Characteristics of Biofilm-Forming Ability and Antibiotic Resistance of Cutibacterium acnes and Staphylococcus epidermidis from Acne Vulgaris Patients

Introduction: Acne vulgaris (AV) is a common and chronic disorder of the pilosebaceous unit and has a multifactorial pathology, including activities of Cutibacterium acnes (C. acnes) and Staphylococcus epidermidis (S. epidermidis). Antibiotic resistance has become a major concern in dermatology daily practice, and the ability of biofilm formation by both bacteria is suggested to increase antibiotic resistance in acne.

Purpose: Our aim was to analyze the comparison of antibiotic resistance between biofilm-forming (BF) and non-biofilm-forming (NBF) strains of C. acnes and S. epidermidis towards seven antibiotics commonly used for acne.

Methods: This is a cross-sectional analytical study involving 60 patients with AV. Samples were obtained from closed comedones on the forehead using the standardized skin surface biopsy (SSSB) method at the Cosmetic Dermatology Clinic Dr. Hasan Sadikin in Bandung, Indonesia. Isolates were cultured and identified before undergoing the biofilm-forming test using the tissue culture plate method. Antibiotic susceptibility testing for each antibiotic was then performed using the disc diffusion method.

Results: The incidence of antibiotic resistance to clindamycin in BF and NBF C. acnes isolates was 54.5% (p=1.00), while in BF and NBF S. epidermidis isolates, it was 54.5% and 45.5% respectively (p=0.67). The incidence of antibiotic resistance to erythromycin and azithromycin in BF and NBF C. acnes isolates was 54.5% and 63.6% respectively (p=1.00), whereas for S. epidermidis BF and NBF isolates, it was 54.5% (p=1.00). There was no resistance observed to tetracycline, doxycycline, levofloxacin, and cotrimoxazole in all groups.

Conclusion: There were no significant differences in resistance against seven antibiotics between the C. acnes and S. epidermidis in BF and NBF groups. Furthermore, although statistically not significant, some resistances were observed against clindamycin, erythromycin, and azithromycin. Consequently, the use of these three antibiotics should be judiciously regulated.