DEVELOPMENT AND APPLICATION OF GENETIC PROBES FOR DETECTION OF ENTEROCYTOZOON-BIENEUSI IN FORMALIN-FIXED STOOLS AND IN INTESTINAL BIOPSY SPECIMENS FROM INFECTED PATIENTS

The microsporidium Enterocytozoon bieneusi is closely linked to wastin g and diarrhea in a high proportion of individuals with AIDS. However, its relative contribution to disease is uncertain because diagnosis u ntil recently depended on procedures involving endoscopy. A sensitive PCR technique which amplifies a fragment of the small-subunit rRNA gen e of E. bieneusi from formalin-fixed stool samples was developed. Of 8 0 formalin-fixed stool samples collected from 74 Zimbabweans and 6 U.S . patients who were human immunodeficiency virus positive, 50% tested positive for E. bieneusi by PCR, whereas 24% tested positive for E. bi eneusi by light microscopy of trichrome-stained fecal smears. In addit ion, we describe an in situ hybridization technique which detected and identified E. bieneusi as the causative agent in all six intestinal b iopsy specimens tested. Both the PCR and in situ hybridization procedu res are sensitive diagnostic tools which will complement currently ava ilable techniques and enable the differentiation of E. bieneusi from o ther microsporidia to be made.