True statements regarding diarrhea in HIV infection include all of the following except:

Diarrhea is a common complaint of HIV - infected patients. A wide variety of pathogens have been described, but frequently no specific pathogen can be found. Routine cultures, ova and parasite examination, and acidfast stains for Cryptosporidium should be obtained, If initial specimens are negative, repeating ova and parasite and Cryptosporidia studies may be useful. Salmonella is more difficult to treat in HIV -infected patients. Enteritis may be accompanied by bacteremia, which may be difficult to eradicate and may require chronic suppressive therapy. The most common parasites described in conjunction with diarrhea and HIV infection are Giardia lamblia, Entamoeba histolytica, and Cryptosporidium. Effective therapy is available for Giardia and Entamoeba, but no treatment has proven effective for Cryptosporidium. Isospora belli can cause watery diarrhea, which resolves with trimethoprimlsulfamethoxazole therapy. Diarrhea secondary to mycobacterium avium complex does not respond well to directed therapy.