Time-Lapse Tracking of Candida tropicalis Biofilm Formation and the Antifungal Efficacy of Liposomal Amphotericin B.

Candida species bloodstream infection, or candidemia, remains an important health issue with high morbidity and mortality. Bloodstream infections caused by Candida species are often associated with the ability of Candida to form biofilms on medical devices, such as central venous catheters. Non-albicans Candida species have been increasing gradually in clinical settings. Another Candida species, C. tropicalis, has a propensity to form biofilms and is also an independent risk factor for high morbidity and mortality in hospitalized patients. This study was conducted to investigate the process of biofilm formation by C. tropicalis and the antifungal activity of liposomal amphotericin B (LAB) against both forming biofilms and developed biofilms using time-lapse imaging. We found that C. tropicalis has a high capacity for hyphal growth and gas generation due to its high metabolic activity. Thus, we visually observed the formation of aggressive C. tropicalis biofilms, which are fast-growing biofilms. We found that LAB acts immediately and completely inhibits forming biofilms. Furthermore, we demonstrated that LAB was effective against developed C. tropicalis biofilms by reducing the growth of hyphae and morphological changes. These results suggest that LAB may be effective for the treatment of infections caused by catheter-related C. tropicalis biofilms.