Disparate Candida albicans Biofilm Formation in Clinical Lipid Emulsions Due to Capric Acid-Mediated Inhibition

Receipt of parenteral nutrition (PN) remains an independent risk factor for developing catheter-related bloodstream infections (CR-BSI) caused by fungi, including by the polymorphic fungus , which is notoriously adept at forming drug-resistant biofilm structures. Among a variety of macronutrients, PN solutions contain lipid emulsions to supply daily essential fats and are often delivered via central venous catheters (CVCs). Therefore, using an biofilm model system, we sought to determine whether various clinical lipid emulsions differentially impacted biofilm growth in We observed that the lipid emulsions Intralipid and Omegaven both stimulated biofilm formation during growth in minimal medium or a macronutrient PN solution. Conversely, Smoflipid inhibited biofilm formation by approximately 50%. Follow-up studies revealed that while Smoflipid did not impair growth, it did significantly inhibit hypha formation and hyphal elongation. Moreover, growth inhibition could be recapitulated in Intralipid when supplemented with capric acid-a fatty acid present in Smoflipid but absent in Intralipid. Capric acid was also found to dose dependently inhibit biofilm formation in PN solutions. This is the first study to directly compare different clinical lipid emulsions for their capacity to affect biofilm growth. Results derived from this study necessitate further research regarding different lipid emulsions and rates of fungus-associated CR-BSIs.