Inhibition of Candida albicans adhesion on medical-grade silicone by a Lactobacillus-derived biosurfactant

Aims: The study aimed at investigating the ability of biosurfactant (BS) produced by a Lactobacillus brevis isolate (CV8LAC) to inhibit adhesion and biofilm formation of Candida albicans on medical-grade silicone elastomeric disks (SEDs). Methods and Results: Biosurfactant activity was evaluated at physiological conditions, by means of co-incubation and precoating assays. Additionally, BS extract was tested for antifungal susceptibility against C. albicans in both planktonic and sessile form. Biofilm covered surface and hyphae and blastospores occurrence were quantified by scanning electron microscopy (SEM) and image analysis. BS did not inhibit growth of C. albicans in both planktonic and sessile form. Nevertheless, co-incubation with 2000 μg ml^-1 BS significantly reduced biofilm formation on SEDs surface by 89, 90 and 90% after 24, 48 and 72 h of incubation. Fungal adhesion and biofilm formation to precoated SEDs was reduced by 62, 53, 50 and 44% after 1·5, 24, 48 and 72 h. SEM showed a significant reduction of biofilm covered surface in precoated disks but no differences in the production of hyphae or blastospores, except at 1·5 h of incubation. Conclusions: This study demonstrated that CV8LAC BS has the ability to counteract significantly the initial deposition of C. albicans to silicone surfaces and to effectively slow biofilm growth. Significance and Impact of the Study: The anti-adhesive properties of the CV8LAC BS suggest a potential role of the coating for preventing fungal infection associated to silicone medical devices.