Role of catalase overproduction in drug resistance and virulence in Candida albicans

Aim: To investigate the role of Cat1 overproduction in Candida albicans. Materials & methods: Strains overproducing the CAT1 gene were constructed. Results: Cells overproducing CAT1 were found to be more resistant to some oxidants and mammalian phagocytic cells. They also showed reduced intracellular reactive oxygen species generated by amphotericin B or ciclopirox olamine. CAT1 overproduction did not change the minimum inhibitory concentration of fungal cells to fungistatic or fungicidal azoles nor to amphotericin B although increased twofold the minimum inhibitory concentration to caspofungin. The role of Cat1 overproduction in virulence and colonization was also analyzed in mouse models. Conclusion: The overproduction of Cat1 protects against oxidants, phagocytes and certain antifungals at subinhibitory concentration but does not increase virulence in a systemic infection mouse model.