Sensitivity and lower protease activity of Candida albicans species isolated from Egyptian cancer patients after exposure to cytotoxic and/or radiotherapy treatment

Oropharyngeal candidiasis is a common disease among cancer patients receiving chemo or radiotherapy which precede systemic candidemia, a life threatening infection. This study investigated the diversity and prevalence of different Candida species among Egyptian cancer patients, evaluated the sensitivity of Candida albicans to the frequently administered antifungal therapies and the effect of different radio and chemotherapeutic agents on its virulence. A total of 119 Candida spp. isolates were identified out of 399 clinical samples, of which 72 isolates were C. albicans, 15 were Candida tropicalis, 22 were Candida krusei, and 10 were Candida glabrata. 98.6% of the C. albicans isolates were sensitive to fluconazole; on the other hand, only 8.3% out of the tested isolates were sensitive to amphotericin B. No significant differences were observed in the ability of biofilm formation among C. albicans isolates exposed to chemo, radio or both therapies when compared with standard C. albicans ATCC 60193. Surprisingly, the protease activities in isolates obtained from cancer patients were significantly lower than that of the reference strain after exposure to chemo, radio or both therapies. Thus, it is concluded that radio and chemotherapies may not be in some cases a predisposing factor for the virulence of C. albicans strains.   Key words: Candidiasis, antifungal agents, virulence, radio and chemotherapy.