Isolation and Characterization of a New Human Microsporidian, Encephalitozoon hellem (n. sp.), from Three AIDS Patients with Keratoconjunctivitis

Abstract

A new human microsporidian was isolated from cultures of Madin-Darby canine kidney cells incubated with conjunctival scrapings or corneal tissues from three AIDS patients with keratoconjunctivitis. The three isolates were morphologically similar to Encephalitozoon cuniculi. The spores averaged 1 x 1.5-2.0 microns, had six to eight polar filament coils, displayed monokaryotic nuclei, and possessed relatively thick endospores with irregularly shaped exospores. Organisms developed within a parasitophorous vacuole. By SDS-PAGE analysis, the three isolates appeared to be identical but were different from E. cuniculi. Identical banding patterns on Western blots of the three isolates were expressed by each patient's serum. By Western immunoblotting, murine antisera to E. cuniculi reacted to several antigens of the new AIDS-related microsporidian, whereas murine antisera bound weakly to Nosema corneum. The name Encephalitozoon hellem (n. sp.) is proposed to identify this new human microsporidian.

Gain and loss of multiple functionally related, horizontally transferred genes in the reduced genomes of two microsporidian parasites

“…Spores from E. hellem [ATCC 50504; originally isolated from humans (28)] were grown in the rabbit kidney fibroblast cell line RK 13 (ATCC CCL-37) with RPMI 1640 (Sigma-Aldrich) supplemented with 5% (vol/vol) foetal bovine serum (FBS), 2 mM L-glutamine, and antibiotics (penicillin, 100 U mL, and streptomycin, 100 μg/mL). T75 flasks were incubated at 37°C with 5% CO 2 , and culture medium was replaced two or three times per week.…”

Experimental meningoencephalomyelitis by Encephalitozoon cuniculi in cyclophosphamide-immunosuppressed mice

“…Mice from groups I and II were inoculated with 2x10 8 E. cuniculi spores by intraperitoneal route. These spores were grown in Madin Darby Canine Kidney (MDCK) cells and purified by centrifugation over 50% Percoll (Pharmacia) as described by Didier et al 8 .…”

Microsporidial Infections in Immunodeficient and Immunocompetent Patients

“…Another microsporidial species, Septata intestinalis, has recently been described as a cause ofintestinal and disseminated infection in a small number of HIV-infected persons [15,16]. Cases of Hl V-associated encephalitozoonosis due to Encephalitozoon hellem [17], and possibly E. cuniculi. are being recognized with increasing frequency.…”

“…The spectrum of recognized Encephalitozoon-associated disease in patients with AIDS appears to be expanding and now includes keratoconjunctivitis, sinusitis, bronchiolitis, nephritis, ureteritis, cystitis, hepatitis, and peritonitis. [3,4,12,[17][18][19][20][21][22][23]. A single case of pieisto phora myositis in a patient with AIDS has also recently been reported [24].…”