Which organism is typically seen in thrush in patients with AIDS?

The organism most commonly associated with thrush in patients with AIDS is Candida albicans. This yeast is part of the normal flora of the oral cavity and can overgrow under conditions such as immunosuppression, which is prevalent in individuals with AIDS. Thrush, or oral candidiasis, manifests as white patches on the mucous membranes of the mouth, and it is characterized by discomfort and difficulty swallowing in some cases.

While Candida glabrata, Candida dubliniensis, and Candida tropicalis can also cause infections, they are less frequently implicated in cases of oral thrush compared to Candida albicans. Candida glabrata tends to be more resistant to antifungal treatments and is associated with more systemic infections rather than localized infections like thrush. Candida dubliniensis, while capable of causing similar infections, is less commonly observed in the general population. Candida tropicalis, though it can cause candidiasis, is generally seen in more systemic infections.

Thus, the preeminent role of Candida albicans in oral thrush among immunocompromised patients, particularly those with AIDS, makes it the correct answer in this context.