[Candida urinary tract infection with special reference to ascending pyelonephritis]

Area of Science:

• Mycology
• Infectious Diseases
• Urology

Background:

• Candida urinary tract infections (UTIs) are a growing concern, particularly in patients with underlying urinary tract conditions.
• Candida albicans is the most frequently isolated Candida species from clinical urine samples.
• Limited understanding exists regarding the specific pathogenesis of ascending Candida pyelonephritis.

Purpose of the Study:

• To investigate the clinical and experimental pathogenesis of Candida UTIs.
• To compare the susceptibility of different Candida albicans serotypes to 5-fluorocytosine.
• To establish an experimental model for ascending pyelonephritis in rats.

Main Methods:

• Clinical isolates of Candida species were collected from Japan and the United States.
• Susceptibility testing of Candida albicans serotypes A and B to 5-fluorocytosine was performed.
• An experimental model of ascending pyelonephritis was established in female rats using Candida albicans, with immunosuppression (cyclophosphamide) or ureteral obstruction.

Main Results:

• Candida albicans was the predominant species isolated from candiduria patients.
• Candida albicans serotype B exhibited significantly lower susceptibility to 5-fluorocytosine compared to serotype A.
• Experimental pyelonephritis occurred in approximately 80% of immunosuppressed rats and over 70% of rats with ureteral obstruction, with a significant correlation between renal fungal load and pyelonephritis severity.

Conclusions:

• Underlying urinary tract conditions and prior antimicrobial use are common in patients with candiduria.
• Candida albicans serotype B may pose a challenge for 5-fluorocytosine treatment.
• The experimental rat model effectively replicates ascending Candida pyelonephritis, demonstrating a link between fungal burden and renal pathology.