Candida albicans interaction with Gram-positive bacteria within interkingdom biofilms

Candida albicans is a commensal of the human body and an opportunistic pathogen frequently responsible for nosocomial bloodstream infections. Most of these infections are linked to the development of a biofilm in or on implanted medical devices. C. albicans cells have the capacity to interact with bacteria within biofilms, especially by the way of chemical or metabolic indirect interactions and/or direct physical contacts involving specifically the yeast or hyphal form of the fungal cell, or more rarely involving both forms. According to the species, C. albicans-bacteria interactions can be antagonistic or synergistic, competitive or not. The polymicrobial nature of biofilms may deeply influence the physiopathology of infections as well as the efficiency of antimicrobial agents. The present review aims to focus on the current knowledge of interactions between C. albicans and major Gram-positive bacteria such as Staphylococcus aureus, coagulase negative Staphylococcus, Streptococcus spp. and Clostridium spp. within biofilms. A better understanding of this complicated, fast-paced world of multi-kingdom biofilms will contribute to develop new effective ways to fight biofilm-related infections.