Although newer azole derivatives such as voriconazole are more effective and have cidal activity against filamentous fungi such Aspergillus fumigatus[36], these derivatives are fungistatic and not fungicidal against pathogenic yeasts. The inability to kill yeasts

leads to resistance to azole in prolonged infections and increases the likelihood that these agents will lack efficacy in severe Candida infections in immunosuppressed patients. Amphotericin B has also been commonly used to treat serious fungal infections, but in contrast to azoles, amphotericin B is fungicidal against yeasts. Nevertheless, resistance to amphotericin B is slowly developing in selected Candida species [37] and there are significant AMN-107 research buy side effects associated with its use, including nephrotoxicity. Although recently developed antifungal agents, including the peptide-based agents’ micafungin and caspofungin, are very promising, resistance to these therapies has already been reported [38–40] and will no doubt become more widespread. The development of resistance to current antifungal agents, the limited efficacy, and the side effects associated with several of these agents increase the importance of continued development of new alternative approaches. The identified Enterococcus faecalis strain produces the antimycotic substance, AZD1152 price ACP, extracellularly. The activity of the ACP was stable upon treatment at different

temperatures, for up to 90°C for 20 min but the activity was lost after boiling and autoclaving. While similar results have been reported for bacillomycin D from B. subtilis[41] and durancin L28-1A from E. durans[42], bacteriocin ST15 from E. faecium was inactivated when subjected to

121°C for Farnesyltransferase 20 min [43]. The antimycotic property of the ACP also remained unaffected in the pH range of 6.0–8.0. At pH values of 5.0 and 9.0, however, the activity was reduced by 50% whereas at values of pH 2.0, 4.0, and 10.0 activity was lost completely. These results are similar to those reported for the bacteriocin produced by E. mundtii[44]. Several bacteriocins produced by enterococci are known to exhibit a wide range of pH stability [45]. The ACP was stable in different organic solvents and surfactants; such stability has been a common feature of many bacteriocins produced by Enterococcus, AMP produced by Bacillus species, and other LAB [43, 46, 47]. The ACP was fully sensitive to proteinase K and partially sensitive to pronase E, confirming its proteinaceous nature. Its resistance to pepsin, lysozyme and trypsin indicated that the anti-Candida active principle may be a cyclic peptide containing unusual amino acids and therefore more resistant to protease hydrolysis [48]. These results suggested that this antimycotic peptide could survive in the intestinal environment and might therefore be administered with food [49].