Bacterial Endosymbionts of Acanthamoeba sp.

Hall, John E.; Voelz, Herbert

doi:10.2307/3281982

Cited by 50 publications

(41 citation statements)

References 13 publications

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“…Some of these microorganisms have developed the ability to resist digestion by amoebae and are able to use these protozoa to replicate and propagate (Greub & Raoult, 2004). Furthermore, these resistant micro-organisms are able to use their host as a growth niche that is protected from external factors, including temperature and disinfectants, and are able to kill the host amoebae (Hall & Voelz, 1985). Such is the case for members of the genus Legionella, as shown by Rowbotham (1983Rowbotham ( , 1986 for Legionella pneumophila, for which several species of amoebae comprise a natural environmental reservoir.…”

mentioning

confidence: 99%

Legionella tunisiensis sp. nov. and Legionella massiliensis sp. nov., isolated from environmental water samples

Campocasso

Boughalmi

Fournous

et al. 2012

International Journal of Systematic and Evolutionary Microbiology

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Two isolates of intra-amoeba-growing bacteria, LegAT ( = DSM 24804T = CSUR P146T) and LegMT ( = DSM 24805T = CSUR P145T), were characterized on the basis of microscopic appearance, staining characteristics, axenic growth at different temperatures and the sequences of the mip, rpoB, 16S rRNA and rnpb genes, as well as the 23S–5S region. Phylogenetic analysis showed that these two isolates lay within the radius of the family Legionellaceae . Furthermore, the analysis of these genes yielded congruent data that indicated that, although strain LegMT clusters specifically with Legionella feeleii ATCC 35072T and LegAT clusters with Legionella nautarum ATCC 49596T, the divergence observed between these species was greater than that observed between other members of the family. Taken together, these results support the proposal that these two isolates represent novel members of the genus Legionella , and we propose to name them Legionella tunisiensis sp. nov. for LegMT ( = DSM 24805T = CSUR P145T) and Legionella massiliensis sp. nov. for LegAT ( = DSM 24804T = CSUR P146T).

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mentioning

confidence: 99%

Legionella tunisiensis sp. nov. and Legionella massiliensis sp. nov., isolated from environmental water samples

Campocasso

Boughalmi

Fournous

et al. 2012

International Journal of Systematic and Evolutionary Microbiology

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“…Observations on the course of infection were made with living materials by using phasecontrast microscopy and fixed preparations stained by the methods of Macchiavello (5) and Gimenez (15) were prepared as described previously (12). Grids were examined with Zeiss model DZ and Tesla model BS613 electron microscopes that were operated at 50 or 80 kV.…”

Section: Methodsmentioning

confidence: 99%

“…Although the morphology of the OIBP and the presence of peptidoglycan in its cell wall suggest that this organism is a bacterium, it has not been possible to classify it previously because of a lack of nutritional tests; the OIBP does not correspond to any bacterium described in Bergey's Manual of Determinative Bacteriology (3). Most of the many kinds of previously recognized bacteria that live within amoeba cells behave as temperate endosymbionts, and some appear to provide benefit to the hosts (1,4, [15][16][17][18]23,25). To my knowledge, the only exception is the OIBP, which causes lysis of the amoeba cells.…”

mentioning

confidence: 99%

Sarcobium lyticum gen. nov., sp. nov., an Obligate Intracellular Bacterial Parasite of Small Free-Living Amoebae

Drozański

1991

International Journal of Systematic Bacteriology

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A new genus and species of obligate intracellular bacterial parasite of small free-living amoebae is described. This bacterium causes fatal infections in amoebae belonging to the Acanthamoeba-NaegZeria group. It does not grow on any artificial substrate deprived of living amoeba cells. The entry of the bacterium into a host occurs by phagocytosis, but growth occurs in the cytoplasm, not in phagosomes. This parasite is readily distinguished from other kinds of previously recognized bacteria that live within amoeba cells on the basis of its host cell lytic activity. The bacterium is a gram-negative, short rod with tapered ends. It multiplies intracellularly by a transverse central pinching-off process. Cells are motile by means of a polar tuft of flagella. The bacterium is surrounded by a distinct multilayered cell envelope with a chemtype A,y peptidoglycan. The peptidoglycan is unique in its high content of glucosamine residues with free amino groups. The DNA base composition of this organism is 43 mol% guanine plus cytosine. The name Sarcobium Zyticum gen. nov., sp. nov. is proposed for this bacterium. The type strain of S. Zyticum is strain L2 (= PCM 2298).More than 30 years ago a new obligate intracellular bacterial parasite (OIBP) which causes fatal infections of hosts was found in a raw culture of amoebae that were freshly isolated from soil (7). This OIBP was isolated from soil from the Lublin area, Poland. In previous reports I have described the infection processes for Acanthamoeba castellanii, Hartmannella rhysodes, Hartmannella astronyxis, Mayorella palestinensis, Didasculus thorntoni, Schizopyrenus ruselli, and Naegleria gruberii, as well as 41 other unclassified amoebae isolated from soil and water reservoirs (8, 10). The OIBP did not grow on any medium when living amoebae were not present. Even a thick suspension of disrupted amoeba cells was ineffective. It has been shown that the OIBP cannot multiply if after infection the mixed culture is heated at 43°C for 10 min; this treatment is sufficient to kill trophic forms of the amoeba, but the bacterium survives. Microscopy has shown (8,11). that the parasites are readily phagocytized by amoebae and that their immediate place of residence is within phagosomes. The neighboring phagosomes fuse extensively with parasite-containing vacuoles; however, even dead bacteria evade lysosoma1 attack because the cell wall is resistant to the host's bacteriolytic enzymes. Later, living bacteria escape from phagosomes into the cytoplasm, where multiplication occurs. The final effect of the infection is total lysis of the host cells. Although the morphology of the OIBP and the presence of peptidoglycan in its cell wall suggest that this organism is a bacterium, it has not been possible to classify it previously because of a lack of nutritional tests; the OIBP does not correspond to any bacterium described in Bergey's Manual of Determinative Bacteriology (3). Most of the many kinds of previously recognized bacteria that live within amoeba cells behave as temperate endos...

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“…The presence of endosymbionts has been demonstrated in many protozoan species [57,[87][88][89][90]. The symbionts may either occur 'naturally' or may represent more recently phagocytosed organisms that have adapted to the intracellular environment.…”

Section: Naturally Occurring Bacterial Endosymbiontsmentioning

confidence: 99%

“…Several studies have speculated that endosymbionts are potential virulence factors [87,89,901. Fritsche et al [57] demonstrated intracellular bacteria in 24% of axenically grown Acanthamoeba isolates.…”

Section: Naturally Occurring Bacterial Endosymbiontsmentioning

confidence: 99%

Isolation, Identification and Increasing Importance of 'Free-Living' Amoebae Causing Human Disease

Szénási

Endo

Yagita

et al. 1998

Journal of Medical Microbiology

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Amphizoic small amoebic protozoa are capable of existing both in 'free-living' and in 'parasitic' form depending on the actual conditions. Two genera (Naegleria and Acanthamoeba) have become recognised as opportunist human parasites. Since the first description in 1965 of a lethal case of primary amoebic meningoencephalitis (PAM) caused by Naegleria, many more (mostly lethal) cases have been reported, while granulomatous amoebic encephalitis (GAE), as well as eye (keratinitis, conjunctivitis, etc.), ear, nose, skin and internal organ infections caused by Acanthamoeba have also occurred in rapidly increasing numbers. Both pathogenic and non-pathogenic species of Naegleria and Acanthamoeba are found worldwide in water, soil and dust, where they provide a potential source of infection. Successful differential diagnosis and appropriate (specific) therapy depends on precise laboratory identification of the 'free-living' amoebae. In most cases, isolation from the environment can be achieved, but identification and differentiation of the pathogenic and non-pathogenic strains is not easy. The methods presently available do not fulfil completely the requirements for specificity, sensitivity and reliability. Morphological criteria are inadequate, while thermophilic character, pH dependency and even virulence in infected mice, are not unambiguous features of pathogenicity of the different strains. More promising are molecular methods, such as restriction endonuclease digestion of whole-cell DNA or mitochondria1 DNA, as well as iso-enzyme profile analysis after iso-electric focusing and staining for acid phosphatase and propionyl esterase activity. Use of appropriate monoclonal antibodies has also yielded promising results in the differentiation of human pathogenic and non-pathogenic strains. However, quicker, simpler, more specific and reliable methods are still highly desirable. The significance of endosymbiosis (especially with Legionella strains) is not well understood. The results of a systematic survey in Hungary for the isolation and identification of 'free-living' amoebae, including an investigation of the Hungarian amoebic fauna, the isolation of possibly pathogenic Naegleria strains and of some Acanthamoeba strains from eye diseases, as well as the finding of a case of endosymbiosis, are also reported here.

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Bacterial Endosymbionts of Acanthamoeba sp.

Cited by 50 publications

References 13 publications

Legionella tunisiensis sp. nov. and Legionella massiliensis sp. nov., isolated from environmental water samples

Legionella tunisiensis sp. nov. and Legionella massiliensis sp. nov., isolated from environmental water samples

Sarcobium lyticum gen. nov., sp. nov., an Obligate Intracellular Bacterial Parasite of Small Free-Living Amoebae

Isolation, Identification and Increasing Importance of 'Free-Living' Amoebae Causing Human Disease

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