Fungal infection causing urinary tract ulcers

Fungal urinary tract infections (UTIs) are uncommon but clinically significant, particularly in immunocompromised individuals, patients with prolonged indwelling urinary catheters, those receiving broad-spectrum antibiotics or systemic corticosteroids, and individuals with uncontrolled diabetes mellitus. While most UTIs are bacterial in origin, Candida species—most frequently Candida albicans, followed by C. glabrata and C. tropicalis—account for the vast majority of fungal UTIs. These infections can manifest as asymptomatic candiduria, cystitis, or, in more severe cases, upper urinary tract involvement such as pyelonephritis or fungal ball formation (mycetoma).

Urinary tract ulceration associated with fungal infection is rare but may occur in the context of invasive candidiasis or chronic, untreated fungal cystitis. Ulcerative lesions typically arise in the bladder mucosa and may be identified via cystoscopy as discrete, erythematous, sometimes necrotic or friable areas—often accompanied by pseudomembranous exudate or fungal plaques. Histopathologic examination reveals fungal hyphae and/or yeast forms invading the urothelium, with associated acute and chronic inflammatory infiltrates, epithelial erosion, and ulceration. Risk factors for invasive disease include urinary obstruction, renal transplantation, neutropenia, and prolonged antimicrobial exposure.

Diagnosis requires careful interpretation of urine culture: isolation of Candida from a clean-catch or catheterized specimen does not always indicate true infection—especially if colony counts are low (<10³–10⁴ CFU/mL) or if the patient is asymptomatic. Clinical correlation, imaging (e.g., renal ultrasound or CT to assess for obstruction or fungal balls), and cystoscopic evaluation with biopsy are essential when ulceration or invasive disease is suspected. Treatment depends on severity and immune status: fluconazole remains first-line for susceptible isolates in non-neutropenic patients; echinocandins (e.g., caspofungin, micafungin) or amphotericin B are preferred for neutropenic patients, fluconazole-resistant strains, or documented upper tract invasion. Removal of urinary catheters and correction of underlying predisposing conditions are critical adjunctive measures.