How should I treat a suspected Candida urinary tract infection (cystitis) in an otherwise healthy adult with uncomplicated disease?

Treatment of Suspected Candida Urinary Tract Infection (Cystitis) in Healthy Adults

For an otherwise healthy adult with suspected uncomplicated Candida cystitis, administer oral fluconazole 200 mg (approximately 3 mg/kg) once daily for 14 days; this is the only regimen validated by randomized controlled trial evidence and achieves high urinary concentrations that reliably eradicate the pathogen. 1

Initial Assessment: Symptomatic vs. Asymptomatic Disease

Before initiating therapy, distinguish whether the patient has true symptomatic infection or asymptomatic colonization:

• Symptomatic cystitis presents with dysuria, urinary frequency, urgency, or suprapubic discomfort—these patients require antifungal treatment. 1
• Asymptomatic candiduria in otherwise healthy adults almost always represents benign colonization and does not warrant antifungal therapy, as treatment does not reduce mortality or improve clinical outcomes. 1
• The presence of pyuria or colony counts cannot reliably distinguish infection from colonization, especially in catheterized patients—do not base treatment decisions on these parameters alone. 1

First-Line Pharmacologic Therapy

• Fluconazole 200 mg orally once daily for 14 days is the preferred regimen for fluconazole-susceptible Candida cystitis; this recommendation is based on the only randomized, double-blind, placebo-controlled trial demonstrating clinical efficacy. 1
• Fluconazole is favored because it attains exceptionally high concentrations of active drug in urine, ensuring effective pathogen eradication. 1, 2
• The 14-day duration is critical—do not discontinue prematurely based solely on symptom resolution, as this increases relapse risk. 3

Essential Non-Pharmacologic Management

• Immediately remove any indwelling urinary catheter if present; this single intervention clears candiduria in approximately 50% of cases without requiring antifungal medication. 1, 4
• Discontinue unnecessary broad-spectrum antibiotics, as these are a major predisposing factor for candiduria. 1
• Eliminate any urinary tract obstruction to facilitate infection clearance. 1

Management of Fluconazole-Resistant Species

If culture identifies Candida glabrata (often fluconazole-resistant) or Candida krusei (intrinsically fluconazole-resistant):

• Administer amphotericin B deoxycholate 0.3–0.6 mg/kg IV daily for 1–7 days, with or without oral flucytosine 25 mg/kg four times daily for 7–10 days. 1, 5
• Oral flucytosine monotherapy (25 mg/kg four times daily for 7–10 days) may be considered when amphotericin B is unsuitable, though this is a weaker recommendation. 1
• For refractory fluconazole-resistant cystitis, bladder irrigation with amphotericin B deoxycholate (50 mg/L sterile water daily for 5 days) can be employed, but relapse rates approach 80–90%. 1

Recognizing Upper Tract Involvement (Pyelonephritis)

If the patient develops flank pain, fever >38.3°C, or other systemic manifestations, suspect Candida pyelonephritis:

• Increase fluconazole dosing to 200–400 mg (3–6 mg/kg) orally once daily for 14 days; use the higher 400 mg dose when upper-tract involvement is confirmed. 1, 3
• Obtain renal or bladder imaging (ultrasound or CT) if symptoms persist beyond 48–72 hours to exclude obstruction, fungal balls, or perinephric abscesses. 1
• Presence of fungal balls or casts in the renal pelvis or bladder mandates surgical or endoscopic removal in addition to systemic antifungal therapy—antifungal agents alone are insufficient without drainage. 1

Critical Pitfalls to Avoid

• Do not use echinocandins (caspofungin, micafungin, anidulafungin) or newer azoles (voriconazole, posaconazole) for urinary Candida infections—these agents achieve inadequate urine concentrations and are ineffective for lower urinary tract infections. 1, 4, 2
• Do not use lipid formulations of amphotericin B for Candida urinary tract infections, as they do not attain adequate urinary levels. 1
• Do not treat asymptomatic candiduria in otherwise healthy individuals, including diabetic or elderly patients without additional high-risk features—this provides no clinical benefit and promotes unnecessary antifungal exposure and potential resistance development. 1, 4
• In male patients, do not automatically dismiss candiduria as simple colonization; anatomical factors (prostate, longer urethra) increase the likelihood of true infection, and evaluation for possible prostatitis is warranted if urinary symptoms develop. 1

Follow-Up and Recurrence

• For recurrent candiduria after appropriate treatment, evaluate for underlying urologic abnormalities such as strictures, stones, prostatic disease, or persistent obstruction. 1
• Candiduria progresses to candidemia in less than 5% of cases; it mainly serves as a marker of overall illness severity rather than a direct cause of morbidity. 1