A 34-year-old woman with poorly controlled type 2 diabetes (HbA1c 10.2%) presents with vulvovaginal pruritus and thick, white vaginal discharge for 2 weeks. On speculum examination, white plaques are visible on the vaginal wall. KOH mount of the discharge shows budding yeast cells and pseudohyphae. She has no fever. What is the most likely causative organism?

Explanation

## Diagnosis: Candida albicans Vulvovaginitis ### Clinical Presentation **Key Point:** Vulvovaginitis with thick white discharge, visible plaques, and KOH mount showing budding yeast + pseudohyphae is pathognomonic for *Candida albicans*. ### Why C. albicans is Most Likely | Feature | C. albicans | C. glabrata | C. auris | C. tropicalis | |---------|-------------|------------|---------|---------------| | **Pseudohyphae** | Yes (common) | No | No | Yes | | **Budding yeast** | Yes | Yes | Yes | Yes | | **Vulvovaginitis** | Most common (90%) | Rare | Rare | Rare | | **Hyperglycemia risk** | High | Moderate | Moderate | Moderate | | **Antifungal resistance** | Low | High (fluconazole) | Very high | Moderate | **High-Yield:** *Candida albicans* accounts for ~90% of vulvovaginal candidiasis cases. The presence of **pseudohyphae on KOH mount is the diagnostic hallmark**. ### Pathophysiology 1. Hyperglycemia impairs neutrophil function and T-cell immunity 2. High vaginal glucose concentration favors *C. albicans* growth 3. Disruption of normal lactobacillus flora allows overgrowth 4. Pseudohyphae invade epithelium → inflammation and symptoms **Clinical Pearl:** Poorly controlled diabetes is a major risk factor for recurrent vulvovaginal candidiasis. Glycemic control improves outcomes. ### Identification Features of C. albicans - **Germ tube test:** Positive (forms true hyphae at 37°C in serum) — gold standard for rapid identification - **Chlamydospore formation:** Terminal thick-walled spores on cornmeal agar - **Morphology:** Dimorphic — yeast at 25°C, hyphae at 37°C - **Culture:** Grows on Sabouraud dextrose agar (white/cream colonies) **Mnemonic:** **GERM** = **G**erm tube test, **E**ndotoxin-like (pseudohyphae), **R**ecurrent in diabetes, **M**ost common Candida ### Treatment - **First-line:** Topical azoles (miconazole, clotrimazole) or oral fluconazole 150 mg single dose - **Recurrent VVC:** Prophylactic fluconazole 150 mg weekly × 6 months - **Essential:** Glycemic control (HbA1c target <7%) [cite:Textbook of Microbiology by Ananthanarayan & Paniker 10e]