The common skin disease acne vulgaris is caused by Propionibacterium acnes. A lipase secreted by this microorganism metabolizes sebum and the resulting metabolites evoke inflammation in human skin. The antifungal drug ketoconazole inhibits P. acnes lipase activity. We previously showed that the drug also inhibits the growth of P. acnes. Thus, ketoconazole may serve as an alternative treatment for acne vulgaris, which is important because the number of antibioticresistant P. acnes strains has been increasing.Key words ketoconazole, lipase, Propionibacterium acnes.Acne vulgaris, one of the most common skin diseases worldwide, uniquely targets the sebaceous follicles of the face, chest, and back, affecting most adolescents (1). Several factors are involved in the development of acne vulgaris, including hormonal stimulation, increases in the levels of sebum, and bacterial colonization. Microbiologically, the Gram-positive anaerobic bacterium Propionibacterium acnes is responsible for the development of acne vulgaris when overgrowth occurs, although the microorganism is normally a commensal of sebaceous glands. One major virulence factor of the microorganism is a secretory lipase that acts on triglycerides to release free fatty acids (2). Palmitic acid stimulates the toll-like receptor 2-mediated inflammasome, which is associated with the release of interleukin-1, Th17 differentiation, and interleukin-17-mediated keratinocyte proliferation, while oleic acid stimulates adhesion, keratinocyte proliferation, and comedogenesis in P. acnes, also via the release of interleukin-1 (3, 4). Thus, lipase overexpression increases follicular development. Antibacterial agents including clindamycin, minocycline, and doxycycline are standard therapies for acne vulgaris (5). During the last decade, the number of antibiotic-resistant P. acnes strains has gradually increased (6, 7); therefore, a new approach to treatment that does not depend on antimicrobial agents is needed.We found that the antifungal drug ketoconazole potently inhibits P. acnes lipase activity. Five clinical isolates and the type strain (NBRC 107605) were examined. Lipase activity was measured using the 4-methyl umbelliferyl oleate (MUO) assay as described by Niki et al. (8) with some modifications. All strains were grown in brain heart infusion (BHI) broth, and 100 mL cell suspensions (5.0 Â 10 8 cells/mL) in BHI broth supplemented with ketoconazole (Wako Pure Chemical, Osaka, Japan) at final concentrations of 0, 0.125, 0.25 0.5,1, 2, 4, 8, 16, and 32 mg/mL were added to 96-well plates. The plates were incubated anaerobically at 37°C for 24 h. Supernatants (50 mL) were centrifuged and then mixed with 50 mL 0.4 mM MUO (SigmaAldrich, Tokyo, Japan) dissolved in 13 mM Tris-HCl, 0.15 M NaCl, and 1.3 mM CaCl 2 (pH 8.0). The mixtures were incubated for 30 min at 25°C. Enzymatic reactions were terminated by adding 100 mL 0.1 M sodium citrate (pH 4.2). The levels of 4-methylumbelliferone released by the lipase were measured using a fluorometric microplate reader (...

Malassezia are lipophilic yeasts in the skin microbiome that abundantly colonize all parts of human skin except for the soles of the feet. Fungal microbiome analysis of keratotic plugs from the noses of 10 healthy individuals identified Malassezia restricta as the predominant species, followed by Malassezia globosa. Malassezia hyphae were observed in 5 of the 10 individuals. The hyphae were curved and thick-walled with spherical thick-walled and grouped blastoconidia, described as a "spaghetti-andmeatballs" configuration. In this study, we observed Malassezia hyphae in keratotic plugs of healthy subjects, although abundant Malassezia hyphae have previously only been observed in lesional sites of patients with pityriasis versicolor.