Susceptibility and virulent attributes of Candida from Hong Kong and Finland

Abstract

Objectives: Candida is a commensal fungus that resides in at least 50% of human oral cavities. Oral and systemic infection caused by Candida has dramatically increased in the last decade due to growing number of compromised populations. In the present study, we evaluated the antifungal susceptibility profiles and virulent attributes of Candida oral and blood stream isolates derived from Hong Kong and Finland, information which are vital for devising empirical clinical strategies. Methods: Susceptibility testing of Candida isolates was performed against a wide range of antifungals including fluconazole, itraconazole, voriconazole, ketoconazole, 5-fluorocytosine, amphotericin-B and caspofungin according to the CLSI M-44A disc diffusion assay and CLSI M-27A broth microdilution assay. Secreted aspartyl proteinases (SAPs) levels of Candida isolates were determined by bovine serum albumin assay and haemolytic activity was evaluated using Sabouraud dextrose agar supplemented with 3% glucose and fresh sheep blood. Results: All blood stream isolates derived from Hong Kong were susceptible to all the antifungals tested whilst some isolates from Finland were resistant to azoles and caspofungin. C. albicans, C. glabrata and C. tropicalis showed higher haemolytic activity whereas C. parapsilosis and C. guilliermondii were non-haemolytic in general. Proteinase activity of the Finland C. albicans isolates was significantly higher than the Hong Kong isolates. Conclusion: Our data provide a glimpse of the possible evolutionary changes in pathogenic potential of Candida that may be occurring in different regions of the world. Therefore, continuous surveillance and availability of local data should be taken into consideration when treating Candida infections (RGC-Grant HKU-7624/06M).