Acid-fast diarrhea in an AIDS patient is commonly due to which pathogen?

In the context of an AIDS patient presenting with diarrhea, cryptosporidiosis is a significant concern due to the immunocompromised status associated with HIV/AIDS. Cryptosporidium is a protozoan parasite that can lead to profuse, watery diarrhea, particularly in individuals with CD4 counts below 200 cells/mm³. Notably, the oocysts of Cryptosporidium are acid-fast, which allows them to be identified using special staining techniques.

While Mycobacterium tuberculosis can also be identified as acid-fast bacilli, it is more commonly associated with pulmonary disease in AIDS patients rather than causing diarrhea. On the other hand, Escherichia coli and Salmonella are less likely to be associated with the classic acid-fast appearance and are not typically considered the primary pathogens responsible for diarrhea in this population. Therefore, in an AIDS patient experiencing diarrhea with an acid-fast appearance, Cryptosporidium is the pathogen that is most likely responsible.