Author(s): Aditi Jha, Timothy Barkham, Siew Pang Chan, Audrey WH Tan, Mark BY Tang, Hiok Hee Tan, Mark JA Koh, Shang-Ian Tee and Virlynn Tan
Background: The increasing use of antibiotics for acne has led to the development antibiotic resistant propionobacteria and has become a worldwide problem in the recent years.
Objective: We investigated the prevalence and pattern of antibiotic resistance to Cutibacterium acnes (C. acnes) and its relation to previous antibiotic therapy in acne patients attending the dermatology outpatient clinic in a tertiary dermatological referral Centre in Singapore.
Methods: Skin swabs were collected from the skin lesions in 402 acne patients at baseline, 2months and 4 months. Cultures for C. acnes were done and sensitivity testing of the isolates was done using 5 commonly used antibiotics, namely tetracycline, minocycline, doxycycline, erythromycin and clindamycin. Data was collected about the previous treatment and current treatment being prescribed from Centre during these visits.
Results: Cutibacterium acnes were isolated in 241 (60%) acne patients at baseline. Sixty seven (28.5%) of 235 isolates were resistant to at least one antibiotic. Clindamycin resistance was most common (n=64, 27.2%), followed by erythromycin (n=63, 26.8%), doxycycline (n=22, 9.4%), tetracycline (n=14, 6.0%) and minocycline (n=4, 1.7%). Previous use of antibiotics was significantly more in patients with resistant strains of C. acne (59.7%) as compared to those who had sensitive strains (44.0%) (P=0.03). Individually, the use of oral erythromycin and minocycline was significantly more in patients who harbored resistant strains (23.9% vs. 8.9%; P<0.01: 9.0% vs. 2.4%; P=0.04 respectively). There was no significant difference in the acne severity between the patients who had resistant P. acne strains versus those who had sensitive strains.
Conclusion: Antibiotic resistant C. acnes are prevalent in Singapore. Clindamycin and erythromycin resistance were most commonly seen among the resistant strains. Past history of antibiotic use especially erythromycin and minocycline was commonly seen among the patients who harbored resistant strains.