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Parasitology Research Feb 2012Acanthamoeba keratitis is a painful corneal infection and difficult to treat because no sufficiently efficient drug has yet been available. The aim of the study... (Comparative Study)
Comparative Study
Acanthamoeba keratitis is a painful corneal infection and difficult to treat because no sufficiently efficient drug has yet been available. The aim of the study therefore was to assess the therapeutic potential of miltefosine on Acanthamoeba keratitis-infected hamster eyes. The cornea of hamsters were infected with Acanthamoeba hatchetti, a human corneal isolate. On the fifth day, all the cornea were microscopically examined in order to determine the degree of infections (G, from 0 to 3). Four groups were then prepared: miltefosine (160 μM); 0.1% propamidine isetionate plus 0.02% polyhexnide; infected control (0.05% ethanol in PBS) and a non-infected control (0.05% ethanol in PBS) groups. The treatment was continued for 28 days. After the treatment, the cornea were excised and used for Acanthamoeba culture to investigate the presence of Acanthamoeba growth. Miltefosine treatment yielded much higher cure scores than propamidine isetionate plus polyhexanide. On the last day of treatment, 85% of the miltefosine-treated eyes were graded as G0; no changes were observed in the uninfected control group eyes; G3 eyes showed only a partial improvement. Furthermore, no Acanthamoeba cells could be recovered from the miltefosine-treated eye samples. Miltefosine appeared to hold necessary therapeutic properties for the treatment of Acanthamoeba keratitis.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Administration, Topical; Animals; Antiprotozoal Agents; Benzamidines; Biguanides; Cricetinae; Disease Models, Animal; Humans; Male; Mesocricetus; Phosphorylcholine; Treatment Outcome
PubMed: 21748351
DOI: 10.1007/s00436-011-2515-0 -
Isolation and characterization of Acanthamoeba spp. from air-conditioners in Kuala Lumpur, Malaysia.Acta Tropica Jan 2011During a study on the quality of the indoor environment, Acanthamoeba spp. were detected in 20 out of 87 dust samples collected from air-conditioners installed in a...
During a study on the quality of the indoor environment, Acanthamoeba spp. were detected in 20 out of 87 dust samples collected from air-conditioners installed in a four-story campus building located in Kuala Lumpur, Malaysia. Twenty-one cloned Acanthamoeba isolates designated as IMU1 to IMU21 were established from the positive primary cultures. Five species were identified from the 16 isolates according to the morphological criteria of Pussard and Pons; i.e. A. castellanii, A. culbertsoni, A. griffini, A. hatchetti and A. polyphaga. Species identities for the remaining five isolates (IMU4, IMU5, IMU15, IMU20 and IMU21), however, could not be determined morphologically. At genotypic characterization, these isolates were placed into T3 (IMU14); T5 (IMU16 and IMU17) and T4 (all the remaining isolates). To predict the potential pathogenicity of these Acanthamoeba isolates, thermo- and osmotolerance tests were employed; many isolates were predicted as potential human pathogens based on the outcome of these tests. This is the first time potentially pathogenic Acanthamoeba have been isolated from air-conditioners in Malaysia.
Topics: Acanthamoeba; Air Conditioning; Cell Survival; Cluster Analysis; DNA, Protozoan; DNA, Ribosomal; Dust; Environmental Microbiology; Genes, rRNA; Hot Temperature; Humans; Malaysia; Microscopy; Molecular Sequence Data; Osmotic Pressure; Phylogeny; RNA, Protozoan; RNA, Ribosomal, 18S; Sequence Analysis, DNA
PubMed: 20858455
DOI: 10.1016/j.actatropica.2010.09.004 -
Journal of Clinical Microbiology Jul 2009Acanthamoebae are free-living amoebae found in the environment, including soil, freshwater, brackish water, seawater, hot tubs, and Jacuzzis. Acanthamoeba species can...
Acanthamoebae are free-living amoebae found in the environment, including soil, freshwater, brackish water, seawater, hot tubs, and Jacuzzis. Acanthamoeba species can cause keratitis, a painful vision-threatening infection of the cornea, and fatal granulomatous encephalitis in humans. More than 20 species of Acanthamoeba belonging to morphological groups I, II, and III distributed in 15 genotypes have been described. Among these, Acanthamoeba castellanii, A. polyphaga, and A. hatchetti are frequently identified as causing Acanthamoeba keratitis (AK). Improper contact lens care and contact with nonsterile water while wearing contact lenses are known risk factors for AK. During a recent multistate outbreak, AK was found to be associated with the use of Advanced Medical Optics Complete MoisturePlus multipurpose contact lens solution, which was hypothesized to have had insufficient anti-Acanthamoeba activity. As part of the investigation of that outbreak, we compared the efficacies of 11 different contact lens solutions against cysts of A. castellanii, A. polyphaga, and A. hatchetti (the isolates of all species were genotype T4), which were isolated in 2007 from specimens obtained during the outbreak investigation. The data, generated with A. castellanii, A. polyphaga, and A. hatchetti cysts, suggest that the two contact lens solutions containing hydrogen peroxide were the only solutions that showed any disinfection ability, with 0% and 66% growth, respectively, being detected with A. castellanii and 0% and 33% growth, respectively, being detected with A. polyphaga. There was no statistically significant difference in disinfection efficacy between the 11 solutions for A. hatchetti.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Animals; Antiprotozoal Agents; Contact Lens Solutions; Disinfection; Humans
PubMed: 19403771
DOI: 10.1128/JCM.00575-09 -
Turkiye Parazitolojii Dergisi 2007Acanthamoeba spp. are among the most prevalent protozoa found in the environment. The species of this genus are the causative agents of granulomatous amebic encephalitis...
Acanthamoeba spp. are among the most prevalent protozoa found in the environment. The species of this genus are the causative agents of granulomatous amebic encephalitis (GAE), a fatal disease of the central nervous system (CNS), and amebic keratitis (AK), a painful sight-threatening disease of the eye. In this study we have used two species of Acanthamoeba, Acanthamoeba castellanii and A. hatchetti, both were obtained from Vienna, Austria. They were cultivated on non-nutritious agar seeded with Escherichia coli and PPYG (protease peptone-yeast extract-glucose) medium. Our aim was to concentrate on three points in relation to the trophozoites and cysts stages of these species as follows: (i) to observe their morphology, (ii). to confirm our previous observation of a canal between two trophozoites. The bridge-like connection between these trophozoites greatly resembled the one that can be observed in conjugation during an exchange of genetic material. Two tro-phozoites with a bridge-like extension between them keep their position for at least 200 minutes. (iii). to detect the reactions of trophozoites to various stains. According to our findings in regard to these three points: (i). trophozoites with more than one nucleus are often seen in axenic cultures. (ii). This resembles a type of conjugation with a transfer of genetic material between two trophozoites. Certainly, this needs further investigation using more sophisticated methods. (iii). trophozoites equally stained well with Heidenhain's iron haematoxylin, Giemsa, PAS, Masson Trichrome, and Toludin-O stains. However, our results with reticulin, PAP, Van Gison, Musicarmine and Orsein stains were not satisfactory.
Topics: Acanthamoeba; Amebiasis; Animals; Coloring Agents; Conjugation, Genetic; Staining and Labeling; Trophozoites
PubMed: 17471404
DOI: No ID Found -
The Korean Journal of Parasitology Jun 2006Genetic diversity of 18 Acanthamoeba isolates from ocean sediments was evaluated by comparing mitochondrial (mt) DNA RFLP, 18S rDNA sequences and by examining their...
Genetic diversity of 18 Acanthamoeba isolates from ocean sediments was evaluated by comparing mitochondrial (mt) DNA RFLP, 18S rDNA sequences and by examining their cytopathic effects on human corneal epithelial cells versus reference strains. All isolates belonged to morphologic group II. Total of 16 restriction phenotypes of mtDNA from 18 isolates demonstrated the genetic diversity of Acanthamoeba in ocean sediments. Phylogenetic analysis using 18s rDNA sequences revealed that the 18 isolates were distinct from morphological groups I and III. Fifteen isolates showed close relatedness with 17 clinical isolates and A. castellanii Castellani and formed a lineage equivalent to T4 genotype of Byers group. Two reference strains from ocean sediment, A. hatchetti BH-2 and A. griffini S-7 clustered unequivocally with these 15 isolates. Diversity among isolates was also evident from their cytopathic effects on human corneal cells. This is the first time describing Acanthamoeba diversity in ocean sediments in Korea.
Topics: Acanthamoeba; Animals; DNA, Mitochondrial; Epithelial Cells; Epithelium, Corneal; Genetic Variation; Geologic Sediments; Humans; Oceans and Seas; Phylogeny; RNA, Ribosomal, 18S
PubMed: 16809959
DOI: 10.3347/kjp.2006.44.2.117 -
The British Journal of Ophthalmology Feb 2002Contact lens cases contaminated with Acanthamoeba are a major risk factor for an infection of the eye. In this study the anti-Acanthamoeba activity of three different... (Comparative Study)
Comparative Study
BACKGROUND/AIM
Contact lens cases contaminated with Acanthamoeba are a major risk factor for an infection of the eye. In this study the anti-Acanthamoeba activity of three different contact lens storage solutions was tested.
METHODS
A new multipurpose contact lens storage solution (Meni Care Plus) and a two step (Titmus H(2)O(2)) and one step (Oxysept Comfort) hydrogen peroxide system were tested for their effects on trophozoites and cysts of three different Acanthamoeba species: A castellanii, A hatchetti, and A lenticulata.
RESULTS
After a soaking time of 8 hours (overnight soaking of contact lenses) the Titmus H(2)O(2) 0.6% solution showed very good amoebicidal effects, while Oxysept Comfort 3% H(2)O(2) could not effectively destroy the cysts of any of the three tested species. Viable cysts of the species A lenticulata and A hatchetti were still present after exposure to Meni Care Plus (0.0005% PHMB) for 8 hours.
CONCLUSION
Not all of the three tested contact lens storage solutions have sufficient amoebicidal effects. The two step peroxide system Titmus H(2)O(2) is a very effective disinfectant contact lens solution in order to avoid a possible Acanthamoeba infection of the eye.
Topics: Acanthamoeba; Animals; Biguanides; Contact Lens Solutions; Disinfectants; Disinfection; Equipment Contamination; Humans; Hydrogen Peroxide
PubMed: 11815336
DOI: 10.1136/bjo.86.2.144 -
Cornea Jul 2001Microbially contaminated contact lens cases are a predisposing risk factor for Acanthamoeba keratitis. Several findings have shown that microwave irradiation kills the...
PURPOSE
Microbially contaminated contact lens cases are a predisposing risk factor for Acanthamoeba keratitis. Several findings have shown that microwave irradiation kills the six Food and Drug Administration test challenge microorganisms. We aimed to determine what effect microwave irradiation has on Acanthamoeba trophozoites and cysts.
METHODS
Different types of contact lens cases were contaminated with trophozoites and cysts of three different Acanthamoeba species (A. comandoni, A. castellanii, A. hatchetti) and were exposed to microwave irradiation for 3, 5, and 8 minutes, respectively.
RESULTS
Trophozoites, as well as cysts of the different Acanthamoeba strains, were effectively killed, even by only 3 minutes of microwave irradiation, and there were no negative effects of irradiation on the contact lens cases themselves.
CONCLUSION
We demonstrate that microwave treatment is a very effective, easy, and cheap method to keep contact lens cases free of Acanthamoeba, thus considerably reducing the risk of an Acanthamoeba keratitis.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Animals; Contact Lenses; Disinfection; Humans; Microwaves; Product Packaging
PubMed: 11413399
DOI: 10.1097/00003226-200107000-00005 -
Journal of Clinical Microbiology Nov 2000Eighteen cases of Acanthamoeba-associated keratitis among contact lens wearers seen at the Department of Ophthalmology, Karl-Franzens-University, Graz, Austria, between...
Eighteen cases of Acanthamoeba-associated keratitis among contact lens wearers seen at the Department of Ophthalmology, Karl-Franzens-University, Graz, Austria, between 1996 and 1999 are reviewed. The amoebae were proven to be the causative agents in three patients. The aim of our study was to discriminate between clinically relevant and nonrelevant isolates and to assess the relatedness of the isolates to published strains. Altogether, 20 strains of free-living amoebae, including 15 Acanthamoeba strains, 3 Vahlkampfia strains, and 2 Hartmannella strains, were isolated from clinical specimens. The virulent Acanthamoeba strains were identified as A. polyphaga and two strains of A. hatchetti. To our knowledge this is the first determination of keratitis-causing Acanthamoeba strains in Austria. Clinically relevant isolates differed markedly from nonrelevant isolates with respect to their physiological properties. 18S ribosomal DNA sequence types were determined for the three physiologically most-divergent strains including one of the keratitis-causing strains. This highly virulent strain exhibited sequence type T6, a sequence type not previously associated with keratitis. Sequence data indicate that Acanthamoeba strains causing keratitis as well as nonpathogenic strains of Acanthamoeba in Austria are most closely related to published strains from other parts of the world. Moreover, the results of our study support the assumption that pathogenicity in Acanthamoeba is a distinct capability of certain strains and not dependent on appropriate conditions for the establishment of an infection.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Adolescent; Adult; Animals; Contact Lenses; DNA, Protozoan; DNA, Ribosomal; Female; Humans; Male; Middle Aged; Molecular Sequence Data; Polymerase Chain Reaction; RNA, Ribosomal, 18S; Sequence Analysis, DNA; Virulence
PubMed: 11060047
DOI: 10.1128/JCM.38.11.3932-3936.2000 -
The Korean Journal of Parasitology Jun 2000In order to observe the cytotoxicity of Acanthamoeba spp., which were isolated from contact lens containers as ethiological agents for the probable amoebic keratitis in...
In order to observe the cytotoxicity of Acanthamoeba spp., which were isolated from contact lens containers as ethiological agents for the probable amoebic keratitis in Korea, the crystal violet staining method and LDH release assay were carried out. In the crystal violet staining method, among eight contact lens container isolates, isolate 3 (Acanthamoeba KA/LS5) showed 83.6% and 81.8% of cytotoxicity, and isolate 7 (Acanthamoeba KA/LS37) showed 28.2% and 25.1% of cytotoxicity, in 1 mg/ml and 0.5 mg/ml lysate treatments, respectively. Acanthamoeba culbertsoni and A. healyi showed 84.0% and 82.8% of cytotoxicity. Similar results were observed in A. castellanii and A. hatchetti which showed 83.6% and 75.5% of cytotoxicity. Acanthamoeba royreba and A. polyphaga showed 9.0% and 1.7% of cytotoxicity. In the LDH release assay, isolate 3 (20.4%) showed higher cytotoxicity than other isolates in 1 mg/ml lysate treatment. The results provide that at least isolate 3 has the cytotoxic effect against CHO cells and seems to be the pathogenic strain.
Topics: Acanthamoeba; Animals; CHO Cells; Cell Survival; Contact Lenses; Cricetinae; Equipment Contamination; Gentian Violet; Humans; Korea; L-Lactate Dehydrogenase; Staining and Labeling
PubMed: 10905072
DOI: 10.3347/kjp.2000.38.2.99 -
The Korean Journal of Parasitology Dec 1999In order to refer to the basic information regarding the identification of isolates obtained from a contact lens container in Korea, the isoelectric focusing gel...
In order to refer to the basic information regarding the identification of isolates obtained from a contact lens container in Korea, the isoelectric focusing gel electrophoresis was employed to compare the isoenzyme band patterns among Acanthamoeba spp. including eight isolates and the simple pairwise dissimilarity analysis was carried out. For an alkaline phosphate development, isolate 7 and Acanthamoeba polyphaga showed homologous band patterns, and isolates 1, 2, and 3 showed the same patterns. For lactate dehydrogenase, similar patterns were observed in isolates 2 and 3. Isolates 3 and 5 showed homologous band patterns for malate dehydrogenase and glucose phosphate isomerase. For hexokinase, isolates 4, 7, and A, hatchetti showed the same band patterns. In others, a considerable number of interstrain polymorphisms was observed in nine isoenzyme band patterns. In Acanthamoeba group II, genetic distances among isolates 1, 2, 3, 4, and 5 ranged from 0.104 to 0.200. In comparison to A. castellanii, A. hatchetti, and A. polyphaga, genetic distances of isolates 7 and 8 were 0.254 and 0.219, respectively. In Acanthamoeba group III, including A. culbertsoni, A. healyi, and A. royreba, isolate 6 had genetic distances which ranged from 0.314 to 0.336. Finally, when comparing to the six reference Acanthamoeba, it was possible to classify isolates 1, 2, 3, 4, and 5, as genetically close-related species and as independent species group. Furthermore, isolates 6, 7 and 8 were identified as independent species as well.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Animals; Contact Lenses; Humans; Isoelectric Focusing; Isoenzymes; Korea; Phylogeny
PubMed: 10634038
DOI: 10.3347/kjp.1999.37.4.229