Combination Effects of Clindamycin and Benzoyl Peroxide Against <i>Cutibacterium acnes</i>

This study aimed to evaluate the clinical efficacy of combination therapy with clindamycin and benzoyl peroxide in treating acne vulgaris. We assessed the antimicrobial susceptibility of Cutibacterium acnes isolates obtained from these patients. In addition, the potential risk of C. acnes developing resistance to clindamycin and benzoyl peroxide following exposure was investigated in vitro. We analyzed 182 C. acnes isolates from patients with acne to evaluate the clindamycin susceptibility and resistance determinants and to examine the association between topical clindamycin use and resistance. We also tested the resistance frequency of C. acnes to clindamycin monotherapy and clindamycin/benzoyl peroxide combination therapy in vitro. The clindamycin resistance rates in the clindamycin/benzoyl peroxide and clindamycin monotherapy groups were 22.9% and 46.7%, respectively. The combination group showed a significantly lower clindamycin resistance rate (p < 0.05). Under clindamycin monotherapy, resistant strains emerged at a frequency of 8.1 × 10^-8 to 8.7 × 10^-8, whereas no resistant strains were detected under clindamycin/benzoyl peroxide combination conditions. The combination of clindamycin and benzoyl peroxide effectively suppressed the emergence of clindamycin-resistant C. acnes.