In vitro biofilm formation of Candida albicans and non-albicans Candida species under dynamic and anaerobic conditions

An understanding of biofilm behavior of Candida species under different environmental conditions is key to the development of effective preventive measures for candidal infections. Hence in this study we assessed the impact of the environmental milieu on Candida biofilm formation using polystyrene, flat-bottomed 96-well microtiter plates. A total of 20, comprising 10 clinical isolates each of Candida albicans and, non-albicans species of Candida were compared for their biofilm forming ability both under aerobic and anaerobic conditions, and static and dynamic conditions. XTT reduction assay was used to quantify the sessile growth. Biofilm formation of all 10 C. albicans isolates differed significantly between dynamic and static states under both atmospheric conditions (P < 0.05). For non-albicans Candida species, a significant difference in biofilm growth between dynamic and static states was noted only when incubated aerobically (P < 0.05), and no significant difference in biofilm formation was noted between aerobic and anaerobic conditions. Scanning electron microscopy revealed that C. albicans produced a compact multilayered biofilm embedded in noticeably higher quantity of extracellular polymeric matrix in aerobic/dynamic conditions compared with anaerobic/static conditions. Our data indicate that biofilm formation of C. albicans and non-albicans Candida species is modulated by hydrodynamic conditions and ambient oxygen gradients. However, further work is required to fully elucidate how Candida biofilms persist within the oral milieu under such challenging ecological pressures.