Clinical and microscopical features of small-intestinal microsporidiosis in patients with AIDS.

Intestinal microsporidiosis by Enterocytozoon bieneusi is an increasingly recognized infection in AIDS patients. We report eight cases of microsporidiosis. All patients were severely immunodepressed. Clinical features were highly variable. Patients were followed up for a mean period of 7.8 months. All patients had persistent infection during the follow-up and spore excretion remained constant. Two patients became asymptomatic during the follow-up. None of the patients presented clinical and echographic signs of biliary involvement. Treatment with albendazole, metronidazole or paromomycin failed to produce a durable clinical response or to eradicate the organism. Cases were identified by stool examination and additionally investigated with light and electron microscopy. It was found that light microscopy was a sensitive method, while electron microscopy was less sensitive but allowed the definition of the infecting species. The modified trichrome stain was a satisfactory method for diagnosis on fecal smears. The calcofluor stain and the combination of DAPI with calcofluor was a rapid and simple staining method for screening.