CHARACTERIZATION OF ENCEPHALITOZOON (SEPTATA) INTESTINALIS ISOLATES CULTURED FROM NASAL-MUCOSA AND BRONCHOALVEOLAR LAVAGE FLUIDS OF 2 AIDS PATIENTS

Microsporidia are obligate intracellular protozoan parasites that can cause opportunistic infections in AIDS patients. Species from five gen era of microsporidia are presently known to infect man. One species, S eptata intestinalis originally was detected in stool specimens of indi viduals with chronic diarrhea and subsequently was found to disseminat e to the kidneys, lungs, and nasal sinuses. This organism has since be en reclassified as Encephalitozoon and in this study, we report the cu lture of Encephalitozoon intestinalis from a bronchoalveolar lavage sp ecimen and a nasal mucus aspirate of two AIDS patients living in the U SA. The bronchoalveolar and nasal microsporidian isolates grew in seve ral continuous cell lines including RK-13, MDCK, HT-29, Caco-2, Vero, and 1047. Transmission electron microscopy of the clinical and cell cu lture specimens revealed that the new isolates appeared to be E. intes tinalis based on morphology and growth of organisms in septated membra ne-bound parasitophorous vacuoles. The new E. intestinalis isolates we re characterized and compared with the first isolated E. intestinalis that was cultured from stool to confirm their identity and to determin e if there existed any minor differences, as seen in the closely relat ed Encephalitozoon cuniculi strains. By the methods of sodium dodecyl sulfate-polyacrylamide gel electrophoresis staining for proteins and c arbohydrates, Western blot immunodetection, and polymerase chain react ion-based methods with restriction endonuclease digestion, double-stra nded DNA heteroduplex mobility shift analysis, and DNA sequencing of t he ribosomal DNA intergenic spacer region, the new isolates were ident ical to each other and to the reference isolate of E. intestinalis. In addition, with any of these methods, the E. intestinalis organisms co uld be distinguished from the three E. cuniculi strains, Encephalitozo on hellem, and Vittaforma corneae, which is important for diagnostics, therapeutic strategies, and epidemiology.