Urinary tract infections are occasionally caused by Candida albicans or other Candida species yeasts. If yeast is suspected as the cause, the urine culture will grow on special agar for yeast, appear as large, oval purple Gram-positive cells in the Gram stain, which may be budding and/or producing pseudohyphae, will be catalase positive, and if it is C. albicans, will be germ tube positive.
This is what the Microbiologist will see on the wet mount performed directly on the urine culture: large, oval budding yeast cells with pseudohyphae
These are Gram-stained yeast cells
If yeast is seen in the wet mount and Gram stain, the urine culture yeast suspect will be subcultured to Sabouraud agar and sealed. If there is growth, it will be tested for germ tube production, and biochemical testing will also be performed by the Mycology Dept. (part of Microbiology).
A positive germ tube test, seen above, after 2-3 hours of incubation, is usually indicative of C. albicans yeast.