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

Abstract

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 Candida albicans, 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 in vitro biofilm model system, we sought to determine whether various clinical lipid emulsions differentially impacted biofilm growth in C. albicans. We observed that the lipid emulsions Intralipid and Omegaven both stimulated C. albicans biofilm formation during growth in minimal medium or a macronutrient PN solution. Conversely, Smoflipid inhibited C. albicans biofilm formation by approximately 50%. Follow-up studies revealed that while Smoflipid did not impair C. albicans 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 C. albicans biofilm formation in PN solutions. This is the first study to directly compare different clinical lipid emulsions for their capacity to affect C. albicans biofilm growth. Results derived from this study necessitate further research regarding different lipid emulsions and rates of fungus-associated CR-BSIs.

Extracellular Vesicles Regulate Biofilm Formation and Yeast-to-Hypha Differentiation in Candida albicans

“…Murzyn and colleagues ( 63 ) have shown that purified C 10:0 inhibited C. albicans filamentation and reduced its capacity to adhere and form biofilm. Willems and colleagues ( 64 ) have confirmed the inhibitory activities of C 10:0 incorporated in lipid emulsions. Notably, in both studies, C 10:0 did not suppress yeast growth.…”

Effects of lipid emulsions on the formation of Escherichia coli–Candida albicans mixed-species biofilms on PVC

“…However, our findings are supported by other studies. These studies have proven that C. albicans has a unique sensitivity to medium-chain fatty acids with carbon chain lengths of C8, C10, and C12, represented by caprylic, capric, and lauric acid, respectively 29,30 . The abovementioned medium-chain fatty acids have been demonstrated to have antifungal effects 31,32 .…”

Effects of lipid emulsion on the formation of Escherichia coli –Candida albicans mixed species biofilm on PVC

“…Swindell K. pointed out that 10% of lipid emulsion was conducive to the germination of Ca spores and the growth of mycelia (18). The spores and mycelia of Ca could provide a lot of adhesion sites for E. coli, meanwhile, lipid emulsion provided rich nutrients, and promoted the growth of pathogenic bacteria and bio lm formation, which may partly explain why lipid emulsion has a catalytic effect on E. coli-Ca mixed bio lm formation 35 . hDC mainly regulates the biosynthesis of E.coli agellum, bacterial division, and the expression of bacterial virulence genes 36 .…”