A 27-year-old woman, HIV positive, has 6 months of nonbloody diarrhea now with bloody diarrhea. She has a high fever and a rigid abdomen. She ends up with an ileostomy for a perforated cecum and the pathology report shows nuclear inclusion bodies in colon. Most likely organism?
A) Cryptosporidium parvum
B) Entamoeba histolytica
C) Cytomegalovirus
D) Mycobacterium avium-intracellulare