title: In vitro antimicrobial activity of benzoyl peroxide against Propionibacterium acnes assessed by a novel susceptibility testing method.
abstract: Benzoyl peroxide (BPO), a therapeutic agent for acne vulgaris, was assessed for in vitro antimicrobial activity against Propionibacterium acnes using a novel broth microdilution testing that improved BPO solubility. We searched for a suitable culture medium to measure the minimum inhibitory concentration (MIC) of BPO against P. acnes and finally found the Gifu anaerobic medium (GAM) broth supplemented with 0.1(v/v)% glycerol and 2(v/v)% Tween 80, in which BPO dissolved up to 1250 μg/mL and P. acnes grew well. The MICs and minimum bactericidal concentrations (MBCs) of BPO against 44 clinical isolates of P. acnes collected from Japanese patients with acne vulgaris were determined by our testing method using the supplemented GAM broth. The MICs of BPO were 128 or 256 μg/mL against all isolates of P. acnes regardless of susceptibility to nadifloxacin or clindamycin. The MBCs of BPO were also 128 or 256 μg/mL against the same isolates. Moreover, BPO at the MIC showed a rapid bactericidal activity against P. acnes ATCC11827 in time-kill assay. In conclusion, we could develop a novel assay for the MIC and MBC determinations of BPO against P. acnes, which is reliable and reproducible as a broth microdilution testing and the present results suggest that BPO has a potent bactericidal activity against P. acnes.
authors.affiliation: Drug Development Research Laboratories, Kyoto R&D Center, Maruho Co., Ltd., Japan; Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Japan. Electronic address: okamoto_dix@mii.maruho.co.jp.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Okamoto
authors.affiliation: Drug Development Research Laboratories, Kyoto R&D Center, Maruho Co., Ltd., Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Ikeda
authors.affiliation: Drug Development Research Laboratories, Kyoto R&D Center, Maruho Co., Ltd., Japan; Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Kanayama
authors.affiliation: Drug Development Research Laboratories, Kyoto R&D Center, Maruho Co., Ltd., Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Nakajima
authors.affiliation: Drug Development Research Laboratories, Kyoto R&D Center, Maruho Co., Ltd., Japan.
authors.forename: Tatsumi
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Drug Development Research Laboratories, Kyoto R&D Center, Maruho Co., Ltd., Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Ishii
authors.affiliation: CMC Research Laboratories, Kyoto R&D Center, Maruho Co., Ltd., Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Umehara
authors.affiliation: Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Japan.
authors.forename: Naomasa
authors.initials: N
authors.lastname: Gotoh
authors.affiliation: Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Hayashi
authors.affiliation: Clinical Trial Testing Department, LSI Medience Co., Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Iyoda
authors.affiliation: Clinical Trial Testing Department, LSI Medience Co., Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Matsuzaki
authors.affiliation: Clinical Trial Testing Department, LSI Medience Co., Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Matsumoto
authors.affiliation: Department of Dermatology, Tokyo Women's Medical University, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kawashima
mesh_terms: D000152:Acne Vulgaris / Q000382:microbiology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001585:Benzoyl Peroxide / Q000494:pharmacology*; D003470:Culture Media; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*; D011425:Propionibacterium acnes / Q000187:drug effects* / Q000302:isolation & purification; D015203:Reproducibility of Results
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D001585:Benzoyl Peroxide
keywords: Acne vulgaris; Bactericidal; Benzoyl peroxide; MBC; MIC; Propionibacterium acnes