Evaluation of the Anti-Candidal Synergistic Activity of Eugenol and Fluconazole and Induction of Necrosis and Apoptosis in Candida krusei Isolates of HIV+ Patients with Oral Candidiasis

Aims: The oral cavity contains more than 200 microbial species. Candida species are also part of the fungal flora of the oral cavity. In recent years, Candida krusei as a common oral candida in AIDS patients, has been shown resistant to some antifungal drugs. The emergence of multidrug-resistant fungi, especially in immunodeficient populations, is a major global problem. Today, the use of medicinal plants and their pure compounds in the treatment of infectious diseases has opened a new horizon for us. The purposes of this study were to investigate the anticandidal Synergistic Activity of Eugenol and Fluconazole and Induction of Necrosis and Apoptosis in Candida krusei (C. krusei) isolates of HIV+ Patients with Oral Candidiasis.  Methods & Materials: The antifungal susceptibility tests using broth microdilution (CLSI, M27-A2) method and the synergy between eugenol and fluconazole using the checkerboard method were performed. Necrotic and apoptotic effects of different antifungal agents against C. krusei were analyzed using flow cytometry method. Findings: In antifungal susceptibility tests by microdilution broth, the mean MIC values of eugenol and fluconazole for C. krusei isolates were 755.06 and 60.1µg/ml, respectively. According to the results of the checkerboard test, eugenol in combination with fluconazole exhibited the significant synergistic effects against most of yeast isolates tested (p<0.05). In fact, eugenol decreased approximately 81.81% of MIC value of fluconazole in growth inhibition of C. krusei. The results of flow cytometry test indicated that eugenol + fluconazole has significant necrotic effects on C. krusei isolates in comparison with control group (p<0.05), while little early and late apoptotic effects of this compound were observed. Conclusion: Eugenol can be used to reduce fluconazole dose, inhibit the growth of fluconazole-resistant C. krusei and the necrosis of yeast cells.