Antifungal susceptibility of non-albicans Candida species from blood samples

Globally, non-albicans Candida (NAC) species have emerged as a notable cause of both healthcare-associated and opportunistic infections. Compared with Candida albicans, NAC species are more likely to cause infections fraught with antifungal resistance issues and higher mortality rates. The objectives of this study were to identify the various Candida species causing candidaemia in a Malaysian general hospital and to ascertain their antifungal susceptibility profiles.

This 15-month cross-sectional study involved the peripheral blood of patients diagnosed with candidaemia. Conclusive species identification was achieved through matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) while antifungal susceptibility was performed using the colourimetric broth microdilution method.

A total of 118 non-duplicate Candida isolates were analysed during the study period. Out of this total, 47 (39.8%) were C. albicans, 25 (21.2%) were Candida parapsilosis complex, 24 (20.3%) were Candida tropicalis, 19 (16.1%) were Nakaseomyces glabratus and three (2.6%) were Pichia kudriavzevii. Collectively, the NAC species outnumbered C. albicans (60.2% vs. 39.8%). The overall minimal inhibitory concentration at which ≥90% of isolates were inhibited (MIC90) for NAC species was 32 µg/mL for fluconazole, 1 µg/mL for amphotericin B and between 1 to 2 µg/mL for the echinocandins.

Despite C. albicans being the single most frequently isolated species from patients with candidaemia, more than half of candidaemia cases in our centre were caused by NAC species. Generally, although these NAC species were not fluconazole-susceptible, amphotericin B and echinocandins may still be utilised against them.