SIP-SRS Imaging of Cell Wall Synthesis Identifies a Synergy between Micafungin and Amphotericin B

Candida species causes life-threatening infections in immunocompromised individuals and presents a formidable challenge in clinical practice. This challenge is exacerbated by the growing prevalence of drug resistance, particularly against the last resort antifungals such as amphotericin B (AmB). The fungal cell wall, known for its dynamic reorganization in response to growth demands and host threats, are recognized as a key drug target. In this study, stable isotope probe-assisted SRS microscopy (SIP-SRS) is harnessed to directly visualize and interrogate the dynamics of fungal cell wall synthesis under various antifungal treatments. A striking observation is the thickening of the cell wall in newly synthesized daughter cells under AmB treatment. Based on this finding, a synergistic inhibition of fungal growth is demonstrated by AmB and micafungin, an antifungal agent targeting cell wall synthesis. These results not only advance the understanding of fungal physiology at the molecular level but also open promising avenues for combating drug-resistant fungal infections.