Echinocandin Efficacy and Mechanisms in Fungal Infections

Echinocandins are a class of semisynthetic cyclic lipopeptide antifungals that target the fungal cell wall by inhibiting β-1,3-glucan synthase, an enzyme essential for the synthesis of the primary structural polysaccharide in many pathogenic yeasts and moulds. Clinically, they display fungicidal activity against most Candida species and fungistatic effects against Aspergillus, with a high margin of safety in human hosts. Despite their efficacy in bloodstream and deep-seated infections, challenges remain in oral delivery due to poor bioavailability, and in the emergence of therapeutic failure driven by both genetic resistance—often via hot-spot mutations in FKS genes—and adaptive tolerance mechanisms. Fungal cells can mount protective responses such as upregulated chitin synthesis, activation of calcineurin-dependent signalling cascades, and modifications of membrane lipids that diminish drug binding. A notable in vitro phenomenon, the paradoxical effect, describes resumed growth at elevated drug concentrations and reflects complex regulatory networks. Integrating echinocandins with inhibitors of compensatory pathways or exploiting newly identified fungal signalling mediators holds promise for overcoming tolerance and expanding the antifungal armamentarium.

Research from Nature Portfolio

Recent studies have revealed an endogenous oxylipin-driven tolerance programme in Aspergillus fumigatus. Treatment with echinocandins triggers synthesis of the oxygenated fatty acid 5,8-diHODE via a fungal oxygenase, which in turn activates the transcription factor ZfpA. This positive feedback loop reinforces cell-wall integrity at hyphal tips, reducing echinocandin-induced lysis and enabling survival across diverse pathogenic isolates. The discovery of this conserved oxylipin–ZfpA relay unveils a natural tolerance mechanism likely evolved in response to environmental echinocandin-producing organisms and suggests new targets to potentiate existing therapies.

Echinocandin Efficacy and Mechanisms in Fungal Infections publication trend

The graph below shows the total number of articles in echinocandin efficacy and mechanisms in fungal infections across all publications each year (not limited to Nature Index journals).

Technical terms

Echinocandin: A semisynthetic cyclic lipopeptide antifungal that inhibits β-1,3-glucan synthase, disrupting fungal cell-wall integrity.

β-1,3-Glucan synthase: A membrane-bound enzyme complex that polymerises glucose into β-1,3-glucan chains, a critical component of the fungal cell wall.

Oxylipin: An oxygenated fatty acid derivative acting as a signalling molecule in fungi, modulating growth and stress responses.

Paradoxical effect: The unexpected resumption of fungal growth at high echinocandin concentrations despite susceptibility at lower doses.

Bioavailability: The fraction of an administered drug that reaches the systemic circulation and is available to exert its therapeutic effect.

Hyphae: The thread-like filamentous structures constituting the vegetative growth form of many fungi.

Minimum inhibitory concentration (MIC): The lowest concentration of an antifungal agent that prevents visible growth of a microorganism in vitro.

References

1. An oxylipin signal confers protection against antifungal echinocandins in pathogenic aspergilli. Nature Communications (2024).
2. Rapid automated antifungal susceptibility testing system for yeasts based on growth characteristics. Frontiers in Cellular and Infection Microbiology (2023).
3. Antifungal effects of echinocandins diminish when exposed to intestinal lumen contents: a finding with potentially significant clinical implications. Frontiers in Pharmacology (2024).
4. Stress-Induced Changes in the Lipid Microenvironment of β-(1,3)-d-Glucan Synthase Cause Clinically Important Echinocandin Resistance in Aspergillus fumigatus. mBio (2019).
5. Emergence of Echinocandin Resistance Due to a Point Mutation in the fks1 Gene of Aspergillus fumigatus in a Patient with Chronic Pulmonary Aspergillosis. Antimicrobial Agents and Chemotherapy (2017).