Efficacy of Biofilm Disrupters Against Polymicrobial Biofilms Composed of Candida Spp, Including C. Auris and Staphylococcus Aureus

Background: Candida spp, including C. auris form polymicrobial biofilms (PM) with S. aureus (Sa). It is extremely difficult to eradicate these organisms from open wounds and from environments. Biofilm disrupters (BDs) in the forms of topical gel (Blast X), wound wash (Torrent) solution, and surface disinfectants (SDs) are novel agents with broad spectrum antibacterial and antifungal activity. BDs have been used in the management of chronic wounds and sterilization of environmental surfaces.

Purpose: The goal of this study was to evaluate BDs technology against dual species biofilms of Candida spp, including C. auris and Sa and compare them to chlorhexidine (CHD).

Methodology: We evaluated the various BD agents [topical gel, wound wash solution, and surface disinfectants] and CHD against C. auris, C. albicans 90028 and S. aureus (Sa) by agar plate zone inhibition and time kill assays. The effectiveness of the was evaluated based on the magnitude of the inhibition zone and the reduction of CFU.

Results: All 3 agents and CHD inhibited dual species biofilms composed of C. auris/ Sa and C. albicans/Sa effectively in a concentration dependent manner. All agents completely killed cells in the biofilm. CHD and SD demonstrated the same rapid killing, except Blast X and Torrent yielded 99.99% killing of the fungal cells in the PM biofilm. Additionally, BD agents were highly effective against both C. auris isolates, whereas chlorhexidine was only moderately effective against C. auris 0386, suggesting the possible emergence of resistance/tolerance to CHD in C. auris species.

Conclusions:  All three BD agents and CHD demonstrated excellent activity against dual species biofilms composed of Candida species, including C. auris and Sa. The rapid fungicidal activity of these novel agents will be valuable in eradicating polymicrobial biofilms in chronic wounds with Candida spp, including C. auris, and Sa, thereby accelerating wound closure.