Anti-biofilm activity of the metabolites of Streptomyces chrestomyceticus strain ADP4 against Candida albicans

Candida albicans is a commensal but a significant opportunistic pathogen. It forms biofilms, which protect them against anti-Candida compounds. Therefore, an agent capable of disrupting the Candida biofilms will be useful in the treatment of such infections. The metabolites of Streptomyces chrestomyceticus strain ADP4 displayed strong anti-Candida activity, hence were investigated further for their ability to inhibit biofilm. Strong inhibition of biofilms produced by several reference strains of C. albicans was observed with BIC90 values ranging from 4 to 8 μg/mL. The anti-biofilm activity of ADP4 metabolites appeared to involve membrane disruption and leakage of cellular materials. Also, it effectively inhibited Candida cells from adhering to polystyrene surface and inhibited their conversion to the hyphal state, thereby preventing further development of the biofilm by the adherent cells. This is the first such report on the metabolites produced by any strain of S. chrestomyceticus.