Counter-Acting <i>Candida albicans</i>-<i>Staphylococcus aureus</i> Mixed Biofilm on Titanium Implants Using Microbial Biosurfactants

• Main Authors: Erica Tambone, Alice Marchetti, Chiara Ceresa, Federico Piccoli, Adriano Anesi, Giandomenico Nollo, Iole Caola, Michela Bosetti, Letizia Fracchia, Paolo Ghensi, Francesco Tessarolo
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Polymers
• Subjects: titanium coating; anti-biofilm coating; biosurfactants; mixed biofilm; <i>Staphylococcus aureus</i>; <i>Candida albicans</i>
• Online Access: https://www.mdpi.com/2073-4360/13/15/2420

This study aimed to grow a fungal-bacterial mixed biofilm on medical-grade titanium and assess the ability of the biosurfactant R89 (R89BS) coating to inhibit biofilm formation. Coated titanium discs (TDs) were obtained by physical absorption of R89BS. <i>Candida albicans</i>-<i>Staphylococcus aureus</i> biofilm on TDs was grown in Yeast Nitrogen Base, supplemented with dextrose and fetal bovine serum, renewing growth medium every 24 h and incubating at 37 °C under agitation. The anti-biofilm activity was evaluated by quantifying total biomass, microbial metabolic activity and microbial viability at 24, 48, and 72 h on coated and uncoated TDs. Scanning electron microscopy was used to evaluate biofilm architecture. R89BS cytotoxicity on human primary osteoblasts was assayed on solutions at concentrations from 0 to 200 μg/mL and using eluates from coated TDs. Mixed biofilm was significantly inhibited by R89BS coating, with similar effects on biofilm biomass, cell metabolic activity and cell viability. A biofilm inhibition >90% was observed at 24 h. A lower but significant inhibition was still present at 48 h of incubation. Viability tests on primary osteoblasts showed no cytotoxicity of coated TDs. R89BS coating was effective in reducing <i>C. albicans-S. aureus</i> mixed biofilm on titanium surfaces and is a promising strategy to prevent dental implants microbial colonization.