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.

Background/Objectives: 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 Candida albicans and extended-spectrum beta-lactamase (ESBL)-producing E. coli, and the preventive effect of this surfactant impregnated in CVCs on the formation of inter-kingdom biofilms. Methods: 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. Results: Minimum inhibitory concentrations (MICs) for resistant C. albicans ranged from 4-5.3 µg/mL, while for E. coli, 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 C. albicans and 48.7% against E. coli in terms of CFUs. When the CVC was impregnated with the surfactant hydrogel, the effect was improved with an inhibition of 71.7% for C. albicans and 86.7% for E. coli. The images obtained by SEM corroborated the results. Conclusions: C9(LA)2 has potential for use in CVC impregnation to prevent the formation of mixed biofilms of fluconazole-resistant C. albicans and ESBL-producing E. coli.