Anti-Candida Activity of Biosurfactant Produced by Rhodotorula paludigena

Abstract

Background: Biosurfactants are natural extracellular products that are produced by several microorganisms. These compounds are highly developed during recent years for industrial, medical, and environmental applications. Although, the majority of microbial biosurfactants were originated from bacterial species, some studies have shown that Rhodotorula muciliginosa and Candida rugosa are fungal sources for biosurfactants production. The aim of the present study was to evaluate anti- Candida activity of biosurfactant produced by R. paludigena. In addition, the combination of biosurfactant and several antifungal drugs was also investigated against Candida isolates. Materials and Methods: In the present study, R. paludigena was subjected for the production of biosurfactant and yielded product was confirmed using several specific tests. Biosurfactant was produced using Sabouraud dextrose broth at 29°C for 5-7 days. Cell-free supernatants were collected and extracted using chloroform-methanol solvent. Checkerboard microdilution method was used to assess antifungal susceptibility and combination interaction. Results: Out of 80 suspected isolates to Rhodotorula, only one strain (R. paludigena) has been found to be predominant for biosurfactant production. Our results show that produced biosurfactant has anti- Candida activity at the range of 1-8 mg/mL. Furthermore, it showed a synergistic effect with antifungal drugs caspofungin. Conclusion: It is concluded that R. paludigena has great potential for biosurfactant production with valuable antifungal effect against C. albicans. On the other hand, the synergistic effect was found when a combination of biosurfactant and caspofungin were applied against C. albicans. Keywords: Antifungal drugs, biosurfactant, Candida albicans, combination therapy, synergistic effect.