Inhibitory effects of cold atmospheric plasma on the growth, ergosterol biosynthesis, and keratinase activity in Trichophyton rubrum.

BACKGROUND: Dermatophytosis is the most important superficial fungal infection which affects nearly 20% of human population worldwide. Recurrence of disease and emerging resistance of Trichophyton rubrum to synthetic antifungals are the main problems in control of dermatophytosis. The purpose of this study was to evaluate the effect of cold atmospheric plasma (CAP) on T. rubrum growth, ergosterol biosynthesis and keratinase activity. METHODS: A CAP system, comprised of helium 98% - oxygen 2% (He/O2), was used. Trichophyton rubrum conidia suspensions were treated with CAP in time periods of 90, 120, 150 and 180 s in 96-well microplates. Fungal growth was evaluated by counting the colony forming unit (CFU). Fungal dry weight, ergosterol biosynthesis and keratinase activity were evaluated in CAP-treated T. rubrum and untreated controls. RESULTS: T. rubrum growth was significantly inhibited by 62%-91%. CAP strongly suppressed fungal ergosterol biosynthesis by 27%-54%. The keratinase activity was increased by 7.30%-21.88% up to 120 s CAP exposure. CONCLUSION: Our results demonstrated for the first time that CAP inhibits T. rubrum growth, suppresses ergosterol biosynthesis and increases moderately keratinase activity in a dose-dependent manner. Overall, CAP exposure could be a potentially useful method for treatment of clinical cases of human and animal dermatophytoses.

Cold atmospheric plasma inhibits the growth of Candida albicans by affecting ergosterol biosynthesis and suppresses the fungal virulence factors in vitro.

BACKGROUND: The pathogenic yeast Candida albicans is the most common opportunistic fungal pathogen that is responsible for a wide array of infections in susceptible individuals. Despite recent progress in developing novel antifungal drugs which combat Candida-related disorders, this fungus is still a major cause of life-threatening infections all over the world. In the present study, the effect of cold atmospheric plasma (CAP) was evaluated on the growth of C. albicans with special attention to the ability of the CAP-treated fungus for biofilm formation, ergosterol biosynthesis and phospholipase and proteinase secretory production. METHODS: C. albicans cell suspensions were irradiated over time-scales ranging of 90, 120, 150 and 180s under cold atmospheric plasma contained He/O2 (2%). Treated and untreated yeast cells were analyzed for the growth, biofilm formation, ergosterol content, and activities of phospholipase and proteinase. RESULTS: Our results showed that CAP remarkably suppressed the growth of C. albicans by 31-82% at the given times. Likewise, CAP strongly inhibited the ergosterol biosynthesis by the fungus in the range of 40-91%, biofilm formation by 43-57% and the activities of phospholipase and proteinase enzymes by 4-45%, dose-dependently. CONCLUSION: CAP strongly inhibits the growth and virulence factors of C. albicans and thus, it could be a potential candidate to treat Candida-related superficial and cutaneous infections in practice.