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Francisella tularensis is a highly infectious, facultative intracellular bacterium which causes epidemics of tularemia in both humans and mammals at regular intervals. The natural reservoir of the bacterium is largely unknown, although it has been speculated that protozoa may harbor it. To test this hypothesis, Acanthamoeba castellanii was cocultured with a(More)
Vibrio cholerae is a highly infectious bacterium responsible for large outbreaks of cholera among humans at regular intervals. A seasonal distribution of epidemics is known but the role of naturally occurring habitats are virtually unknown. Plankton has been suggested to play a role, because bacteria can attach to such organisms forming a biofilm.(More)
Vibrio cholerae species are extracellular, waterborne, gram-negative bacteria that are overwhelmed by predators in aquatic environments. The unencapsulated serogroup V. cholerae O1 and encapsulated V. cholerae O139 cause epidemic and pandemic outbreaks of cholera. It has recently been shown that the aquatic and free-living amoeba Acanthamoeba castellanii is(More)
Acanthamoeba is a genus of free-living amoebae found to be able to host many bacterial species living in the environment. Acanthamoebae and Vibrio cholerae are found in the aquatic environments of cholera endemic areas. Previously it has been shown that V. cholerae O1 and O139 can survive and grow in Acanthamoeba castellanii. The aim of this study was to(More)
The interaction between Shigella dysenteriae or Shigella sonnei and Acanthamoeba castellanii was studied by viable counts, gentamicin assay and electron microscopy. The result showed that Shigella dysenteriae or Shigella sonnei grew and survived in the presence of amoebae for more than 3 weeks. Gentamicin assay showed that the Shigella were viable inside(More)
Shigella flexneri is a Gram-negative bacterium causing the diarrhoeal disease shigellosis in humans. The virulence genes required for invasion are clustered on a large 220 kb plasmid encoding type three secretion system (TTSS) apparatus and virulence factors such as adhesions and invasion plasmid antigens (Ipa). The bacterium is transmitted by contaminated(More)
Acanthamoeba is a genus of FLA, which are environmental eukaryotic cells distributed worldwide in nature [5,6] and they are found to support bacterial growth and survival [5]. Recently, studies have shown that Pseudomonas aeruginosa kills A. castellanii [7] and Aeromonas hydrophila inhibits growth of A. castellanii [8]. Interestingly, V. cholerae O1, O139(More)
Acanthamoebae are free-living amoebae distributed worldwide. They are among the most prevalent protozoa found in the environment, and have been isolated from a wide variety of public water supplies, swimming pools, bottled water, ventilation ducts, soil, air, surgical instruments, contact lenses, dental treatment units and hospitals. Acanthamoebae feed on(More)
AIMS To investigate the hypothesis that amoeba may comprise a significant environmental reservoir for Aeromonas, Acanthamoeba-Aeromonas interaction experiments were performed. METHODS AND RESULTS Acanthamoeba were grown in monoculture and co-cultures with three different species of Aeromonas. Survival, invasion and viable but nonculturable state(More)