Evaluation and comparison of antifungal effect of voriconazole with nystatin on candida species derived from neoplastic patients undergoing maxillofacial radiotherapy.

Background: Radiotherapy is a common treatment for head-and-neck malignancies and causes complications such as oral candidiasis and the change of oral Candida species from albicans to nonalbicans. Voriconazole has acceptable antifungal effect. The aim of this study was to determine and compare the antifungal effect of nystatin with voriconazole on these species. Materials and Methods: The samples used in this in vitro study were identified by polymerase chain reaction-restriction fragment length polymorphism from patients before and 2 weeks after head-and-neck radiotherapy in Seyed Al-Shohada Hospital. The antifungal effect of nystatin and voriconazole was determined by microdilution method and measurement of the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration, and the results were analyzed by Mann-Whitney analysis. Results: The results showed that all species before and after radiotherapy showed 100% sensitivity to nystatin. Prior to radiotherapy, 57.1% of albicans species isolated were in the sensitive range (MIC ≤1) and 42.9% were in the dose-dependent range (MIC = 2) to voriconazole. After radiotherapy, 58.3% of albicans species were in the sensitive range and 41.7% of these species were in the dose-dependent range to voriconazole. Conclusion: The results of the present study showed that before radiotherapy, all species were sensitive to nystatin, while a percentage of albicans and nonalbicans were resistant to voriconazole. In the 2nd week of radiotherapy similar to prior to radiotherapy, all species isolated from patients were sensitive to nystatin, while a percentage of albicans and nonalbicans were resistant to voriconazole.

Comparison of oral candidiasis characteristics in head-and-neck cancer patients before and during radiotherapy.

Background: Patients undergoing head-and-neck radiotherapy are susceptible to Candida colonization and infection. This study aimed to identify oral Candida species type (ST), colony count (CC), and oropharyngeal candidiasis (OPC) in head-and-neck cancer patients, undergoing radiotherapy, before and 2 weeks after radiation. Materials and Methods: In this quasi-experimental study, head-and-neck cancer patients undergoing radiotherapy (up to 6000 cGy) were recruited. Samples were taken before and 2 weeks after radiation therapy (RT). CC was assigned using Sabouraud dextrose agar culture medium and morphological studies were performed to confirm OPC. For identification, polymerase chain reaction-restriction fragment length polymorphism was performed. Data were analyzed using Chi-square-test and kappa coefficient. P < 0.05 was considered statistically significant. Results: Twenty-one of 33 patients were Candida positive. The detected fungal species included Candida albicans (60%), Candida tropicalis (22%), Candida glabrata (9%), and other species (9%). Following RT, OPC and CC changed significantly (P = 0.003 and P = 0.001, respectively), whereas ST did not significantly change (P = 0.081). Two new species (Candida krusei and Candida parapsilosis) were detected after the intervention. The OPC, CC, and ST changes after RT were not significantly related to malignancy site or radiation dose (P > 0.05). Conclusion: The present study showed that OPC, CC, and ST were not related to the malignancy site. Following RT, OPC and CC changed significantly, while ST showed no significant change. The radiation dose and malignancy site had no effects on the OPC, CC, or ST alterations following RT.

Comparison of the antifungal effect of voriconazole and fluconazole on oral candidiasis before and during radiotherapy.

Background: Head-and-neck radiotherapy can change oral Candida species and cause candidiasis resistance to common antifungals by making the changes to the oral cavity environment. Voriconazole is a synthetic azole with extensive antifungal activity. The current study aimed at comparing the antifungal activity of fluconazole and voriconazole on Candida species isolated from the oral cavity of patients undergoing head-and-neck radiotherapy. Materials and Methods: The present in vitro study was performed on samples isolated from patients undergoing head-and-neck radiotherapy, before and during radiotherapy. After the identification of the species, the antifungal effect of fluconazole and voriconazole was determined by the microdilution method, and the minimum inhibitory concentration (MIC), the minimum fungicidal concentration, and the antifungal susceptibility of the isolated strains were also measured. The data were analyzed by the Chi-squared and then two-sided Fisher's exact tests. P < 0.05 was considered statistically significant. Results: The study findings showed no significant difference in the susceptibility of Candida albicans to voriconazole and fluconazole before and during radiotherapy. Before radiotherapy, both voriconazole and fluconazole had similar effects on Candida tropicalis, but after radiotherapy, voriconazole was less effective. However, both before and during radiotherapy, fluconazole had a greater antifungal effect than voriconazole on Candida glabrata strains. The MICs of voriconazole and fluconazole for both Candida parapsilosis and Candida krusei isolates were within the susceptible or dose-dependent range. Conclusion: The current study results showed that voriconazole was not more effective than fluconazole in the treatment of oral candidiasis in patients undergoing head-and-neck radiotherapy.