Hartmannella (Acanthamoeba): Experimental Chronic, Granulomatous Brain Infections Produced by New Isolates of Low Virulence

Culbertson, C. G.; Ensminger, P. W.; Overton, W. M.

doi:10.1093/ajcp/46.3.305

Cited by 55 publications

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“…Lesions present in the nasal mucosa and brain contain trophozoites and cysts. Mice exhibit symptoms of neurological disorders including circling movement, difficulties with equilibrium, hyperactivity, and convulsive seizures (95,97,98).…”

Section: Models Of Acanthamoeba Infections Animal Models Of Granulomamentioning

confidence: 99%

Acanthamoebaspp. as Agents of Disease in Humans

2003

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Acanthamoeba spp. are free-living amebae that inhabit a variety of air, soil, and water environments. However, these amebae can also act as opportunistic as well as nonopportunistic pathogens. They are the causative agents of granulomatous amebic encephalitis and amebic keratitis and have been associated with cutaneous lesions and sinusitis. Immuno compromised individuals, including AIDS patients, are particularly susceptible to infections with Acanthamoeba. The immune defense mechanisms that operate against Acanthamoeba have not been well characterized, but it has been proposed that both innate and acquired immunity play a role. The ameba's life cycle includes an active feeding trophozoite stage and a dormant cyst stage. Trophozoites feed on bacteria, yeast, and algae. However, both trophozoites and cysts can retain viable bacteria and may serve as reservoirs for bacteria with human pathogenic potential. Diagnosis of infection includes direct microscopy of wet mounts of cerebrospinal fluid or stained smears of cerebrospinal fluid sediment, light or electron microscopy of tissues, in vitro cultivation of Acanthamoeba, and histological assessment of frozen or paraffin-embedded sections of brain or cutaneous lesion biopsy material. Immunocytochemistry, chemifluorescent dye staining, PCR, and analysis of DNA sequence variation also have been employed for laboratory diagnosis. Treatment of Acanthamoeba infections has met with mixed results. However, chlorhexidine gluconate, alone or in combination with propamidene isethionate, is effective in some patients. Furthermore, effective treatment is complicated since patients may present with underlying disease and Acanthamoeba infection may not be recognized. Since an increase in the number of cases of Acanthamoeba infections has occurred worldwide, these protozoa have become increasingly important as agents of human disease

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Section: Models Of Acanthamoeba Infections Animal Models Of Granulomamentioning

confidence: 99%

Acanthamoebaspp. as Agents of Disease in Humans

2003

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“…Acanthamoeba species are now recognized as the cause of Acanthamoeba keratitis and granulomatous Acanthamoeba encephalitis (GAE) in humans (7,11). Acanthamoeba keratitis is an increasingly common and severe corneal infection.…”

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confidence: 99%

Development of Colorimetric Microtiter Plate Assay for Assessment of Antimicrobials against Acanthamoeba

et al. 2005

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We have developed and optimized a 96-well microtiter plate assay, based on the reduction of alamarBlue, to assess the efficacies of much needed new antimicrobials against Acanthamoeba species. This assay has been optimized for determination of drug efficacy against two potentially pathogenic species, Acanthamoeba castellanii and Acanthamoeba polyphaga, and has been validated by comparison of their relative susceptibilities to chlorhexidine, a drug widely used to treat Acanthamoeba keratitis. The results demonstrate that the assay is comparable to a manual counting assay and that A. polyphaga is more resistant to chlorhexidine than A. castellanii. Thus, by use of the manual counting assay, 3.125 M chlorohexidine was almost completely effective against A. castellanii, whereas this concentration was less than 20% effective against A. polyphaga. Similar results were obtained by the alamarBlue assay. The new assay was used to determine the relative susceptibilities of A. castellanii and A. polyphaga to the alkylphosphocholines (APCs) hexadecylphosphocholine (hexadecyl-PC; miltefosine) and octadecylphosphocholine (octadecyl-PC) as well as an alkylgycerolphosphocholine, edelfosine. Both APCs studied were equally effective against A. castellanii, but octadecyl-PC was less effective than hexadecyl-PC against A. polyphaga. Both APCs were more effective than edelfosine against both Acanthamoeba species. A. polyphaga was found to be significantly less susceptible to each of the phosphocholine analogues. The newly described assay offers a number of advantages over those described previously. It is less labor-intensive than previously described assays and is sensitive and rapid, and the results can be read in a nonsubjective manner. As it is based on a standard 96-well, microtiter plate, it is amenable to automation and high throughput.

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“…Depuis la décou verte de Culbertson (1959) la pathogénicité du genre Acanthamoeba est de plus en plus souvent rapportée aussi bien sur le plan expérimental chez l'animal (Culbertson, 1965(Culbertson, et 1966Kasprzak et Mazur, 1972 ;Martinez et coll., 1975) que chez l'homme où les Acanthamoeba peuvent être responsables d'un syndrome de M.E.A.P. d'évo lution particulière (Patras et Andujar, 1966 ;Calicott et coll., 1968 ;Jager et Stamm, 1972 ;Robert et Rorke, 1973 ;Bhagwandeen et coll., 1974 ;Ringsted et coll., 1976), ou associées à des affections diverses de l'oeil (Nagington et coll., 1974) ou de l'oreille (Jakovljevich et Talis 1969).…”

Section: Resultsunclassified

Étude sur la présence d’« amibes libres » dans les eaux des piscines lyonnaises

Pernin

Riany

1978

Ann. Parasitol. Hum. Comp.

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Résumé.Près de 90 °/o des 44 prélèvements d'eau effectués dans 9 piscines lyonnaises renfer maient des amibes. A partir de ceux-ci, 85 souches ont pu être séparées.Malgré l'extrême diversité des espèces rencontrées, les souches appartenant aux genres Acanthamoeba et Hartmannella prédominent. En revanche le genre Naegleria paraît excep tionnel : il n'a pu être isolé qu'une seule fois directement à partir de l'eau des bassins. Summary.Study on the presence of « free-living » amoebae in the swimming-pools of Lyon.About 90 % among 44 water samples executed in 9 swimming-pools of Lyon contained amoebae. From these prelevements, 85 strains have been separated.In spite of the great diversity of the species isolated, the strains belonging to genus Acanthamoeba and Hartmannella prevail. In return, the genus Naegleria seems to be rare : it has been isolated only one time directly from water of swimming-pools.

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Hartmannella (Acanthamoeba): Experimental Chronic, Granulomatous Brain Infections Produced by New Isolates of Low Virulence

Cited by 55 publications

References 0 publications

Acanthamoebaspp. as Agents of Disease in Humans

Acanthamoebaspp. as Agents of Disease in Humans

Development of Colorimetric Microtiter Plate Assay for Assessment of Antimicrobials against Acanthamoeba

Étude sur la présence d’« amibes libres » dans les eaux des piscines lyonnaises

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