Acne is one of the most frequent skin diseases of the population aged 11 to 30 years. The participation of microorganisms in the development and persistence of the inflammation in acne is more than probable. The objective of the present study was to investigate the bacterial colonization of skin lesions in patients with severe forms of acne, its sensitivity to selected antimicrobial drugs and to test the effect of a standardized extract from the plant Mahonia aquifolium on selected bacterial strains in vitro. Material from skin lesions of 24 patients with acne treated at the Department of Dermatology of the Faculty Hospital in Bratislava was collected on the first day of hospitalization. After cultivation and identification of isolated microorganisms their sensitivity to antimicrobial drugs was tested. Propionibacterium acnes strain was isolated from 20 patients: one strain was resistant to erythromycin and clindamycin. Of 40 isolated strains of coagulase-negative staphylococci 7 were not sensitive to tetracycline, 21 to erythromycin, 14 to clindamycin and 13 to cotrimoxazol. There was isolated one strain of Micrococcus sp., one strain of Corynebacterium sp. and one strain of Enterobac- ter agglomerans. For testing of the activity of Mahonia aquifolium extract 20 strains of P. acnes and 20 strains of coagulase-negative staphylococci were selected. The tested extract inhibited and inactivated all tested strains of P. acnes in a 0.5 to 1% concentration (which corresponds to 25 to 50 mg of alkaloids calculated as berberine/ml) and 17 strains of coagulase-negative staphylococci in a 2 to 20% concen- tration (which corresponds to 100 to 500 mg of alkaloids/ml). The in vitro results suggest that after successful clinical studies extract from Mahonia aquifolium may be used in an appropriate form as a supportive agent in a complex therapy of acne.

        Key words: Propionibacterium acnes - coagulase-negative staphylococci - Mahonia aquifolium