A systematic analysis of Acanthamoeba genotype frequency correlated with source and pathogenicity: T4 is confirmed as a pathogen-rich genotype

Maciver, Sutherland K.; Asif, Muhammad; Simmen, Martin W.; Lorenzo‐Morales, Jacob

doi:10.1016/j.ejop.2012.11.004

Cited by 96 publications

(60 citation statements)

References 25 publications

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“…Acanthamoeba genotype T4, the predominant genotype in the current study, is the most important causative agent of Acanthamoeba -keratitis (AK), an infection that concerns particularly people wearing soft contact lenses (Risler et al 2013), and as has been shown recently, the genotype most often associated with human disease (Maciver et al 2013). Of the other genotypes found, genotypes T5 and T11, have also been described to cause keratitis (Iovieno et al 2010; Lorenzo-Morales et al 2011).…”

Section: Discussionmentioning

confidence: 75%

“…Of the other genotypes found, genotypes T5 and T11, have also been described to cause keratitis (Iovieno et al 2010; Lorenzo-Morales et al 2011). Interestingly, T5 has been reported to be found most often in water samples (Maciver et al 2013). Furthermore, several genotypes of Acanthamoeba , including particularly also T4, can cause granulomatous amebic encephalitis (GAE), a life-threatening infection of the brain occurring mainly in immunocompromised hosts as e.g.…”

Section: Discussionmentioning

confidence: 99%

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Free-living amoebae (FLA) co-occurring with legionellae in industrial waters

Scheikl

Sommer

Kirschner

et al. 2014

European Journal of Protistology

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Legionella pneumophila is known as the causative agent of Legionnaires’ disease and free-living amoebae (FLA) can serve as vehicles for legionellae. The aim of this study was to screen industrial waters for the occurrence of FLA and their co-occurrence with legionellae. A total of 201 water samples, including 129 cooling waters and 72 process waters, and 30 cooling lubricants were included in the study. Treated waters were screened periodically, pre and post treatment. Altogether, 72.6% of the water samples were positive for FLA, acanthamoebae being most prevalent (in 23.9% of the samples) followed by Vermamoeba vermiformis (19.4%). Only one cooling lubricant was positive (Acanthamoeba genotype T4). Legionella spp. were detected in 34.8% of the water samples and in 15% in high concentrations (>1000 CFU/100 ml). Altogether, 81.4% of the Legionella-positive samples were positive for FLA by standard methods. By applying a highly sensitive nested PCR to a representative set of random samples it was revealed that Legionella spp. always co-occurred with Acanthamoeba spp. Although the addition of disinfectants did influence amoebal density and diversity, treated waters showed no difference concerning FLA in the interphases of disinfection. It appears that FLA can re-colonize treated waters within a short period of time.

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Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Free-living amoebae (FLA) co-occurring with legionellae in industrial waters

Scheikl

Sommer

Kirschner

et al. 2014

European Journal of Protistology

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“…The T4 genotype is the most common genotype related to amoebic infections, and also it is the most commonly isolated genotype from the environment (3,15). Nevertheless, its association with pathogenicity is not explained by its apparent abundance alone (16).…”

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confidence: 99%

Statins and Voriconazole Induce Programmed Cell Death in Acanthamoeba castellanii

Martín-Navarro

López-Arencibia

Sifaoui

et al. 2015

Antimicrob Agents Chemother

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cMembers of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a lifethreatening encephalitis. In order to treat those infections properly, it is necessary to target the treatment not only to the trophozoite but also to the cyst. Furthermore, it may be advantageous to avoid parasite killing by necrosis, which may induce local inflammation. We must also avoid toxicity of host tissue. Many drugs which target eukaryotes are known to induce programmed cell death (PCD), but this process is poorly characterized in Acanthamoeba. Here, we study the processes of programmed cell death in Acanthamoeba, induced by several drugs, such as statins and voriconazole. We tested atorvastatin, fluvastatin, simvastatin, and voriconazole at the 50% inhibitory concentrations (IC 50 s) and IC 90 s that we have previously established. In order to evaluate this phenomenon, we investigated the DNA fragmentation, one of the main characteristics of PCD, with quantitative and qualitative techniques. Also, the changes related to phosphatidylserine exposure on the external cell membrane and cell permeability were studied. Finally, because caspases are key to PCD pathways, caspase activity was evaluated in Acanthamoeba. All the drugs assayed in this study induced PCD in Acanthamoeba. To the best of our knowledge, this is the first study where PCD induced by drugs is described quantitatively and qualitatively in Acanthamoeba.

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“…Nevertheless, a recent systematic analysis of Acanthamoeba genotype frequency correlated with source and pathogenicity concluded that T4 is in fact the genotype most often associated with human disease, even after its abundance in the general environment is taken into account. Furthermore, T3 and T11 are closest relatives to T4 and they are the second and third most often associated with AK [52]. Further epidemiological studies on the pathogenicity capacity of genotype T3 should be performed to confirm the pathogenic status of genotype T3 in both the environment and clinical cases.…”

Section: Discussionmentioning

confidence: 99%

Morphological Features andIn VitroCytopathic Effect ofAcanthamoeba griffiniTrophozoites Isolated from a Clinical Case

González‐Robles

Salazar‐Villatoro

Omaña‐Molina³

et al. 2014

Journal of Parasitology Research

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Light and transmission electron microscopy observations are reported on the structure and in vitro cytopathic effect of Acanthamoeba griffini trophozoites isolated from a clinical case. Live trophozoites were moderately active with a remarkable pleomorphism which changed from ovoid to quite elongated shapes. When moving, amoebae formed cytoplasmic projections such as wide lamellae and acanthopodia of diverse size and thickness which contain a significant amount of actin. Ultrastructurally, the cytoplasm showed the main organelles found in other free-living amoebae. Coincubation of trophozoites with MDCK cell monolayers resulted in a local damage to target cells after 24 h of interaction, suggesting that the cytopathic effect is contact-dependent. By transmission electron microscopy, amoebae appeared to engulf small portions of the MDCK cells; however, the cells that were not in contact with trophozoites had an unaltered morphology. When epithelial monolayers were incubated with conditioned medium for 24 h, small areas of cell injury were also observed. The phylogenetical analysis as well as the sequencing of the acquired amplified product for the DF3 region of the amoebae isolate confirmed that it belongs to genotype T3, which includes other pathogenic amoebae; besides the activity of two drugs currently used against Acanthamoeba was tested on A. griffini.

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A systematic analysis of Acanthamoeba genotype frequency correlated with source and pathogenicity: T4 is confirmed as a pathogen-rich genotype

Cited by 96 publications

References 25 publications

Free-living amoebae (FLA) co-occurring with legionellae in industrial waters

Free-living amoebae (FLA) co-occurring with legionellae in industrial waters

Statins and Voriconazole Induce Programmed Cell Death in Acanthamoeba castellanii

Morphological Features andIn VitroCytopathic Effect ofAcanthamoeba griffiniTrophozoites Isolated from a Clinical Case

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