Abstract
Therapy for candidiasis is becoming problematic due to the toxicities of currently available antifungal agents and the increasing prevalence of resistance among the etiologic agents. Therefore, new antifungals and alternative approaches are needed. In this study, 20 fluconazole-resistant strains of Candida albicans were found to have varying levels of resistance to other azoles, i.e., itraconazole (MIC of 4–128 μg/ml) and ketoconazole (2–256 μg/ml). In addition, 13 of these isolates appeared resistant to amphotericin B (32–128 μg/ml). A total of 21 plant essential oils were screened for their antifungal activity against these multi-drug resistant isolates. The oils of Cymbopogon martini, i.e., citral and cinnamaldehyde, exhibited strong inhibitory activity with minimum inhibitory concentrations (MIC50) ranging from 90–100 μg/ml. The test oils were more effective than fluconazole and amphotericin B in inhibiting azole- and amphotericin B-resistant, as well as amphotericin B-susceptible isolates. The test oils and especially eugenol, exhibited significant synergy with fluconazole or amphotericin B against the test isolates. These findings suggest the possible effective use of certain oils alone or in combination with fluconazole or amphotericin B, against multi-drug resistant isolates of C. albicans.
Acknowledgement
We are thankful to Dr Zehra Mohsin, Department of Gynecology, Jawaharlal Nehru Medical College and Hospital, AMU, Aligarh for providing the clinical samples for isolation of C. albicans. We also acknowledge the Indian Council of Medical Research, New Delhi for providing financial assistance in the form of SRF to M. S. A. Khan.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the manuscript.
This paper was first published online on Early Online on 14 July 2011.