Antifungal efficacy of pure boron on yeast and mold isolates causing superficial mycosis

OBJECTIVE: To examine the in vitro antifungal effects of water-soluble pure elemental boron with an alkaline solution against Candida species, Trichophyton species, and Aspergillus fumigatus that cause superficial mycosis. METHODS: The study was conducted at the microbiology laboratory of Kahramanmaras Sutcu Imam University Hospital, Kahramanmaras, Turkey, from June to December 2018, and comprised fungal strains isolated from patients with superficial mycosis who visited the dermatology clinic. The in vitro antifungal effects of the boron solution at various concentrations were determined using the microbroth dilution method. Candida albicans ATTC 90028 and Candida albicans MYA 274 served as the quality control strains, while fluconazole and amphotericin B were used as comparator antifungal agents. Data was analysed using SPSS 22. RESULTS: Of the 58 strains, 28(48.3%) were Candida albicans, 9(15.5%) non-Candida albicans, 12(20.7%) Trichophyton rubrum, 4(6.9%) Trichophyton mentagrophytes, 2(3.4%) Trichophyton species and 3(5.2%) were Aspergillus fumigates. Boron at a concentration of 78.125 μg/mL inhibited the growth of Candida albicans. The 50% and 90% minimum inhibitory concentrations of the solution in non-Candida albicanswere 78.125 and 312.5 μg/mL, respectively, whereas those in Trichophyton rubrum were 312.5 and 625 μg/mL, respectively. The 50% minimum inhibitory concentration of the solution in Aspergillus fumigatus was 625 μg/mL, whereas the 90% minimum inhibitory concentration could not be determined. CONCLUSIONS: Boron is an inexpensive, non-antibiotic element with potential uses as an antifungal agent.