Identification and antibiotic susceptibility profiles of anaerobic bacteria isolated from patients with acne vulgaris

Commensal bacteria like the Staphylococcal species are part of the skin microbiota, which helps maintain healthy skin. However, certain factors can lead to these commensals becoming opportunistic pathogens capable of causing diseases like acne vulgaris. Topical and systemic antibiotics have been the main treatment for acne. However, long-term antibiotic usage could result in the emergence of resistant bacterial strains and treatment failure. This study evaluated the antibiotic susceptibility patterns of anaerobic bacteria isolated from clinical acne samples. Skin swabs were collected from 50 acne patients and cultured under anaerobic conditions. The resulting bacterial isolates were identified using biochemical tests and 16S rRNA gene sequencing. The antibiotic susceptibility patterns of the confirmed isolates were determined using the disc diffusion assay for eight commonly prescribed antibiotics for acne treatment. Sequencing results revealed that S. epidermidis was the most isolated bacterial species (68%, n=34), followed by S. aureus (8%, n=4). However, a significant proportion of bacterial isolates were susceptible to all eight tested antibiotics, which is unusual. On the other hand, 26% (n=13) of the tested bacterial species isolates were found to be resistant to clindamycin, while 36% (18) were resistant to erythromycin and 20% (n=10) were to tetracycline. Since there has been limited research regarding the antibiotic resistance patterns of anaerobic acne-associated bacteria in Malaysia, this study can help shed some light on suitable local prescription practices and raise awareness about the cautious use of antibiotics in treating acne vulgaris.