title: Bactericidal activity and post-antibiotic effect of ozenoxacin against Propionibacterium acnes.
abstract: Ozenoxacin, a novel non-fluorinated topical quinolone, is used for the treatment of acne vulgaris in Japan. We investigated bactericidal activity and post-antibiotic effect (PAE) of ozenoxacin against Propionibacterium acnes, a major causative bacterium of acne vulgaris. The minimum inhibitory concentrations (MICs) of ozenoxacin against 3 levofloxacin-susceptible strains (MIC of levofloxacin; ≤4 μg/mL) and 3 levofloxacin-resistant strains (MIC of levofloxacin; ≥8 μg/mL) ranged from 0.03 to 0.06 μg/mL and from 0.25 to 0.5 μg/mL, respectively. These MICs of ozenoxacin were almost the same or lower than nadifloxacin and clindamycin. The minimum bactericidal concentrations (MBCs) of ozenoxacin against the levofloxacin-susceptible and -resistant strains were from 0.06 to 8 μg/mL and from 0.5 to 4 μg/mL, respectively. These MBCs were lower than those of nadifloxacin and clindamycin. In time-kill assay, ozenoxacin at 1/4, 1 and 4 times the respective MIC against both levofloxacin-susceptible and -resistant strains showed a concentration-dependent bactericidal activity. Ozenoxacin at 4 times the MICs against the levofloxacin-susceptible strains showed more potent and more rapid onset of bactericidal activity compared to nadifloxacin and clindamycin at 4 times the respective MICs. The PAEs of ozenoxacin at 4 times the MICs against the levofloxacin-susceptible strains were from 3.3 to 17.1 h, which were almost the same or longer than nadifloxacin and clindamycin. In contrast, the PAEs were hardly induced by any antimicrobial agents against the levofloxacin-resistant strains. The present findings suggest that ozenoxacin has a potent bactericidal activity against both levofloxacin-susceptible and -resistant P. acnes, and a long-lasting PAE against levofloxacin-susceptible 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: kanayama_din@mii.maruho.co.jp.
authors.forename: Shoji
authors.initials: S
authors.lastname: Kanayama
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: Kazuaki
authors.initials: K
authors.lastname: Okamoto
authors.affiliation: Strategic Research Planning & Management Dept., Kyoto R&D Center, Maruho Co., Ltd., Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Ikeda
authors.affiliation: Strategic Research Planning & Management Dept., Kyoto R&D Center, Maruho Co., Ltd., Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Ishii
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: Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Hayashi
authors.affiliation: Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Japan.
authors.forename: Naomasa
authors.initials: N
authors.lastname: Gotoh
mesh_terms: D000631:Aminopyridines / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D064704:Levofloxacin / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D011425:Propionibacterium acnes / Q000187:drug effects*; D015363:Quinolones / Q000494:pharmacology*
chemical_list: D000631:Aminopyridines; D000900:Anti-Bacterial Agents; D015363:Quinolones; D064704:Levofloxacin; C000592413:ozenoxacin
keywords: Bactericidal; MIC; Ozenoxacin; PAE; Propionibacterium acnes; Quinolone