IN-VITRO GROWTH OF THE MICROSPORIDIAN SEPTATA-INTESTINALIS FROM AN AIDS PATIENT WITH DISSEMINATED ILLNESS

A new species of microsporidian, Septata intestinalis, was recently re cognized as an opportunistic pathogen of AIDS patients. In this study, it was cultured from the nasopharyngeal aspirate of a human immunodef iciency virus type 1-infected patient with disseminated microsporidios is. In human embryonic lung cells exposed to S. intestinalis, a cytopa thic effect appeared within 28 days as foci of rounded up cells. Thin- section electron microscopy showed a variety of developmental stages o f the microsporidium within parasitophorous vacuoles. In monocyte-deri ved macrophages, evidence of infection and development of the parasite was demonstrated by light and electron microscopy. In both infected h uman embryonic lung cells and monocyte-derived macrophages, a network of septa separated individual spores. Partial sequencing of the RNA sm all-subunit gene (16S rDNA gene) confirmed the identity of this parasi te as S. intestinalis. This is the first report of the isolation of S. intestinalis in vitro and provides evidence that the parasite can be disseminated by macrophages.