Microorganisms Isolated from Acne and Their Antibiotic Susceptibility

Ki, Ho Gyun; Yun, Sook Jung; Lee, Jee Bum; Kim, Seong Jin; Lee, Seung Chul; Won, Young Ho

Abstract

BACKGROUND
The representative organism isolated from acne lesion is Propionibacterium acnes (P. acnes), but other organisms, such as Staphylococcus epidermidis (S. epidermidis), have also been isolated. These organisms play an important role in the inflammatory process, therefore, we usually treat the inflammatory acne with antibiotics. However, long term use of antibiotics may result in development of resistant strains and treatment failure. In these cases, antibiotic susceptibility test may be helpful. OBJECTIVE: The purpose of this study was to investigate microorganisms isolated from acne and their antibiotic susceptibility METHOD: We examined the species of bacteria aerobically and anaerobically isolated from 41 patients (38 acne patients and 3 acneiform eruption patients) and determined the antimicrobial susceptibilities of P. acnes and S. epidermidis. For P. acnes, we measured the minimal inhibitory concentration(MIC) of tetracycline by using E test. RESULT: Among the bacteria isolated, P. acnes (18 patients) was the most common, followed by S. epidermidis (14 patients). The MICs of tetracycline ranged from 0.016 to 0.380 microgram/ml, and 94.1% were inhibited by < or = 0.094 microgram/ml of tetracycline. The tetracycline MICs of P. acnes isolates were significantly lower when isolates came from patients whose acne duration was less than 2 years. The isolation rate of P. acnes was significantly higher in pustule lesions compared to non-pustule lesions. In antibiotic susceptibility test for S. epidermidis, the resistance rate of ofloxacin, erythromycin, clindamycin and tetracycline was 14.3%, 35.7%, 21.4% and 50.0% respectively. CONCLUSION: We confirmed that representative organisms isolated from acne lesions were P. acnes and S. epidermidis, and that the ranges of tetracycline MICs for P. acnes were low, thus suggesting that the appearance of resistant strains of P. acnes is not yet common. On the other hand, the resistance rate of S. epidermidis was relatively high. Therefore when we use antibiotics for acne patients, we should keep in mind that the appearance of resistant strain is possible and antibiotic susceptibility should be checked.