Candida biofilms associated with CVC and medical devices

Intravascular device-related infections are often associated with biofilms (microbial communities encased within polysaccharide-rich extracellular matrix) formed by pathogens on surfaces of these devices. Candida species are the most common fungi isolated from catheter, denture and voice prosthesis-associated infections, and also are commonly isolated from contact lens-related infections (e.g. fungal keratitis). These biofilms exhibit decreased susceptibility to most antimicrobial agents, which contributes to the persistence of infection. Drug resistance in fungal biofilms is multifactorial and phase-dependent, e.g. efflux pumps mediate resistance in biofilms during early phase whereas altered membrane sterol composition contributes to resistance in mature phase. Both substrate type and surface coatings play an important role in the pathogenesis of device-related fungal biofilms. Microarray and proteomic analyses have identified the differentially expressed genes and proteins in Candida biofilms, and recent studies demonstrate that microbial biofilms interact with host immune cells. In this review, we will summarise recent advances in research on fungal biofilms and their relevance to device-associated infections.