Pathogenic Naegleria sp.—Study of a Strain Isolated from Human Cerebrospinal Fluid

Abstract

53SYNOPSIS. Experimental observation of the pathogenicity of some strains of Hartmannelkz plus the observation of human meningoencephalitis due to small amebas which had a structure compatible with that of Hartmannella in the tissues has suggested the concept af respiratory amebiasis followed by cerebral and other complica- tions.Until recently no cultural evidence was available to identify positively the amebas in the human cases. This report summarizes the isolation of Naegleria sp. (HB-I) from human spinal fluid by mouse inoculation followed by tissue culture of the infected mouse brain. C. Butt and his associates, who submitted this material to us, iso-OME stirains of free-living amebas of the family Hart-s mannellidae can grow in and destroy many different types of tissue culture; many of these isolates are pathogenic for animals. This report presents strong evidence (that another common free-living ameba of the family Schizopyrenidue, genus Naegleria, is similarly endowed with pathogenic capabilities.The spinal fluid from which the isolate was recovered was made available to us by Dr. Cecil Butt and his colleagues(1) who performed the autopsy and who also recovered the ameba in culture. Their findings are reported elsewhere. MATERIALS 1. Escherichia coli. This culture, used by Dr. B. N. Singh as nutrient for soil amebas, was obtained from him in 195T and maintained on Trypticase soy agar slants (transfer several times each week). This organism was originally referred to by Dr Singh and by us as Aerohacter yp. 2 . Naegleria gruheri. Known strains of this ameba growing with associated Gram-negative bacteria were obtained thru the courtesy of Dr. S. L. C h a w of Cincinnati, Ohio, and Prof William Balamuth of Berkeley, California. 3 . Tetramitw rostratus. Cysts of culture No. B 15811'1 were kindly supplied to us by Dr. J. L. Griffin of the Armed Forces Institute of Pathology. 4. Mice. SPF (Lilly) mice of the ND-4 line, caesarian-derived from germ-free animals, were used thruout these tests. 5. Tissue Culture. MK, (Lilly) continuous cell line of monkey kidney cells was utilized in roller tubes, Leighton tubes, or tissue culture bottles with Medium 199 containing 100 unilts of penicillin G and 100 Ng of streptomycin per ml. METHODS Direct microscopic examination.Both phase and ordinary microscopy should be utilized for preliminary examination of all specimens for these amebas. Since some strains of free-living amebas are only sluggbhly motile at 20 C, it is desirable to keep the slide at 37 C during examination. Ordinary clean, sterile slides and cover slips are used to make relatively thin preparations of exudates of body fluids or tissue emulsions. Sealing the cover slip edges with sterile mineral oil applied with a small camel's hair brush will preserve the preparation against drying. lated the N a e g l e k on agar medium with Escherichia coli without antibiotics tat 37 C.The new isolate failed to grow on the medium previously suggested by us for Hartmannella. HB-1 is virulent for laboratory animals and has ...

Observations by Light Microscopy on the Cytopathogenicity of Naegleria Fowleri in Mouse Embryo-Cell Cultures

“…The distinctive CPE caused by trophozoites of N. fowZeri strain HB-1 in ME cells generally conformed to previous brief descriptions of changes in other cell lines (Carter, 1970;Culbertson, 1971 ;Visvesvara and Callaway, 1974). The appearance of intracellular amoebae, particularly in fixed and stained preparations, was noted also by Chang (1974) and Visvesvara and Callaway (1974) although their suggestion that the organisms were engulfed by the cultured cells seems most improbable in the light of the present observations ; time-lapse cinemicrography indicated that the vigorously motile trophozoites could easily evade capture and ingestion by the relatively-static mammalian cells.…”

Identification and classification of the aettological agents of primary amebic meningo‐Encephalitis

“…The dispute over the capriciousness of the interzonal bodies is resolved since Page (1974) has now recognised the presence of interzonal bodies as a constant feature of nuclear division in N. gruberi, as have Rafalko (1947), Singh (1952), Butt et al (1968), Culbertson et al (1968), Chang (1971) and Cursons (1974).…”

Primary Amebic Meningoencephalitis and the Biology of Naegleria Fowleri

“…Naegleria fowleri produces fatal meningoencephalitis in mice (13,18,29,92, and others), guinea pigs (18,30,104), rabbits (29), monkeys (29, .141), and sheep (144). The recent significant fi nding that sheep are susceptible to N. fowled following intrana sal instillation of amebae suggests the possible occurrance of PAM among domestic livestock.…”