Undesired Effect of Vancomycin Prolonged Treatment: Enhanced Biofilm Production of the Nosocomial Pathogen Candida auris

Abstract

Fungal infections are often consequent to prolonged antibiotic treatments. Vancomycin (Van) is the first-choice antibiotic in the treatment of Staphylococcus aureus infections associated with colonization of catheter surfaces. We demonstrate the direct effect of Van in promoting the formation of the biofilm of the emergent yeast pathogen Candida auris, developed in the conventional polystyrene microwell plate model, as well as on silicone surfaces (22 and 28% increase in total biomass, respectively) and on an S. aures biofilm, residual after vancomycin treatment, where C. auris achieved 99% of the mixed biofilm population. The effect of Van was assessed also in vivo, in the Galleria mellonella infection model, which showed higher mortality when infected with the yeast pathogen in the presence of the antibiotic. This evidence enhances awareness of the potential risk associated with prolonged antibiotic use in promoting fungal infections.

A Re-Purposing Strategy: Sub-Lethal Concentrations of an Eicosanoid Derived from the Omega-3-Polyunsaturated Fatty Acid Resolvin D1 Affect Dual Species Biofilms

“…The long-term (72 h) biofilm was formed as previously described [ 50 ]. In brief, medical-grade silicone platelets (0.5 mm thick) were placed into a 24-well microplate (Novotema S.p.a. Villongo, BE, Italy), and incubated in FBS for 24 h. Then, overnight C. parapsilosis and S. aureus cultures were diluted to 1 × 10 6 cells mL −1 each in TSB-1% glucose mixed and added to the wells at 37 °C for 90 min (adhesion phase).…”