Relying on a urinary catheter is a standard part of medical care for hundreds of thousands of patients each year. Unfortunately, the device carries the risk of catheter-associated urinary infections (CAUTIs), where bacteria are widely recognized as the primary cause.
And yet, many patients face a growing threat from another pathogen: a fungus, Candida albicans.
by University of Notre Dame associate professors of biological sciences, and , shows how the fungus works in the bladder, potentially changing the way doctors treat and diagnose CAUTIs.
Their work is a continuation of foundational work the research team previously published. They mapped a critical protein called Efg1, which serves as a 鈥渕aster switch鈥� in聽C. albicans. Without this protein, the fungus cannot cause disease in a catheterized bladder. However, Flores-Mireles and Santiago-Tirado did not know which specific target genes Efg1 commanded inside a catheterized bladder.
鈥淭his protein has been really well described in other infections, but not in the bladder,鈥� Flores-Mireles said.
The research team sequenced the genetic activity of Candida strains, identifying 75 target genes that are turned on in the bladder. Twenty-six had never been characterized before, proving how unique the bladder environment is. To verify their laboratory findings, Flores-Mireles and Santiago-Tirado, along with their doctoral student and first author, Alyssa La Bella, evaluated urinary catheters collected from patients with C. albicans by analyzing fungal RNA directly from those devices. The fungal gene network they saw in the laboratory was nearly identical to the one they detected in patient samples.
鈥淲hen we got the samples from humans, and saw the exact same results, we knew this was 鈥榬eal,鈥欌�� Flores-Mireles said.
Physicians often characterize fungus found on catheters as potential contamination rather than part of the active infection within the bladder, Santiago-Tirado said. This is because current diagnostic tools are designed to detect 鈥渟wimming鈥� bacteria in urine samples, rather than biofilms attached to catheters.
鈥淔or us to be able to get these catheters and show that, yes, this factor is critical, that this fungus is a colonizer, and not contamination, is important,鈥� Flores-Mireles said. 鈥淚t鈥檚 actually a virulent process.鈥�
Their study also described how C. albicans behaves when sharing space with bacteria on a catheter. When researchers examined catheters containing both Candida and E. coli, the virulence of the Candida decreased because it is often killed by the bacteria.
鈥淧eople will study these infections as monomicrobial, as like, pure infection from one pathogen,鈥� Santiago-Tirado said. 鈥淏ut now we realize that in reality, in hospitals, in real life, almost all of the infections are polymicrobial, so people are starting to look more carefully at interactions between microbes and how they might have positive or negative contributions to the person鈥檚 symptoms.鈥�
In addition to the lead team at the University of Notre Dame, collaborators contributed from the University of Guelph, Washington University 91视频 of Medicine in St. Louis, and the Leibniz Institute for Natural Product Research and Infection Biology (Hans Kn枚ll Institute). The study was supported primarily by funding from the National Institutes of Health.
Contact: Brandi Wampler, associate director of media relations, 574-631-2632, brandiwampler@nd.edu
Originally published by at on August 27, 2026.