Trojan Horses of the microbial world: protozoa and the survival of bacterial pathogens in the environment

Barker, John; Brown, M. R. W.

doi:10.1099/00221287-140-6-1253

Cited by 371 publications

(285 citation statements)

References 11 publications

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“…Some of these bacteria are pathogenic in humans, and amoebae have been suggested as representative environmental reservoirs that act as 'Trojan horses' of the microbial world (Barker & Brown, 1994). As a result of this role, amoebae have attracted the attention of clinical microbiologists during recent decades.…”

Section: Introductionmentioning

confidence: 99%

Amoeba co-culture of soil specimens recovered 33 different bacteria, including four new species and Streptococcus pneumoniae

et al. 2009

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Amoeba-resistant bacteria (ARB), such as Legionella spp., are currently regarded as potential human pathogens that live in the natural environment, and thus their habitat is regarded as a reservoir of human pathogens. To detect ARB in human and environmental samples, co-culture with amoebae has been demonstrated to be an efficient tool. However, to date, only water samples from cooling towers and hospital water supplies have been investigated as possible reservoirs of ARB using this procedure. In the present study, we studied the ARB population of 11 diverse soil and sand sources in proximity to human environments; these sources included the university, the station, hospitals, the square, parks and public beaches in the city of Marseilles, France. As a result, a total of 33 different species of ARB were identified. The ability to grow within and/or lyse amoebae was demonstrated, for what is believed to be the first time, for several species; moreover, 20 of the isolates (61 %), including Streptococcus pneumoniae, have been described as human pathogens. However, Legionella spp. were not isolated. Four isolates are likely to be the members of new or uncharacterized genera or species, and their capability to be human pathogens needs to be determined. This preliminary work demonstrates that soils and sands in the vicinity of humans are reservoirs of human pathogenic ARB.

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Section: Introductionmentioning

confidence: 99%

Amoeba co-culture of soil specimens recovered 33 different bacteria, including four new species and Streptococcus pneumoniae

et al. 2009

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“…Besides their role as bacteriovores, acanthamoebae are also facultative human pathogens that can cause keratitis, mainly in contact lens wearers, and granulomatous encephalitis in immunocompromised individuals (Marciano-Cabral and Cabral, 2003). Moreover, Acanthamoeba and other free-living amoebae can act as vectors for bacteria that resist degradation after phagocytosis (Fritsche et al, 1993;Barker and Brown, 1994;Greub and Raoult, 2004). Indeed, as they were found to be associated with Legionella pneumophila (Rowbotham, 1980) and a number of other pathogenic bacteria such as Francisella tularensis (Abd et al, 2003) and Mycobacterium bovis (Taylor et al, 2003), free-living amoebae have been dubbed 'trojan horses of the microbial world' (Barker and Brown, 1994).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, Acanthamoeba and other free-living amoebae can act as vectors for bacteria that resist degradation after phagocytosis (Fritsche et al, 1993;Barker and Brown, 1994;Greub and Raoult, 2004). Indeed, as they were found to be associated with Legionella pneumophila (Rowbotham, 1980) and a number of other pathogenic bacteria such as Francisella tularensis (Abd et al, 2003) and Mycobacterium bovis (Taylor et al, 2003), free-living amoebae have been dubbed 'trojan horses of the microbial world' (Barker and Brown, 1994). Further studies on the vector role of free-living amoebae also revealed the existence of several previously unknown Chlamydia-like endosymbionts (Kahane et al, 1993;Amann et al, 1997;Rurangirwa et al, 1999;Horn et al, 2000;Collingro et al, 2005;Horn, 2008;Greub, 2009) whose potential as human pathogens is still being evaluated.…”

Section: Introductionmentioning

confidence: 99%

Proteomic aspects of Parachlamydia acanthamoebae infection in Acanthamoeba spp.

et al. 2010

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The free-living but facultatively pathogenic amoebae of the genus Acanthamoeba are frequently infected with bacterial endosymbionts that can have a profound influence on the physiology and viability of their host. Parachlamydia acanthamoebae, a chlamydial endosymbiont in acanthamoebae, is known to be either symbiotic or lytic to its host, depending on the ambient conditions, for example, temperature. Moreover, parachlamydiae can also inhibit the encystment process in Acanthamoeba, an essential survival strategy of their host for the evasion of chemotherapeutic agents, heat, desiccation and radiation. To obtain a more detailed picture of the intracellular interactions of parachlamydiae and acanthamoebae, we studied parachlamydial infection in several Acanthamoeba isolates at the proteomic level by means of two-dimensional gel electrophoresis (2DE) and mass spectrometry. We observed that P. acanthamoebae can infect all three morphological subtypes of the genus Acanthamoeba and that the proteome pattern of released P. acanthamoebae elementary bodies was always practically identical regardless of the Acanthamoeba strain infected. Moreover, by comparing proteome patterns of encysting cells from infected and uninfected Acanthamoeba cultures, it was shown that encystment is blocked by P. acanthamoebae at a very early stage. Finally, on 2D-gels of purified P. acanthamoebae from culture supernatants, a subunit of the NADH-ubiquinone oxidoreductase complex, that is, an enzyme that has been described as an indicator for bacterial virulence was identified by a mass spectrometric and bioinformatic approach.

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“…In amoeba and human macrophages, bacteria such as Listeria, Rickettsia, Mycobacterium, Legionella and Chlamydia use related mechanisms to survive in cells. Amoeba and macrophages have similar phagocytic mechanisms, such as prey recognition by cell surface receptors and killing of prey by oxygen radicals (Barker and Brown, 1994).…”

Section: Interaction Between Fla and Bacteriamentioning

confidence: 99%

“…There are numerous studies (e.g. Barker and Brown, 1994;Vaerewijck et al, 2008;Thomas and Greub, 2010) that one such way is FLA acting as vehicles and fill with living bacteria, in a process called "Trojan horses". Another way is that bacteria are able to resist FLA digestion and live in trophozoites or cysts Cateau et al, 2014).…”

Section: Interaction Between Fla and Bacteriamentioning

confidence: 99%

Relationships between Free-Living Amoeba and their Intracellular Bacteria

Rubeniņa

Kirjušina

Bērziņš

et al. 2017

Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.

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An increasing number of bacteria have been described as benefiting from interaction with free-living amoeba. The most common association between free-living amoeba and microorganisms is interaction of various non-pathogenic and pathogenic bacterial species with amoeba. Various pathogenic bacterial species have capacity to resist digestion by free-living amoeba, which has been observed by many researchers. Also, several of these pathogens are able to resist digestion by macrophages. In addition, free-living amoeba have been associated with several diseases in humans. Acanthamniioeba castella is an important predator of bacteria. It is a ubiquitous organism in water, soil, and air. Attention from a public health perspective is needed by investigation of interaction of foodborne pathogens and free-living amoeba. Bacteria can use free-living amoeba as reservoirs, mediators or vehicles, an infection route, “biological gym” and evolutionary crib or interaction may result in a close endosymbiotic relationship. The purpose of this review is to describe the interaction mechanisms between free-living amoeba and common bacteria species that survive in host cells.

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Trojan Horses of the microbial world: protozoa and the survival of bacterial pathogens in the environment

Cited by 371 publications

References 11 publications

Amoeba co-culture of soil specimens recovered 33 different bacteria, including four new species and Streptococcus pneumoniae

Amoeba co-culture of soil specimens recovered 33 different bacteria, including four new species and Streptococcus pneumoniae

Proteomic aspects of Parachlamydia acanthamoebae infection in Acanthamoeba spp.

Relationships between Free-Living Amoeba and their Intracellular Bacteria

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