In a 59-year-old woman with persistent dysuria, pyuria and yeast on repeat urinalysis despite a 5‑day course of nitrofurantoin and fluconazole 150 mg, what is the next appropriate management step?

Management of Persistent Candiduria with Dysuria

This patient requires urine culture with fungal speciation and susceptibility testing, followed by fluconazole 200 mg daily for 2 weeks for presumed Candida cystitis. 1

Diagnostic Evaluation

The persistent pyuria and yeast cells on microscopy after inadequate initial therapy strongly suggest true Candida cystitis rather than simple colonization. 1 The key distinguishing features here are:

• Persistent dysuria (symptomatic infection, not asymptomatic candiduria) 1
• Persistent pyuria (1-2+ leukocytes across multiple urinalyses) 1
• Yeast cells on microscopy (not just culture contamination) 1

Obtain urine culture with fungal speciation immediately to identify the Candida species and determine fluconazole susceptibility, as this will guide definitive therapy. 1 This is critical because approximately 20% of urinary Candida isolates in adults are C. glabrata, which is frequently fluconazole-resistant. 1

Why Initial Therapy Failed

The single 150 mg dose of fluconazole was inadequate for Candida cystitis. 1 While 150 mg single-dose fluconazole is appropriate for vulvovaginal candidiasis, Candida cystitis requires fluconazole 200 mg daily for 2 weeks. 1 The initial treatment was essentially treating the wrong condition with the wrong duration.

Additionally, nitrofurantoin has no antifungal activity and was treating a presumed bacterial UTI that likely wasn't present. 1

Recommended Treatment Algorithm

For Fluconazole-Susceptible Species (Most C. albicans)

• Fluconazole 200 mg (3 mg/kg) orally daily for 2 weeks 1
• This is the first-line treatment and achieves high urinary concentrations as active drug 1

For Fluconazole-Resistant C. glabrata

If culture reveals C. glabrata with fluconazole resistance:

• Oral flucytosine 25 mg/kg four times daily for 7-10 days 1
• Alternative: Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1
• Bladder irrigation with amphotericin B may be considered but has high relapse rates 1

For C. krusei

• Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1

Critical Management Considerations

Address predisposing factors: 1

• Recent antibiotic use (nitrofurantoin) disrupts normal flora and promotes Candida overgrowth 1
• Evaluate for diabetes, immunosuppression, or urologic abnormalities 1
• Consider imaging (ultrasound or CT) if symptoms persist despite appropriate therapy to rule out fungus balls, obstruction, or structural abnormalities 1

Do not use echinocandins or other azoles: These achieve minimal urinary concentrations and are ineffective for Candida UTI. 1 Lipid formulations of amphotericin B similarly fail to achieve adequate urine levels. 1

Common Pitfalls to Avoid

1. Treating asymptomatic candiduria: If the patient were asymptomatic, observation alone would be appropriate after removing predisposing factors. 1 However, this patient has persistent dysuria, making treatment necessary.

2. Using single-dose fluconazole: This dose is only for vulvovaginal candidiasis, not urinary tract infection. 1

3. Assuming all Candida are fluconazole-susceptible: Always obtain speciation and susceptibilities, especially in a 59-year-old woman where C. glabrata prevalence is significant. 1

4. Repeating nitrofurantoin: This has no role in fungal infections. 1

Follow-Up

Post-treatment urinalysis is not routinely indicated if symptoms resolve. 1 However, if symptoms persist or recur within 2 weeks, repeat urine culture and consider:

• Treatment failure due to resistant organism 1
• Structural abnormality requiring imaging 1
• Fungus ball formation requiring surgical intervention 1