Caspofungin at sub-inhibitory concentration promotes the formation of Candida albicans persister cells.

Aims: Low caspofungin exposure is frequently encountered in patients with invasive candidiasis caused by Candida albicans. This study aimed to investigate the effects of caspofungin on C. albicans at sub-inhibitory concentrations.

Methods And Results: First, a comparative transcriptomics analysis was performed on C. albicans receiving caspofungin at sub-minimum inhibitory concentrations (sub-MICs). The results showed that caspofungin significantly changed the mRNA expression profile in DAY185, with DE-mRNAs enriched in the functions of cell wall biosynthesis, metabolism, etc. Subsequently, cellular fitness, cell aggregation, energy metabolism activity and the proportion of persister cells of C. albicans were quantitatively and/or qualitatively assessed after sub-MIC caspofungin exposure. No significant changes in cell fitness and aggregation formation were observed during treatment of C. albicans with sub-MIC caspofungin. In C. albicans aggregation treated with sub-MIC caspofungin, we observed a decrease in respiratory metabolism and an increase in persister cells; this effect was more pronounced in als1ΔΔ than in DAY185.

Conclusions: Pre-exposure to sub-MIC caspofungin suppresses C. albicans respiratory metabolism and promotes persister cell development.

Significance And Impact Of The Study: Caspofungin should be used with caution in patients with C. albicans infections, as anti-infection therapy may fail due to persister cells.