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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 -
Journal of Ophthalmic Nursing &... 19931. Acanthamoeba keratitis is an uncommon but increasingly prevalent infection with the potential to cause severe ocular damage. Acanthamoeba is a nonflagellated...
1. Acanthamoeba keratitis is an uncommon but increasingly prevalent infection with the potential to cause severe ocular damage. Acanthamoeba is a nonflagellated free-living amoeba that is ubiquitous in the environment. The most common type is A castellani, but A polyphagia, A rhysodes, A culbertson, and A hatchetti have been isolated from infected eyes. 2. Clinical features include foreign body sensation, blurred vision, tearing, and photophobia. There is minimal pain in the early stages of infection, but severe pain is a manifestation of the advanced stages of the disease. 3. The incidence of Acanthamoeba keratitis appears to be decreasing because of increased awareness, but education emphasizing proper lens sterilization is essential and should be carried out when contact lenses are first dispensed.
Topics: Acanthamoeba Keratitis; Humans; Primary Prevention; Prognosis
PubMed: 8158668
DOI: No ID Found -
European Journal of Protistology Oct 2016Acanthamoebae feed on bacteria but are also frequent hosts of bacterial symbionts. Here, we describe the stable co-occurrence of two symbionts, one affiliated to the...
Acanthamoebae feed on bacteria but are also frequent hosts of bacterial symbionts. Here, we describe the stable co-occurrence of two symbionts, one affiliated to the genus Parachlamydia and the other to the candidate genus Paracaedibacter (Alphaproteobacteria), within a clinical isolate of Acanthamoeba hatchetti genotype T4. We performed fluorescence in situ hybridization (FISH) and transmission electron microscopy (TEM) to describe this symbiosis. Our study adds to other reports of simultaneous co-occurrence of two symbionts within one Acanthamoeba cell.
Topics: Acanthamoeba; Alphaproteobacteria; Amebiasis; Chlamydiales; Humans; In Situ Hybridization, Fluorescence; Keratitis; Microscopy, Electron, Transmission; Phylogeny; RNA, Ribosomal, 16S; Symbiosis
PubMed: 27344110
DOI: 10.1016/j.ejop.2016.04.002 -
Parasitology Research Feb 2013Acanthamoeba keratitis (AK) is a potentially devastating and sight-threatening infection of the cornea caused by the ubiquitous free-living amoebae, Acanthamoeba...
Acanthamoeba keratitis (AK) is a potentially devastating and sight-threatening infection of the cornea caused by the ubiquitous free-living amoebae, Acanthamoeba species. Its eradication is difficult because the amoebas encyst, making it highly resistant to anti-amoebic drugs. Acriflavine neutral (ACF) has been used for treatment of microbial infections for humans and fishes. The aim of our study was to evaluate the time-dependent cytotoxicities of ACF against Acanthamoeba spp. Trophozoites and cysts of three different strains (strain PAT06 Acanthamoeba castellanii, strain 2HH Acanthamoeba hatchetti, and strain 11DS A. hatchetti) of Acanthamoeba spp. were tested. All strains had been isolated from patients suffering from a severe AK. The effects of the ACF with the concentrations ranging from 15 to 500 mg mL(-1) on the cytotoxicity of Acanthamoeba strains were examined. ACF showed a time- and dose-dependent amebicidal action on the trophozoites and cysts. Pat06 (A. castellanii) was the most resistant, while strain 11DS (A. hatchetti) was the most sensitive. As a result, ACF could be concluded as a new agent for the treatment of Acanthamoeba infections. On the other hand, it still needs to be further evaluated by in vivo test systems to confirm the efficiency of its biological effect.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Acriflavine; Antiprotozoal Agents; Cell Survival; Humans; Parasitic Sensitivity Tests
PubMed: 23052789
DOI: 10.1007/s00436-012-3163-8 -
Journal of Clinical Microbiology Aug 2014A case of amoebic placentitis in a mare from eastern Australia was diagnosed postpartum by histopathological examination of the placenta. The identity of the etiological...
A case of amoebic placentitis in a mare from eastern Australia was diagnosed postpartum by histopathological examination of the placenta. The identity of the etiological agent was confirmed as Acanthamoeba hatchetti by use of diversity profiling based on a next-generation sequencing approach.
Topics: Acanthamoeba; Amebiasis; Animals; Australia; DNA, Protozoan; Female; High-Throughput Nucleotide Sequencing; Horse Diseases; Horses; Molecular Sequence Data; Placenta Diseases; Pregnancy; Pregnancy Complications, Parasitic
PubMed: 24829227
DOI: 10.1128/JCM.01071-14 -
Journal of Medical Microbiology Jan 2020keratitis is a sight-threatening corneal infection that is commonly reported among contact lens users and those suffering from corneal trauma. The prevalence of...
keratitis is a sight-threatening corneal infection that is commonly reported among contact lens users and those suffering from corneal trauma. The prevalence of species or genotypes in causing keratitis infection is not well known. This study was conducted to identify and genotype isolates from keratitis patients, targeting the ribosomal nuclear subunit () region, and describe the associated clinical presentation and treatment outcome. Thirty culture-confirmed patients with keratitis, identified in a tertiary eye care centre in South India during the period from December 2016 to December 2018, were included in this study. The data collected from patient records include demographic details, history of illness, mode of trauma, treatment history and follow-up status. The genotype and species were identified based on the sequence and phylogenetic tree analysis. was the most predominant keratitis-causing species, followed by and . Three major genotypes were identified (T4, T11 and T12), with the T4 genotype being the most predominant, with four subclusters, i.e. T4A, T4B, T4D and T4E. This is the first report on corneal infection by the T11 genotype and the T12 genotype. No significant correlation was observed between the clinical outcomes of corneal disease and the genotypes or species. genotyping is very effective in identifying the species and genotype in keratitis. Genotyping of spp. will help to advance our understanding of genotype-specific pathogenesis and geographical distribution.
Topics: Acanthamoeba Keratitis; Acanthamoeba castellanii; Genes, rRNA; Genotype; Genotyping Techniques; Humans; India; Phylogeny; Tertiary Care Centers
PubMed: 31846414
DOI: 10.1099/jmm.0.001121 -
Journal Francais D'ophtalmologie Apr 2020Acanthamoeba keratitis due to a genus of free-living amoebae is a severe corneal infection. Treatment of this disease is based on the combined use of antiseptics and...
Acanthamoeba keratitis due to a genus of free-living amoebae is a severe corneal infection. Treatment of this disease is based on the combined use of antiseptics and other drugs, including azoles. We tested isavuconazole, the latest marketed azole, in vitro, against A. castellanii, A. lenticulata and A. hatchetti. Our results show that isavuconazole presents slight amoebistatic activity against A. castellanii trophozoites but no cysticidal activity. Isavuconazole could be used only in association for management of AK due to A. castellanii.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Acanthamoeba castellanii; Animals; Dose-Response Relationship, Drug; Humans; Nitriles; Parasite Encystment; Parasitic Sensitivity Tests; Pyridines; Triazoles; Trophozoites
PubMed: 32151474
DOI: 10.1016/j.jfo.2019.06.014 -
Science (New York, N.Y.) Jun 1977Acanthamoeba culbertsoni was isolated from a sewage-spoil dump site near Ambrose Light, New York Bight. A second species, Acanthamoeba hatchetti, n. sp., was isolated...
Acanthamoeba culbertsoni was isolated from a sewage-spoil dump site near Ambrose Light, New York Bight. A second species, Acanthamoeba hatchetti, n. sp., was isolated from Brewerton Channel, Baltimore Harbor, Maryland. Both species killed laboratory mice after infection by the intranasal route.
Topics: Amebiasis; Amoeba; Animals; Body Weight; Brain; Lung; Mice; Refuse Disposal; Seawater; Soil Microbiology; Water Microbiology
PubMed: 867031
DOI: 10.1126/science.867031 -
Acta Tropica Apr 2014The occurrence of Acanthamoeba was investigated from 21 main reservoirs of Taiwan with 12 (57.1%) testing positive. Analysis of the 18S rRNA gene PCR product was...
The occurrence of Acanthamoeba was investigated from 21 main reservoirs of Taiwan with 12 (57.1%) testing positive. Analysis of the 18S rRNA gene PCR product was performed in order to identify the Acanthamoeba isolates. Acanthamoeba spp. concentrations were determined according to TaqMan real-time qPCR. Acanthamoeba genotypes of all isolates were identified T4. The species were categorized to Acanthamoeba culbertsoni, Acanthamoeba polyphaga, Acanthamoeba castellanii and Acanthamoeba hatchetti. The concentration of Acanthamoeba spp. in detected positive reservoir water samples was in the range of 3.0-1.8 × 10(3) cells/L. These results highlight the importance of Acanthamoeba in reservoirs of potential pathogens and its possible role in the spread of bacterial genera with interest in public and environmental health.
Topics: Acanthamoeba castellanii; DNA, Protozoan; Genotype; Humans; Molecular Sequence Data; RNA, Ribosomal, 18S; Real-Time Polymerase Chain Reaction; Sequence Analysis, DNA; Taiwan; Water
PubMed: 24388954
DOI: 10.1016/j.actatropica.2013.12.020 -
The Science of the Total Environment Sep 2022Cryptosporidium is the leading agent of waterborne parasitic protozoan outbreaks and is the second leading cause of infant mortality due to diarrhoea worldwide....
Cryptosporidium is the leading agent of waterborne parasitic protozoan outbreaks and is the second leading cause of infant mortality due to diarrhoea worldwide. Acanthamoeba spp. causes Acanthamoeba keratitis (AK) and a life-threatening condition known as granulomatous amoebic encephalitis (GAE). The present study aimed to assess the water quality of an indigenous and a rural community for waterborne parasitic protozoan contamination. Aquatic samples (n = 22) were processed by filtration of 500 mL portion through a 1.2 μm pore size glass microfiber filter and eluted for light microscopy, culture in non-nutrient agar, and PCR analysis. Overall, 36% (8/22) of the investigated aquatic samples were positive for either Cryptosporidium spp. oocysts (13%; 3/22) or Acanthamoeba spp., (36%; 8/22) or both (13%; 3/22). Cryptosporidium spp. oocysts were detected in 27% (3/11) of wet season samples only while Acanthamoeba spp. were detected in 18% (2/11) and 55% (6/11) of wet and dry season samples, respectively. Subsequently, molecular detection for Acanthamoeba species identified A. lenticulata and A. hatchetti with 98-99% BLAST similarity. This is the first report on the simultaneous contamination of Cryptosporidium and Acanthamoeba in well water sources in East-Southeast Asia, the first detection of Acanthamoeba spp. in biofilms in the Philippines, and the longest viability demonstrated for A. lenticulata in two-year-old water samples stored at room temperature.
Topics: Acanthamoeba; Animals; Biofilms; Child, Preschool; Cryptosporidiosis; Cryptosporidium; Humans; Oocysts; Philippines
PubMed: 35533862
DOI: 10.1016/j.scitotenv.2022.155752