Polyclonal andMonoclonal Antibody andPCR-Amplified Small-Subunit rRNAIdentification ofa Microsporidian, Encephalitozoon hellem, Isolated froman AIDS Patient withDisseminated Infection

eukaryotic protozoathatare obligate intracellular parasites. Theyare knowntoparasitize almost everygroup ofanimals including humans. Recently, microsporidia haveincreasingly beenfoundtoinfect patients withAIDS.Five genera (Encephalitozoon,Enterocytozoon, Nosema, Septata, andPleistophora) ofmicrosporidia are knowntoinfect humans. Enterocytozoon organisms causegastrointestinal disease ina majority ofAIDSpatients withmicrosporidiosis. However, a smaller, butan expanding, numberofpatients withAIDSarebeing diagnosed withocular and disseminated infection withEncephalitozoon hellem. Although microsporidial sporescanbeidentified inclinical samples byastaining technique suchasonewithWeber's chromotrope stain, identification tothespecies level isdependent on cumbersome andtime-consuming electron microscopy. We haverecently isolated and established incontinuous culture several strains ofE.hellem fromurine, bronchoalveolar lavage, andsputum samples fromAIDSpatients withdisseminated microsporidiosis. We developed polyclonal andmonoclonal antibodies andPCRprimers toa strain ofE.heUemthat can beusedsuccessfully toidentify E.heUemfrom other species ofmicrosporidia either inclinical specimens orincultures established fromclinical specimens. Since patients infected withEncephalitozoon spp.areknowntorespond favorably toalbendazole, identification oftheparasite tothespecies level wouldbeinvaluable inthetreatment ofdisseminated microsporidiosis.