A patient on prolonged broad-spectrum antibiotics develops thrush. Candida albicans is isolated. The virulence factor that allows C. albicans to switch from yeast to hyphal (filamentous) form and invade tissue is:
- A Yeast-to-hyphae transition enabling tissue invasion and resistance to phagocytosis ✓
- B Secreted aspartyl proteinases (SAPs) only
- C Capsule formation blocking complement deposition
- D Thermotolerance up to 45°C enabling survival
Explanation
Candida albicans possesses a unique dimorphic capacity to transition from yeast to hyphae (germ tubes/pseudohyphae/true hyphae), triggered by environmental signals including CO2, serum, body temperature, neutral pH, and N-acetylglucosamine. The hyphal form is the invasive, tissue-penetrating phenotype; hyphae are less susceptible to phagocytosis (too large to engulf by macrophages), penetrate mucosal barriers, and express higher levels of virulence factors including Hwp1 (candidal adhesin), Als3 (invasion mediator), and SAPs. SAPs are important but not the primary determinant of tissue invasion. Capsule formation is a Cryptococcus feature, not C. albicans.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.