Preventive Activity of an Arginine-Based Surfactant on the Formation of Mixed Biofilms of Fluconazole-Resistant Candida albicans and Extended-Spectrum-Beta-Lactamase-Producing Escherichia coli on Central Venous Catheters

<b>Background/Objectives:</b> Mixed bloodstream infections associated with central venous catheter (CVC) use are a growing problem. The aim of this study was to evaluate the activity of a cationic arginine-based gemini surfactant, C₉(LA)₂, against mixed biofilms of fluconazole-resistant <i>Candida albicans</i> and extended-spectrum beta-lactamase (ESBL)-producing <i>E. coli</i>, and the preventive effect of this surfactant impregnated in CVCs on the formation of inter-kingdom biofilms. <b>Methods:</b> Broth microdilution assays were performed along with evaluation of the effect against mixed biofilms in formation. The impregnation of CVCs with the surfactant and with a hydrogel containing the cationic surfactant was investigated to assess their potential to prevent the formation of mixed biofilms. Scanning electron microscopy (SEM) was also utilized. <b>Results:</b> Minimum inhibitory concentrations (MICs) for resistant <i>C. albicans</i> ranged from 4-5.3 µg/mL, while for <i>E. coli</i>, the MICs varied from 85.3 to 298.7 µg/mL. Fungicidal and bactericidal action patterns were obtained. In mixed biofilm formation in 96-well plates, there was a significant reduction in the colony-forming unit (CFU) count. The impregnation of the CVC with C₉(LA)₂ alone resulted in a biofilm reduction of 62% versus <i>C. albicans</i> and 48.7% against <i>E. coli</i> in terms of CFUs. When the CVC was impregnated with the surfactant hydrogel, the effect was improved with an inhibition of 71.7% for <i>C. albicans</i> and 86.7% for <i>E. coli</i>. The images obtained by SEM corroborated the results. <b>Conclusions:</b> C₉(LA)₂ has potential for use in CVC impregnation to prevent the formation of mixed biofilms of fluconazole-resistant <i>C. albicans</i> and ESBL-producing <i>E. coli</i>.