Acanthamoeba and its pathogenic role in granulomatous amebic encephalitis

Kalra, Samir Kumar; Sharma, Prince; Shyam, Kirti; Tejan, Nidhi; Ghoshal, Ujjala

doi:10.1016/j.exppara.2019.107788

Cited by 87 publications

(96 citation statements)

References 123 publications

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“…The general amoebae biological characteristics include ubiquitous distribution, use of soil and water habitats, air use as dispersal media, and ecologically they participate in bacterial population control [ 1 , 2 ]. However, Acanthamoeba spp.…”

Section: Introductionmentioning

confidence: 99%

“…However, Acanthamoeba spp. are etiology agents of human pathologies, such as amoebic keratitis (AK), granulomatous amoebic encephalitis (GAE) and skin infections [ 2 ]. These protozoans have been more appropriately designated as amphizoic microorganisms, due to their ability to exist in the environment as free-living organisms or as opportunistic parasites.…”

Section: Introductionmentioning

confidence: 99%

“…Diagnosis is usually carried out long delayed, after weeks or months of infection, and currently there is no treatment for affected patients that is 100% effective [ 4 ]. The GAE is a subacute or chronic infection causing necrosis and inflammatory lesions, whose entry route can be hematogenous or through the respiratory tract, affecting mainly immunocompromised people [ 5 ], with multiple sclerosis or diabetes [ 2 , 6 , 7 ]. Nevertheless, clinical GAE cases have occurred in immunocompetent people and patients with organ transplants [ 8 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

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Morphological Description of the Early Events during the Invasion of Acanthamoeba castellanii Trophozoites in a Murine Model of Skin Irradiated under UV-B Light

et al. 2020

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Skin infections have been associated with Acanthamoeba, nevertheless the events during skin invasion and UV-B light effects on it are unknown. The early morphological events of Acanthamoeba castellanii skin invasion are shown in SKH-1 mice that were chronically UV-B light irradiated. Mice that developed skin lesions (group 1) were topical and intradermally inoculated with A. castellanii trophozoites and sacrificed 48 h or 18 days later. Mice that showed no skin lesions (group 2) were intradermally inoculated and sacrificed 24, 48 or 72 h later. Mice ventral areas were considered controls with and without trophozoites intradermally inoculated. Skin samples were processed by histological and immunohistochemistry techniques. In group 1, trophozoites were immunolocalized in dermal areas, hair cysts, sebaceous glands, and blood vessels, and collagen degradation was observed. One of these mice shown trophozoites in the spleen, liver, and brain. In group 2, few trophozoites nearby collagenolytic activity zones were observed. In control samples, nor histological damage and no trophozoites were observed. Adherence and collagenolytic activity by A. castellanii were corroborated in vitro. We can infer that UV-B light irradiated skin could favor A. castellanii invasiveness causing damage in sites as far away as the brain, confirming the invasive capacity and pathogenic potential of these amphizoic amoebae.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Morphological Description of the Early Events during the Invasion of Acanthamoeba castellanii Trophozoites in a Murine Model of Skin Irradiated under UV-B Light

et al. 2020

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“…Free-living amoebae (FLA) of the genus Acanthamoeba are cosmopolitan protozoans commonly found in natural environments, they play a significant ecological role in controlling bacterial populations. Some species of this genus, in addition to being ecologically relevant, are also important in the medical field, due to their ability to exist as free-living organisms and as parasites, becoming a threat to the health and life of the hosts [ 1 , 2 ]. In the cornea, Acanthamoeba are etiological agents of Acanthamoeba keratitis (AK), a painful, vision–threatening infection occurring primarily in immunocompetent persons and contact lens users [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

“…In the central nervous system (CNS), they are etiological agents of granulomatous amoebic encephalitis (GAE), which mostly occurs in people with metabolic, physiological, and immunological disorders, reporting greater than 90% mortality. GAE infection is characterized by a chronic protracted slowly progressive CNS, which also may involve the lungs and skin [ 2 , 4 ].…”

Section: Introductionmentioning

confidence: 99%

Schwann Cell Autophagy and Necrosis as Mechanisms of Cell Death by Acanthamoeba

et al. 2020

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Amoebae of the genus Acanthamoeba are etiological agents of granulomatous amoebic encephalitis (GAE). Recently, through an in vivo GAE model, Acanthamoeba trophozoites were immunolocalized in contact with the peripheral nervous system (PNS) cells—Schwann cells (SC). In this study, we analyzed in greater detail the in vitro early morphological events (1, 2, 3, and 4 h) during the interaction of A. culbertsoni trophozoites (ATCC 30171) with SC from Rattus norvegicus (ATCC CRL-2941). Samples were processed for scanning and transmission electron microscopy as well as confocal microscopy. After 1 h of interaction, amoebae were observed to be adhered to the SC cultures, emitting sucker-like structures associated with micro-phagocytic channels. In addition, evidence of necrosis was identified since edematous organelles as well as multivesicular and multilamellar bodies characteristics of autophagy were detected. At 2 h, trophozoites migrated beneath the SC culture in which necrosis and autophagy persisted. By 3 and 4 h, extensive lytic zones were observed. SC necrosis was confirmed by confocal microscopy. We reported for the first time the induction of autophagic and necrotic processes in PNS cells, associated in part with the contact-dependent pathogenic mechanisms of A. culbertsoni trophozoites.

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