What is Candiduria in ICU Patients?
Candiduria is the presence of Candida species (yeast) in the urine, which in ICU patients most commonly represents benign colonization rather than true infection, particularly in those with indwelling urinary catheters. 1
Definition and Clinical Significance
Candiduria refers to the isolation of Candida species from urine samples. 2 In the ICU setting, this finding presents a diagnostic challenge because:
- Candida species are now among the most frequently isolated organisms from urine in surgical ICUs 1
- The majority of cases represent colonization as a benign event rather than true infection 1, 3
- Distinguishing infection from colonization is the greatest obstacle to diagnosis 1
Key Epidemiological Features in ICU Patients
The prevalence and characteristics of candiduria in critically ill patients include:
- Among ICU patients, candiduria occurs in approximately 7.8% (162 of 2086 patients in one prospective study) 4
- C. albicans remains the predominant species (52.2%), followed by C. glabrata (21.8%) and C. tropicalis (14.3%) 4
- Only 31.4% of ICU patients with candiduria are symptomatic 4
Relationship to Invasive Disease
Understanding the connection between candiduria and systemic infection is critical:
- In non-catheterized patients, candiduria is strongly suggestive of renal involvement in disseminated candidiasis 1
- However, in catheterized ICU patients (the majority), candiduria is no more significant an indicator of invasive disease than isolation from any other single colonization site 1
- Up to 50% of patients with disseminated candidiasis do not have candiduria, making it an unreliable marker 1
- Candiduria rarely progresses to candidemia (<5% of cases), even in high-risk populations 5
Clinical Manifestations
Candiduria can represent several distinct clinical entities:
- Asymptomatic colonization (most common in catheterized patients) 3
- Symptomatic cystitis 5, 2
- Pyelonephritis 5, 2
- Hematogenous seeding from candidemia (Candida can reach the urinary tract via bloodstream) 2
- Ascending infection (retrograde route via the urethra) 2
Major Risk Factors in ICU Patients
Multiple risk factors converge in the ICU setting to increase candiduria risk:
- Urinary catheterization (most significant risk factor) 6, 7
- Broad-spectrum antibiotic use 6, 7
- Advanced age and female sex 8, 7
- Diabetes mellitus 8, 2, 7
- Severity of illness (higher APACHE II scores) 9
- Urinary tract obstruction 2, 7
- Previous surgical procedures 7
Diagnostic Considerations
A single colony of Candida from a sterile site (blood, CSF) must be regarded as significant, but quantitative cutoff values for diagnosis from non-sterile sites like urine are much less well established than for bacterial infections. 1
Prognostic Implications
- Candiduria is associated with a mortality rate of 25.3% in ICU patients, but death is not related to Candida infection itself 4
- Candiduria serves as a marker for greater mortality, but treatment of asymptomatic candiduria does not change mortality rates 8
- In patients with ongoing sepsis and high APACHE scores, candiduria may be an early indicator of systemic infection 9
Common Pitfall
The critical error is treating asymptomatic candiduria in catheterized ICU patients, which occurs in approximately 31.5% of cases despite guideline recommendations against this practice. 4 This inappropriate treatment promotes antifungal resistance without improving outcomes. 3