Fungal urinary tract infections are uncommon in small animals. Infections localized to the urinary tract are primarily due to Candida spp, with C albicans as the most common isolate; however, others (eg, Aspergillus spp, Cryptococcus neoformans, Rhodotorula mucilaginosa, and Trichosporon beigelii) have been reported. The urinary tract may also be involved in a systemic fungal infection. Some patients may have a bacterial coinfection.
Candida spp are commensal organisms of the genital mucosa. Candidal urinary tract infections are usually associated with a predisposing factor, such as previous antibacterial therapy, immunosuppression, or lower urinary tract disease or surgery; infections may also be urinary catheter–associated. Diabetes mellitus and neoplasia are reported comorbidities.
Clinical signs are similar to those of bacterial cystitis. Organisms (3- to 6-mm ovoid yeasts or pseudohyphae) are often identified on urine sediment examination; however, a definitive diagnosis should be made by identification of the fungal organism through urine culture.
Susceptibility testing is recommended to help guide treatment, but empirical therapy with fluconazole is reasonable because most C albicans isolates are susceptible. The most appropriate duration of therapy for dogs and cats is unknown, but most courses for small animals are prolonged (eg, 4–6 weeks) compared to similar treatment in humans.
