcaceae was inhibit ed already at a dosage of 0.30 J/cm(2) of narrow-band UVB (P<0.05), hi ghly significant from 0.50 J/cm(2) (P<0.01) and to a maximum of 2.2 po wers of 10 at 3.00 J/cm(2) compared with non-radiated control plates. Propioni bacteria were significantly inhibited at the minimum dosage o f 0.30 J/cm(2) of narrow-band UVB (P<0.01) and to a maximum of 2.8 pow ers of 10 at 3.00 J/cm(2).