a1 Department of Medical Microbiology, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
a2 Department of Internal Medicine (AIDS- Unit), University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
a3 Department of Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
a4 Department of Biology, Imperial College London, London 5W7 2AZ, UK
Two species of microsporidia, Enterocytozoon bieneusi and Septata intestinalis have been reported as intestinal parasites of AIDS patients. In attempts to establish E. bieneusi in vitro, spores were concentrated from stool samples from 4 AIDS patients with biopsy-proven E. bieneusi infections. After sterilization of the concentrate in antibiotic solution, the spores were added to monolayers of RK13 cells grown on the membranes of Transwells. Cultures were established from 7 stool samples from the 4 patients but in every case the species established was S. intestinalis not E. bieneusi. On retrospective examination of the stools, a very small number of spores of a size comparable to that of S. intestinalis was found but this species was not detected in biopsies. Typical septate vacuoles containing Type I tubules were observed in vitro but in contrast to the original description, meronts were intravacuolar and sporogony was mainly disporoblastic. The cultivation system, used for the first time for microsporidia, revealed the presence of unsuspected S. intestinalis infections and indicates that this species may be much more common than hitherto suspected. S. intestinalis has not previously been cultured.
(Received October 25 1993)
(Revised February 07 1994)
(Accepted February 10 1994)