Antifungal-Loaded Calcium Sulfate Beads as a Potential Therapeutic in Combating Candida auris

Abstract

Candida auris provides a substantial global nosocomial threat clinically. With the recent emergence that the organism can readily colonize skin niches, it will likely continue to pose a risk in health care units, particularly to patients undergoing surgery. The purpose of this study was to investigate the efficacy of antifungal-loaded calcium sulfate (CS) beads in combatting C. auris infection. We demonstrate that the CS-packed beads have the potential to interfere with planktonic and sessile C. auris.

Keywords: Candida auris; antimicrobial; antimicrobial activity; biofilm; calcium sulfate; fungal; wound management.

FIG 1

Inhibition of sessile cell viability and fungal biomass by antifungal CS beads. Biofilms were treated with FLZ (80 mg)-, CSP (35 mg)-, and AMB (25 mg)-loaded antifungal beads for 1, 3, and 5 days. The XTT and CV assays were used to assess metabolic activity and biofilm biomass, respectively. Results shown as % viability (A, C, and E) and % biomass (B, D, and F) relative to CS-treated biofilms minus the antifungal. Significant reductions shown as follows: **, P < 0.01; ***, P < 0.001.

FIG 2

Molecular and microscopic assessment of C. auris biofilm inhibition. Biofilms grown on 13-mm Thermanox coverslips were treated with FLZ (80 mg)-, CSP (35 mg)-, and AMB (25 mg)-loaded antifungal beads for 3 days. (A) Following treatment, DNA was extracted and colony forming equivalents determined using qPCR. (B) Scanning electron microscopic images highlight clear reductions in the biofilm bioburden. Significant reductions shown as follows: **, P < 0.01; ***, P < 0.001.

FIG 3

Assessing the efficacy of the antifungal-loaded CS beads in a 3D skin epidermis coculture model. (A) Schematic representation of the coculture skin wound model used for C. auris inoculation and associated treatment. (B) The colony forming equivalents (CFE) for C. auris colonized on the tissue were determined following DNA extraction and qPCR. (C) RNA was extracted from the tissue and the transcriptional gene response in the host was determined using a RT² profiler array containing genes associated with inflammation and fungal recognition. Significant reductions shown as follows: **, P < 0.01; ***, P < 0.001.