The importance of fungal pathogens and antifungal coatings in medical device infections

Abstract

In recent years, increasing evidence has been collated on the contributions of fungal species, particularly Candida, to medical device infections. Fungal species can form biofilms by themselves or by participating in polymicrobial biofilms with bacteria. Thus, there is a clear need for effective preventative measures, such as thin coatings that can be applied onto medical devices to stop the attachment, proliferation, and formation of device-associated biofilms. However, fungi being eukaryotes, the challenge is greater than for bacterial infections because antifungal agents are often toxic towards eukaryotic host cells. Whilst there is extensive literature on antibacterial coatings, a far lesser body of literature exists on surfaces or coatings that prevent attachment and biofilm formation on medical devices by fungal pathogens. Here we review strategies for the design and fabrication of medical devices with antifungal surfaces. We also survey the microbiology literature on fundamental mechanisms by which fungi attach and spread on natural and synthetic surfaces. Research in this field requires close collaboration between biomaterials scientists, microbiologists and clinicians; we consider progress in the molecular understanding of fungal recognition of, and attachment to, suitable surfaces, and of ensuing metabolic changes, to be essential for designing rational approaches towards effective antifungal coatings, rather than empirical trial of coatings.

The Evolutionary Conserved γ-Core Motif Influences the Anti-Candida Activity of the Penicillium chrysogenum Antifungal Protein PAF

“…Besides the occurring drug resistance in C. albicans the biofilm forming ability has great medical relevance. Biofilm formation of C. albicans on medical devices like catheters, dentures, contact lenses, prosthetic joints, and cochlear implants poses a major problem as it can be the source for severe clinical infections ( Giles et al, 2018 ). Furthermore, biofilm formation in the host, e.g., when colonizing the skin and mucosa, hamper effective drug delivery and might favor the development of drug resistance.…”

Rational selection of antifungal drugs to propose a new formulation strategy to control Candida biofilm formation on venous catheters

“…Moreover, biofilm infections involving the tip of the catheter or the external surface and adjacent tissues may contribute to an increase in the failure rate [33,44,49]. Thus, strategies for coating catheters to prevent the initial fixation of fungal (microbial) cells on their surface in order to prevent biofilm from becoming established are important [15].…”

“…Thus, some of the most effective methods for the management of clinically important fungal biofilms are to inhibit the development of the biofilm or to disturb it mechanically [12]. The strategies developed in recent years for its management include (i) the impregnation of the material with antimicrobial substances, such as the antimicrobial lock therapy (ALT) technique, modifying the way the microorganisms will interact with the surface of the material [13][14][15] and (ii) surface coating combining anti-adhesive and antimicrobial properties, as coating using formulations containing antifungal agents makes the surface resistant to infections and, in addition, to acting on the microorganism directly, can greatly reduce the adhesion of Candida spp. on this surface [15,16].…”

“…The strategies developed in recent years for its management include (i) the impregnation of the material with antimicrobial substances, such as the antimicrobial lock therapy (ALT) technique, modifying the way the microorganisms will interact with the surface of the material [13][14][15] and (ii) surface coating combining anti-adhesive and antimicrobial properties, as coating using formulations containing antifungal agents makes the surface resistant to infections and, in addition, to acting on the microorganism directly, can greatly reduce the adhesion of Candida spp. on this surface [15,16]. Examples of this strategy are antifungal formulations containing polymers that form barrier films, since they polymerize and form a film in situ, giving adhesion and resistance, increasing the contact time of the antifungal agent, which allows greater action on the microbial cells [17,18].…”

Ultrashort Self-Assembling Peptide Hydrogel for the Treatment of Fungal Infections

“…Modern medicine has also contributed to an increase in fungal infections directly through the use of medical devices (e.g. catheters), immunosuppressive therapies and antibiotics [3,4]. Candidiasis and aspergillosis are the two most common forms of fungal disease [5].…”