Original papers
The role of benzoyl peroxide in prevention of development of antibiotic-resistant Propionibacterium acnes during combined treatment with erythromycin and tretinoin

Introduction: Acne vulgaris is one of the commonest skin diseases, affecting almost 80% of adolescents and young adults aged 11 to 30. According to some authors the prevalence is 100%, individuals differing only in severity of expression. Acne lesions involve the pilosebaceous unit of the seborrhoeic rich areas, such as the face, back and chest (although occasionally it may be more widespread). The first report of resistance to anti-acne antibiotics in cutaneous propionibacteria appeared in the early 1980s. The emergence of resistance coincided with the introduction of topical antibiotic formulations.
Aims: The objectives of the study were to determine: (1) the prevalence of skin colonization by propionibacteria resistant to erythromycin among acne patients of the Spa Dermatological Clinic in Iwonicz Zdrój, (2) the development of antibiotic resistance during the 12-week treatment by different topical medications, (3) the role of topical benzoyl peroxide in prevention of development of antibiotic-resistant Propionibacterium acnes during combined treatment with erythromycin and tretinoin.
Material and methods: Sixty patients of both sexes between the age of 16 and 26 suffering from mild to moderate acne (Leeds scale 2-6) were classified in 3 groups (20 in each). The first group was treated with topical 4% erythromycin, the second group with 4% erythromycin and 0.025% tretinoin, and the third group with 4% erythromycin and 0.025% tretinoin + benzoyl peroxide once every two days.
Results: The results show that there are no statistically significant differences between the groups in prevalence of skin colonization by propionibacteria resistant to erythromycin. Twelve-week treatment with a topical antibiotic does not develop the antibiotic resistance of P. acnes. All groups show good efficacy. Intermittent irritation was observed in the patients who received the combined therapy.