Combining Miconazole and Domiphen Bromide Results in Excess of Reactive Oxygen Species and Killing of Biofilm Cells.

Jana Tits,Bruno P A Cammue,Judith Berman,Karin Thevissen

doi:10.3389/fcell.2020.617214

Jana Tits, Bruno P A Cammue + Show 2 more

Open Access

https://doi.org/10.3389/fcell.2020.617214

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Abstract

Fungal biofilm-related infections are increasingly occurring. We previously identified a fungicidal antibiofilm combination, consisting of miconazole (MCZ) and the quaternary ammonium compound domiphen bromide (DB). DB eliminates tolerance rather than altering the susceptibility to MCZ of various Candida spp. Here we studied the mode of action of the MCZ-DB combination in more detail. We found that DB's action increases the permeability of the plasma membrane as well as that of the vacuolar membrane of Candida spp. Furthermore, the addition of DB affects the intracellular azole distribution. MCZ is a fungicidal azole that, apart from its well-known inhibition of ergosterol biosynthesis, also induces accumulation of reactive oxygen species (ROS). Interestingly, the MCZ-DB combination induced significantly more ROS in C. albicans biofilms as compared to single compound treatment. Co-administration of the antioxidant ascorbic acid resulted in abolishment of the ROS generated by MCZ-DB combination as well as its fungicidal action. In conclusion, increased intracellular MCZ availability due to DB's action results in excess of ROS and enhanced fungal cell killing.

Highlights

Various human body parts, like the oral cavity and reproductive organs, as well as implanted medical devices are potential substrates for fungal biofilm formation (Harriott et al, 2010; Rautemaa and Ramage, 2011; Ramage and Williams, 2013; Gökmanoglu et al, 2018)
To determine whether a treatment is fungicidal against (i) biofilms or (ii) planktonic cultures in stationary phase of C. albicans SC5314 or C. glabrata BG2, a fungicidal activity assay was performed as described in Tits et al (2020). (i) Briefly, C. albicans or C. glabrata overnight cultures were diluted to an optical density at 600 nm (OD600nm) of 0.1 in RPMI 1640 medium, followed by biofilm growth in a 100 μL volume at 37◦C
As imidazoles like ketoconazole can be potentiated by domiphen bromide (DB) (Tits et al, 2020), we used FKD as a tool to study the mode of action of a DB-azole combination against Candida spp

Summary

Introduction

Like the oral cavity and reproductive organs, as well as implanted medical devices are potential substrates for fungal biofilm formation (Harriott et al, 2010; Rautemaa and Ramage, 2011; Ramage and Williams, 2013; Gökmanoglu et al, 2018). Species from the genus Candida, of which Candida albicans is the most common, are a frequent cause of opportunistic biofilm-related infections, which affect an increasing amount of people due to the rising number of immunocompromised people and patients with implanted medical devices (Kojic and Darouiche, 2004; Cauda, 2009; Rautemaa and Ramage, 2011; Tumbarello et al, 2012; Lebeaux et al, 2014). A valid alternative to the search for new types of antibiofilm drugs is the combination of a conventional antimycotic with a potentiator that increases the activity of the antimycotic against biofilms. MCZ belongs to the azole type of antifungals, which is the preferred antifungal drug class for topical treatment of mucosal biofilm-related Candida infections (Gavarkar et al, 2013). The fungicidal imidazole MCZ induces the accumulation of reactive oxygen species, resulting in killing of Candida cells (Kobayashi et al, 2002; François et al, 2006)

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