Since the early 1980s, the prevalence of candiduria in hospitals has increased by 200% to 300% such that in a community hospital, 5% of urine cultures may yield Candida, and in tertiary care centers, Candida accounts for almost 10% of urinary isolates, including a quarter of Foley catheter-associated infections. Most positive Candida urine cultures are isolated or transient findings of little significance and represent colonization of catheters rather than true infection. Although less than 10% of candidemias are the consequence of candiduria, Candida urinary tract infections (UTIs) have emerged as important nosocomial infections.
Candida albicans is the most common species isolated from the urine, whereas non-albicans Candida species account for almost half the Candida urine isolates. Candida glabrata is responsible for 25% to 35% of infections.
Candiduria is rare in the absence of predisposing factors. Most infections are associated with use of Foley catheters, internal stents, percutaneous nephrostomy tubes, and age extremes of life. Diabetic patients, especially when their diabetes is poorly controlled, are particularly at risk primarily because of increased instrumentation, urinary stasis, and obstruction secondary to autonomic neuropathy. Concomitant bacteriuria is common and bacterial adherence to bladder epithelium may play a key role in the pathogenesis of Candida infection. Antimicrobials similarly play a critical role in that candiduria almost always emerges during or immediately after antibiotic therapy. Antibiotics, especially broad-spectrum agents, act by suppressing protective indigenous bacterial flora in the gastrointestinal (GI) tract and lower genital tract, facilitating Candida colonization of these sites with ready access to the urinary tract. Nosocomial candiduria is more common in intensive care unit (ICU)-based catheterized women with concomitant contributory vaginal Candida colonization. The pool of critically ill, immunosuppressed medical, and surgical patients has increased, and this increase, together with improved technology, provides an expanded population at risk of developing Candida infection.