Allovahlkampfia spelaea Causing Keratitis in Humans

Tolba, Mohammed Essa Marghany; Huseein, Enas Abdelhameed Mahmoud; Farrag, Haiam Mohamed Mahmoud; Mohamed, Hanan El Deek; Kobayashi, Seiki; Suzuki, Jun; T., Ali,; Sugano, Sumio

doi:10.1371/journal.pntd.0004841

Cited by 21 publications

(18 citation statements)

References 18 publications

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“…Acanthamoeba is a genus of soil amoeba that can cause keratitis and granulomatous amoebic encephalitis [24]. A. spelaea was first identified in 2009 and it was also involved in human keratitis, but there is little information about it in the literature [25]. V. vermiformis is frequently isolated from soil and water environments, including hospital tap water [26].…”

Section: Discussionmentioning

confidence: 99%

A hidden battle in the dirt: soil amoebae interactions withParacoccidioidesspp

Albuquerque

Nicola

Magnabosco

et al. 2019

Preprint

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26Paracoccidioides spp. are thermodimorphic pathogenic fungi endemic to Latin America. 27 Predation is believed to drive the evolution of virulence for soil saprophytes. We evaluated the 28 presence of environmental amoeboid predators in soil from armadillo burrows where 29Paracoccidioides had been previously detected and tested if interaction of Paracoccidioides with 30 amoebae increased fungal virulence. Nematodes, ciliates and amoebaeall potential predators of 31 fungigrew in cultures from soil samples. Microscopical observation and ITS sequencing 32 identified the amoebae as Acanthamoeba spp, Allovahlkampfia spelaea and Vermamoeba 33 vermiformis. These three amoebae efficiently ingested, killed and digested Paracoccidioides spp. 34 yeast cells, as did laboratory-adapted axenic Acanthamoeba castellanii. Sequential co-cultivation 35of Paracoccidioides with A. castellanii selected for phenotypical traits related to survival of the 36 fungus within a natural predator as well as in murine macrophages and in vivo (Galleria 37 mellonella and mice). This increase in virulence is linked to the accumulation of cell wall alpha-38 glucans, polysaccharides that masks recognition of fungal molecular patterns by host pattern 39 recognition receptors. Altogether, our results indicate that Paracoccidioides inhabits a complex 40 environment with multiple amoeboid predators that can exert selective pressure to guide the 41 evolution of virulence traits. 42 43

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Section: Discussionmentioning

confidence: 99%

A hidden battle in the dirt: soil amoebae interactions withParacoccidioidesspp

Albuquerque

Nicola

Magnabosco

et al. 2019

Preprint

View full text Add to dashboard Cite

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“…Allovahlkampfia spelae was just recently identified as the etiological agent of a human keratitis [21]. Dictyostelium polycephalum, a social amoeba (slime mold; belonging to the Mycetozoa), was also involved in a keratitis case of an immunocompetent patient [22].…”

Section: Other Fla With Pathogenic Capability Discovered To Datementioning

confidence: 99%

Free-Living Amoebae as Human Parasites and Hosts for Pathogenic Microorganisms

Scheid

2018

EWaS3 2018

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Free-living amoebae (FLA) can be found both in natural aquatic environments and in artificial, man-made aquatic environments. For a long time, (naked) FLA were considered to be harmless protozoa of soil and water. However, research since the 1960s has demonstrated that FLA can be pathogenic to humans and animals with nearly 100% morbidity from some strains. As etiological agents of the so-called Acanthamoebiasis, the Acanthamoebae can trigger several specific diseases (or symptoms) in humans. The amoebiasis of the central nervous system is called granulomatous amebic encephalitis (GAE), when Acanthamoebae are the etiological agents, showing subacute to chronic progress. GAE differs clinically from the primary amoebic meningoencephalitis (PAM(E)), which is caused by Naegleria fowleri. The Acanthamoeba keratitis is not necessarily associated with an immune suppression, but rather with a trauma, exposure to contaminated water or, particularly, the improper handling of contact lenses, which promotes infection. The clinical picture of GAE by Balamuthia mandrillaris is characterized by headache and neck stiffness. The infection is chronic and the time between infection and appearance of neurological symptoms may range from one month to about two years. The prevalence of FLA in water networks is associated with biofilms, where the amoebae live within a biocoenosis sympatric with other microorganisms. These biofilms serve as feeding grounds for the FLA and provide protection to a certain degree while the FLA adhere to the surfaces. In such a biocoenosis there are multiple interactions between FLA and other microorganisms: In addition to their role as pathogens, FLA are known to serve as host of and vehicles for diverse intracellular organisms (bacteria, viruses, eucaryonts), some of them being natural human pathogens. They act as reservoir or vehicle for various microorganisms such as various Legionella sp., Listeria monocytogenes, Pseudomonas aeruginosa and some Mycobacterium sp. In the cyst-stage of the FLA these intracellular organisms (endocytobionts) are protected to a high degree against any adverse environment (FLA as “Trojan horse”). This host-endocytobiont relationship may further lead to health risks in terms of the development of pathogenicity/virulence and antibiotic resistance (FLA as “Trainings ground”).

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“…One heterolobosean amoeboflagellate, Naegleria fowleri is dangerously pathogenic for humans (Carter 1970;Siddiqui et al 2016). Additionally, Allovahlkampfia spelaea is reported to infect the human eye (Huseein et al 2016;Tolba et al 2016) and to host bacteria known to be human pathogens (Mohamed et al 2016) making this genus particularly worthy of study.…”

Section: Introductionmentioning

confidence: 99%

Allovahlkampfia minuta nov. sp., (Acrasidae, Heterolobosea, Excavata) a New Soil Amoeba at the Boundary of the Acrasid Cellular Slime Moulds

2017

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We report the isolation of a new species of Allovahlkampfia, a small cyst-forming heterolobosean soil amoeba. Phylogenetic analysis of the 18S rDNA and the internal transcribed spacers indicates that Allovahlkampfia is more closely related to the acrasids than to other heterolobosean groups and indicates that the new strain (GF1) groups with Allovahlkampfia tibetiensis and A. nederlandiensis despite being significantly smaller than these and any other described Allovahlkampfia species. GF1 forms aggregated cyst masses similar to the early stages of Acrasis sorocarp development, in agreement with the view that it shares ancestry with the acrasids. Time-lapse video microscopy reveals that trophozoites are attracted to individuals that have already begun to encyst or that have formed cysts. Although some members of the genus are known to be pathogenic the strain GF1 does not grow above 28 o C nor at elevated osmotic conditions, indicating that it is unlikely to be a pathogen.

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Allovahlkampfia spelaea Causing Keratitis in Humans

Cited by 21 publications

References 18 publications

A hidden battle in the dirt: soil amoebae interactions withParacoccidioidesspp

A hidden battle in the dirt: soil amoebae interactions withParacoccidioidesspp

Free-Living Amoebae as Human Parasites and Hosts for Pathogenic Microorganisms

Allovahlkampfia minuta nov. sp., (Acrasidae, Heterolobosea, Excavata) a New Soil Amoeba at the Boundary of the Acrasid Cellular Slime Moulds

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