Co‐incubation of <i>Acanthamoeba castellanii</i> with strains of <i>Pseudomonas aeruginosa</i> alters the survival of amoeba

Am, Cengiz; Harmis, Najat; Stapleton, Fiona

doi:10.1046/j.1442-9071.2000.00291.x

Cited by 20 publications

(22 citation statements)

References 13 publications

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“…Previously, it was assumed that Pseudomonas aeruginosa and Acanthamoeba were mutually exclusive ocular pathogens, since Pseudomonas expressed amoebicidal activity in co-cultivation 36. More recently, in vitro studies have showed that Pseudomonas can actually cooperate in the pathogenesis of contact lens related AK: in fact, it increases the resistance of Acanthamoeba to contact lens disinfecting solutions and creates a biofilm on contact lenses surface that enhances amoebae retention 37 . Pseudomonas-Acanthamoeba co-infections have also been described in keratitis patients, along with the presence of Pseudomonas aeruginosa intracellularly in environmental Acanthamoebae 20, 38…”

Section: Discussionmentioning

confidence: 99%

Detection of Bacterial Endosymbionts in Clinical Acanthamoeba Isolates

et al. 2010

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Purpose-To determine the presence of four clinically relevant bacterial endosymbionts in Acanthamoeba isolates obtained from patients with Acanthamoeba keratitis (AK) and the possible contribution of endosymbionts to the pathogenesis of AK. Design-Experimental studyParticipants-Acanthamoeba isolates (N=37) recovered from cornea and contact lens paraphernalia of 23 patients with culture proven AK and 1 environmental isolate.Methods-Acanthamoeba isolates were evaluated for the presence of microbial endosymbionts belonging to the bacterial genera Legionella, Pseudomonas, Mycobacteria and Chlamydia using molecular techniques (Polymerase chain reaction and sequence analysis, fluorescent in situ hybridization) and transmission electron microscopy. Corneal toxicity and virulence of Acanthamoeba isolates with and without endosymbionts were compared using a cytopathic effect (CPE) assay of human corneal epithelial cells in vitro. Initial visual acuity (VA), location and characteristics of the infiltrate, time to detection of the infection and symptoms duration at presentation were evaluated in all patients.Main Outcome Measures-Prevalence and potential pathobiology of bacterial endosymbionts detected in Acanthamoeba isolates recovered from AK.Results-Twenty-two of the 38 (59.4%) cultures examined contained at least one bacterial endosymbiont. One isolate contained two endosymbionts, Legionella and Chlamydia, confirmed by fluorescence in situ hybridization. Corneal toxicity (CPE) was significantly higher for Acanthamoebae hosting endosymbionts compared to isolates without endosymbionts (p<0.05). Corneal pathogenic endosymbionts such as Pseudomonas and Mycobacterium enhanced Acanthamoeba CPE significantly more than Legionella (p<0.05). In the presence of bacterial endosymbionts, there was a trend toward worse initial VA (p>0.05), central location (p<0.05), Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptOphthalmology. Author manuscript; available in PMC 2011 March 1.

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Section: Discussionmentioning

confidence: 99%

Detection of Bacterial Endosymbionts in Clinical Acanthamoeba Isolates

et al. 2010

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“…associated with keratitis (Elder et al, 1994;Hay et al, 1994;Seal et al, 1996;Kim & Hahn, 1999). However, very low concentrations of PHMB (0.00005%), polyaminopropyl biguanide (0.00005%) and the QAC polyquaternium-1 (0.055-0.001%) were reported to be inactive against A. castellanii (Penley et al, 1989;Davies et al, 1990;Silvany et al, 1990;Zanetti et al, 1995;Cengiz et al, 2000), A. polyphaga (Penley et al, 1989;Davies et al, 1990;Silvany et al, 1990) and A. culbertsoni (Connor et al, 1991). Several investigations showed that the concentration of polymeric biguanides in multipurpose solutions commercially available was not cysticidal within the manufacturer's recommended contact time (Buck et al, 1998;Kilvington, 1998;Niszl & Markus, 1998).…”

Section: Activity Of Cationic Biocidesmentioning

confidence: 99%

Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality

Thomas¹,

McDonnell²,

et al. 2010

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An increasing number of microorganisms, including bacteria but also viruses and eukaryotes, have been described as benefiting from interaction with free-living amoebae (FLA). Beneficial interaction can be due to resistance to predation conferring ecological advantage, intracellular survival and/or intracellular proliferation. This review highlights the potential risk associated with amoebae by listing all known pathogenic microbial species for which growth and/or survival promotion by FLA (mainly Acanthamoeba spp.) has been demonstrated. It focuses on the susceptibility of amoebal and intra-amoebal bacteria to various categories of biocides, the known mechanisms of action of these biocides against trophozoites and cysts and the various methods used to demonstrate efficacy of treatments against FLA. Brief descriptions of FLA ecology and prevalence in domestic/institutional water systems and their intrinsic pathogenicity are also presented. The intention is to provide an informed opinion on the environmental risks associated with the presence of FLA and on the survival of cysts following biocidal treatments, while also highlighting the need to conduct research on the roles of amoebae in aquatic ecosystems.

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“…The external bacteria enhance the growth and binding of Acanthamoeba trophozoites to contact lenses, and also enhance the survival of amoeba in biocidal lens care solution (Cengiz et al, 2000). However, the mechanisms by which bacteria affect the virulence and pathogenicity of Acanthamoeba infections have yet to be thoroughly elucidated.…”

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confidence: 99%

Molecular characterization of bacterial endosymbionts of Acanthamoeba isolates from infected corneas of Korean patients

Xuan

Jeong

et al. 2007

Korean J Parasitol

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The Acanthamoeba genus is an opportunistic protozoan parasite which has adapted to live in a variety of environments, including soil, air, fresh water, ocean sediment, wild animals, and humans. Some Acanthamoeba species have been determined to induce serious human infections, including amoebic keratitis, particularly in contact lens wearers, as well as granulomatous amoebic encephalitis (GAE) in immunocompromised individuals (Marciano-Cabral and Cabral, 2003). Amebic keratitis was considered to be a relatively rare type of corneal infection during the 10 years following the first case report by Jones et al. (1975). However, the incidence of amoebic keratitis Abstract: The endosymbionts of 4 strains of Acanthamoeba (KA/E9, KA/E21, KA/E22, and KA/E23) isolated from the infected corneas of Korean patients were characterized via orcein stain, transmission electron microscopic examination, and 16S rDNA sequence analysis. Double membrane-bound, rod-shaped endosymbionts were distributed randomly throughout both the trophozoites and cysts of each of Acanthamoeba isolates. The endosymbionts of KA/E9, KA/E22, and KA/E23 were surrounded by electron-translucent areas. No lacunae-like structures were observed in the endosymbionts of KA/E21, the bacterial cell walls of which were studded with host ribosomes. Comparative analyses of the 16S rDNA sequences showed that the endosymbionts of KA/E9, KA/E22 and KA/E23 were closely related to Caedibacter caryophilus, whereas the KA/E21 endosymbiont was assigned to the CytophagaFlavobacterium-Bacteroides (CFB) phylum. In the 4 strains of Acanthamoeba, the hosts of the endosymbionts were identified as belonging to the Acanthamoeba castellanii complex, which corresponds to the T4 genotype. Acanthamoeba KA/E21 evidenced characteristics almost identical to those of KA/E6, with the exception of the existence of endosymbionts. The discovery of these endosymbionts from Acanthamoeba may prove essential to future studies focusing on interactions between the endosymbionts and the amoebic hosts.

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Co‐incubation of Acanthamoeba castellanii with strains of Pseudomonas aeruginosa alters the survival of amoeba

Cited by 20 publications

References 13 publications

Detection of Bacterial Endosymbionts in Clinical Acanthamoeba Isolates

Detection of Bacterial Endosymbionts in Clinical Acanthamoeba Isolates

Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality

Molecular characterization of bacterial endosymbionts of Acanthamoeba isolates from infected corneas of Korean patients

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