Synergistic Inhibitory Effect of Chitosan and Amphotericin B on Planktonic and Biofilm Populations of C. albicans, C. parapsilosis and C. krusei

Many microorganisms readily form microbial biofilms whose resistance to antimicrobial compounds is several orders of magnitude higher than that of the planktonic form. One such genus is the yeast Candida, whose species include both human commensals and opportunistic pathogens that are the cause of many fungal infections. Increasing efforts are therefore made to find substances that could replace currently used drugs, or synergistically interact with them and therefore reinforce their action at an acceptable concentration against both cell suspensions and biofilm populations. We investigated the effect of natural-derived compounds chitosan and a commonly used antibiotic amphotericin B against Candida albicans, C. parapsilosis and C. krusei. Chitosan has proven to be a very effective agent against all Candida species both in suspensions and in biofilm formation and eradication. A combination of chitosan and amphotericin B had a strong synergistic effect even at low concentrations. We achieved the reduction of effective concentration of amphotericin B for inhibition of formation and eradication of Candida spp. biofilm, which may be utilized in medicine as an effective approach in lessening the antibiotic concentrations needed for successful treatment.