In vitro evaluation of the acquisition of resistance, antifungal activity and synergism of Brazilian red propolis with antifungal drugs on Candida spp

Abstract

Aims: To evaluate the ability of Candida parapsilosis and Candida glabrata to develop phenotypic resistance to a benzophenone enriched fraction obtained from Brazilian red propolis (BZP-BRP) as compared to fluconazole (FLC). To investigate possible synergy between BZP-BRP and FLC and anidulafungin (AND).

Methods and results: To analyse the development of resistance, isolates susceptible to these antifungals were cultured in increasing concentrations of FLC and BZP-BRP. The increase in FLC minimum inhibitory concentration for all isolates was evident and the majority developed resistance, whereas none isolated became less susceptible to BZP-BRP. Synergism was investigated by checkerboard method. BZP-BRP demonstrated synergy with FLC and indifference with AND for most isolates.

Conclusions: In conclusion, the synergism observed with FLC suggests that BZP-BRP could be a possible therapeutic strategy for the treatment of infections related to FLC-resistant Candida sp.

Significance and impact of the study: The indiscriminate use of antifungals results in the emergence of drug-resistant strains among previously susceptible populations. BZP-BRP can become an alternative for the treatment of persistent infections caused by Candida sp.

Keywords: Brazilian red propolis; Candida; antifungal agent; fluconazole; resistance; synergism.