The unique Efg1 fungal virulence regulon in the catheterized bladder environment

Area of Science:

• Mycology
• Infectious Diseases
• Medical Microbiology

Background:

• Urinary catheterization is a common medical procedure leading to significant nosocomial infections.
• Catheter-associated urinary tract infections (CAUTIs), often caused by *Candida albicans*, can lead to severe complications like sepsis and death.
• The specific mechanisms of *Candida albicans* pathogenesis in the urinary tract, particularly the role of the Efg1 transcription factor, are not well understood.

Purpose of the Study:

• To identify and validate the *EFG1* regulon active during conditions mimicking the human catheterized bladder.
• To understand the tissue-specific virulence factors of *Candida albicans* in CAUTI.
• To provide a roadmap for developing targeted therapies against CAUTI.

Main Methods:

• Transcriptional profiling of *C. albicans* under conditions simulating a catheterized bladder.
• Analysis of gene expression from catheters retrieved from patients with *C. albicans* infection.
• In vitro validation of gene function in human urine and in vivo testing using a CAUTI mouse model.

Main Results:

• The study identified a urine-specific *EFG1* regulon in *C. albicans* that is conserved in clinical samples.
• Efg1-dependent genes were significantly upregulated during active human CAUTI.
• Two key Efg1-regulated genes, *ECE1* and *EED1*, were validated as important contributors to *C. albicans* infection in vitro and in vivo.

Conclusions:

• The Efg1 regulon plays a critical role in *Candida albicans* pathogenesis within the catheterized bladder environment.
• Understanding these specific virulence factors is essential for developing novel anti-fungal strategies.
• Targeting the Efg1 regulon, including *ECE1* and *EED1*, presents a promising therapeutic avenue for combating life-threatening CAUTIs.