AFM-IR Insights Into Cell Wall Remodeling and Protein Reorganization in Candida auris Versus Candida albicans

Candida auris is an emerging multidrug-resistant pathogen that poses a serious threat to public health, while Candida albicans is a well-studied commensal yeast. Investigating the structural and biochemical basis of C. auris persistence and drug resistance requires approaches capable of resolving both global and local cellular features. Here, we applied Fourier-transform infrared spectroscopy in combination with atomic force microscopy-infrared spectroscopy measurements to examine fungal cells at multiple scales, from colony-level biochemical composition to nanoscale organization within single cells. Ethanol fixation was implemented to safely handle C. auris, and its effects were first assessed in C. albicans. While fixation induced measurable modifications in lipids, glucans, and protein secondary structures, cell morphology was maintained, and dehydration improved AFM-IR reproducibility by reducing topographical artifacts. This validation confirmed that fixed cells can serve as reliable models for nanoscale spectroscopic analysis of pathogenic fungi. Comparison of fixed C. albicans and C. auris revealed striking species-specific differences. C. auris exhibited a more robust and heterogeneous polysaccharide network, including enriched mannan and β-1,3-glucan content, higher lipid levels with longer chains, and distinctive protein secondary structure features at the nanoscale, such as increased antiparallel β-sheets. These structural characteristics likely contribute to its environmental resilience, virulence, and multidrug resistance. Overall, this study introduces a multiscale spectroscopic platform that captures both global and nanoscale biochemical features of fungal cells, providing unique insights into C. auris biology and offering a foundation for future studies on antifungal responses and pathogen diagnostics.