Oral candidiasis (thrush) is an opportunistic infection most commonly caused by which eukaryotic microorganism?

• A. Cryptococcus neoformans
• B. Plasmodium falciparum
• C. Aspergillus fumigatus
• D. Candida albicans

Answer: (D)

Verified step by step guidance

1. Understand that oral candidiasis, also known as thrush, is an opportunistic infection affecting the mucous membranes of the mouth.
2. Recognize that the infection is caused by a eukaryotic microorganism, specifically a type of fungus.
3. Review the options given: Cryptococcus neoformans (a yeast causing cryptococcosis), Plasmodium falciparum (a protozoan causing malaria), Aspergillus fumigatus (a mold causing aspergillosis), and Candida albicans (a yeast commonly found in the human microbiota).
4. Recall that Candida albicans is the most common cause of oral candidiasis because it is a commensal organism that can overgrow when the immune system is compromised or the normal flora is disrupted.
5. Conclude that among the options, Candida albicans is the eukaryotic microorganism most commonly responsible for oral candidiasis (thrush).