QUANTITATIVE LIGHT-MICROSCOPIC DETECTION OF ENTEROCYTOZOON-BIENEUSI IN STOOL SPECIMENS - A LONGITUDINAL-STUDY OF HUMAN IMMUNODEFICIENCY VIRUS-INFECTED MICROSPORIDIOSIS PATIENTS

The clinical course of microsporidiosis caused by Enterocytozoon biene usi and the pattern of intestinal shedding of spores have not been cor related, at least in part because detection of E. bieneusi in stools i s more difficult than detection of other protozoa because of its small er size and less intense staining. We examined with a modified trichro me stain 124 stool specimens collected over a 2-year follow-up period from 23 human immunodeficiency virus-infected patients with electron m icroscopic-proven E. bieneusi infection and correlated the results wit h electron microscopic observations from duodenal biopsy specimens tak en at the beginning of the study period. E. bieneusi was detected in t he stool at least once in 74% (17 of 23) of all patients, in 100% (9 o f 9) of patients in whose tissue moderate or abundant numbers of paras ites were seen, and in 57% (8 of 14) of patients in whose tissue few p arasites were seen. In two patients with abundant tissue parasites, ma ny microsporidia were detected in every stool specimen (13 of 13) duri ng the follow-up period, whereas among the patients with few tissue pa rasites, only 23% (15 of 64) of stool specimens were positive. Further more, if spore stages as well as plasmodial stages were detected in ti ssue, stool specimens were more likely to be positive. Although most o f the heavily infected stools were from patients with chronic diarrhea , microsporidia were detected in 33, 28, and 42% of stool specimens fr om patients with nil, intermittent, and chronic diarrhea patterns, res pectively. Although quantitation of E. bieneusi spores in stool specim ens was closely correlated with quantitation in tissue, it was not cor related with reported patterns of diarrhea.