Experimental biofilm-related candida infections

AIM. We investigated the pathogenic role of biofilm and the therapeutic efficacy of anidulafungin in experimental infections of the wax moth Galleria mellonella by C. albicans clinical strains. MATERIALS AND METHODS. On the basis of the in vitro propensity to form biofilm, five biofilm-producer (BP) and four non-producer (NP) C. albicans clinical strains were used in this study. For each strain, we assessed the virulence by infecting G. mellonella larvae and observing survival. Anidulafungin was administered two hours after yeast inoculum at 0.6 μg, according to the therapeutic dose recommended for humans. RESULTS. Biofilm-forming ability highly influenced the larvae-killing rate. A significant (p<0.0001) survival decrease was observed in the BP group, with 80% of the infected larvae dying within 72 hours. NP isolates did not reach the same killing rate, even at the end of experiments (216 h). Larval survival was enhanced (p<0.0001) by anidulafungin administration in both groups. Survival rate at 72 hours was similar in both (BP 78.5% and NP 87.5%), whereas there were still differences at the end of experiments with a higher survival in the NP group (75% versus 48%). CONCLUSIONS. Our data confirm the pathogenic role of biofilm in C. albicans infections. Its importance was further enhanced by lack of contribution of extracellular enzymes, detected in both NP and BP strains. In addition, we demonstrated anidulafungin efficacy in treating biofilm-related invasive candidiasis.