Dangerous fungi are adopting a new survival strategy
09/22/2026A research team led by scientists from Würzburg has shown that resistant strains of the fungus Candida parapsilosis break down their protective coating, thereby evading the immune system and spreading more easily.
Candida parapsilosis is a yeast fungus that commonly lives on human skin. It does not usually cause any problems in healthy people. It becomes particularly dangerous for people whose immune systems are weakened or whose natural protective barriers have been compromised by medical procedures.
If the fungus enters the bloodstream – for example, via a catheter or a skin wound – it can cause serious infections. Furthermore, it can be transmitted from person to person . In recent years, there have been repeated outbreaks in hospitals worldwide. During these outbreaks, strains of the fungus that are resistant to the commonly used antifungal drug fluconazole have spread.
A new approach: less biofilm, less surface area for infection
Until now, pronounced biofilm formation was considered a key factor in the resilience of such pathogens: fungi and bacteria can build a cement-like protective shield around themselves. This helps them to thrive in their environment and withstand attacks from antibiotics, antifungal drugs or the immune system’s white blood cells.
Dr Amir Arastehfar now reports a surprising twist: “Instead of building even stronger fortresses, the strains causing the outbreaks are taking a risky gamble by reducing their protective biofilm. In return, they gain two enormous advantages: human immune cells cannot recognise them, and they can multiply much more rapidly under extreme stress.”
The junior research group leader has developed these new findings on fluconazole-resistant strains of Candida parapsilosis in collaboration with an international research team and published them in the journal PLoS Biology . Amir Arastehfar is part of Professor Jürgen Löffler’s ‘Invasive Fungal Infections’ research group at Würzburg University Hospital (UKW).
Adaptation as the key to success
By analysing genomic data from hospitals in several countries, the researchers have found that this shift in biofilm strategy is occurring independently across the globe. “Frequent transmission from one host to another effectively trains the fungus to swap an ancient survival trait for a modern one. This enables it to evade our immune system and persist in healthcare settings,” says Amir Arastehfar.
The findings therefore change our understanding of why resistant strains of Candida parapsilosis are able to persist in hospitals over the long term.
Analysing the fungus’s global whole genome
It may not be solely resistance to drugs or the ability to survive in a hospital environment that is crucial. Adaptation to the human immune system also appears to play an important role.
Amir Arastehfar: “We therefore intend to carefully analyse the global whole genome of Candida parapsilosis to find out which genetic traits give the fungus the ability to hide from immune cells and remain in the hospital environment permanently.”
Researchers from the University of Würzburg’s Institute of Hygiene and Microbiology, led by Professor Oliver Kurzai, as well as PhD students Tobias Köhler and Gabriel Braune , were involved in the study. The Interdisciplinary Centre for Clinical Research provided financial support for Amir Arastehfar’s research as part of the WüConnect programme.
Publication
Outbreaks of fluconazole-resistant Candida parapsilosis are driven by low-biofilm-producing isolates that emerge under host selection. PLoS Biology, 1 September 2026, Open Access: https://doi.org/10.1371/journal.pbio.3003973
