Biofilm formation of Candida isolates from xerostomic post-radiotherapy head and neck cancer patients.

Abstract

Oral candidiasis is a common problem in post-radiation head and neck cancer (HNC) patients. While biofilm formation is a crucial virulence factor for Candida colonization, existing information on biofilm formation capability of Candida in cancer patients is scarce. ObjectiveTo evaluate biofilm formation capability of Candida spp. colonized in xerostomic post-radiotherapy HNC patients. DesignCandida albicans and non-albicans Candida species were previously isolated from xerostomic post-radiation cancer patients and healthy individuals. Biofilm mass and biofilm metabolic activity were investigated by crystal violet and MTT assays, respectively. Their relationship with clinical parameters was analyzed using Mann-Whitney U and Chi-square tests. ResultsA total of 109 and 45 Candida isolates from 64 cancer patients and 34 controls, respectively, were evaluated. Both biofilm mass and metabolic activity of Candida isolates from cancer patients were higher than those from controls. The between-group differences were statistically significant in C. albicans (p < 0.001) for biofilm mass, and in C. tropicalis (p = 0.01) for biofilm metabolic activity. Overall, C. tropicalis was the best biofilm producers in both groups. Additionally, we found that higher biofilm formation among C. albicans was associated with low saliva buffering capacity. ConclusionsC. albicans and C. tropicalis isolated from xerostomic post-radiation cancer patients had higher biofilm formation capability than those from healthy individuals. Our findings suggest that, in addition to compromised host factors, higher biofilm formation capability may also contribute to the pathogenesis of oral candidiasis in HNC patients. This novel information potentially adds to proper management for these patients.