Free-Living Amoebae as Hosts for and Vectors of Intracellular Microorganisms with Public Health Significance

Balczun, Carsten; Scheid, Patrick

doi:10.3390/v9040065

Cited by 131 publications

(106 citation statements)

References 145 publications

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“…Beside those bacterial and viral endocytobionts, there are also pathogenic fungi (e.g., Cryptococcus neoformans; Histoplasma capsulatum) and protozoa (Toxoplasma gondii; Cryptosporidium spp.) which live in close association with FLA showing similar effects after the amoebal passage [31,[39][40][41].…”

Section: Fla As Reservoirs For Human Pathogensmentioning

confidence: 69%

“…Listeria monocytogenes, Campylobacter jejuni, Arcobacter butzleri, Vibrio cholera, Yersinia enterocolitica or Salmonella typhimurium (see Table 1) are further examples of pathogenic endocytobionts in Acanthamoeba [29][30][31]. Pseudomonas aeruginosa, Simkania negevensis, Chlamydia-and Ehrlichia-like organisms, Burkholderia pseudomallei, Escherichia coli and Francisella tularensis are also associated with FLA (table 1 is extracted from [31]). Those bacteria are protected against adverse conditions, especially when hiding in cyst forming FLA [32,33].…”

Section: Fla As Reservoirs For Human Pathogensmentioning

confidence: 99%

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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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Section: Fla As Reservoirs For Human Pathogensmentioning

confidence: 69%

Section: Fla As Reservoirs For Human Pathogensmentioning

confidence: 99%

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

Scheid

2018

EWaS3 2018

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“…V. vermiformis is frequently isolated from soil and water environments, including hospital tap water [26]. Interestingly, all three genera have previously been reported to harbor potentially pathogenic intracellular microbes such as Legionella pneumophila [27–29]. Additionally, there are several reports on the interaction of A. castellanii with different pathogenic fungi, and V. vermiformis has been shown to promote Candida spp.…”

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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“…Aus hygienischen Gesichtspunkten empfiehlt es sich, diese Eigenschaften der Amöben mit einzubeziehen, wenn Maßnahmen zur Kontrolle der Wasserqualität geplant werden (siehe auch [56] [45], [46], [47]). Das bedeutet, diese Amöben werden von Bakterien befallen, und diese vermehren sich innerhalb der Amöbenzellen, wodurch diese zu Vektoren werden [48]. In der Vergangenheit wurde angenommen, dass insbesondere mit Pathogenen verseuchte Amöben -genauer deren mit Bakterien beladene Vakuolen -das eigentliche infektiöse Agens für die Legionärskrankheit seien ( [49], [50]).…”

Section: Typical Black Discoloration On a Silicone-joint In A Bathrunclassified

Biofilme mit Amöben, Bakterien und Pilzen im gebauten Umfeld des Menschen

Hofbauer

2018

Bauphysik

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Bei mikrobiellen Untersuchungen von verschiedenen biogenen schwarzen Verfärbungen von Wasserleitungssystemen oder damit verbundenen Einrichtungen wurden unterschiedliche Mikroorganismen festgestellt. Überraschend häufig wurden dabei freilebende Amöben (FLA), insbesonders aus der Gattung Acanthamoeba, beobachtet, die zusammen mit Bakterien und schwarzen Hefen auftraten. Die untersuchten Biofilme legen in dreifacher Hinsicht eine potenzielle hygienische Belastung nahe: das Auftreten potenziell pathogener Amöben, die wahrscheinliche Beteiligung von pathogenen Bakterien und das Vorkommen von opportunistischen Pilzen. Eine charakteristische Kombination von Umweltfaktoren führt zur Entwicklung dieser speziellen Biofilme, nämlich hohe Temperaturen, periodische Feuchte und damit verbundener Wasserstress oder hoher osmotischer Druck bzw. Salzgehalt sowie die Anwendung von Reinigungsmitteln und fallweise von Desinfektionsmitteln.

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Free-Living Amoebae as Hosts for and Vectors of Intracellular Microorganisms with Public Health Significance

Cited by 131 publications

References 145 publications

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

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

A hidden battle in the dirt: soil amoebae interactions withParacoccidioidesspp

Biofilme mit Amöben, Bakterien und Pilzen im gebauten Umfeld des Menschen

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