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The Korean Journal of Parasitology Oct 2009After morphological grouping of Acanthamoeba by Pussard and Pons, phylogeny of the genus has been always a big topic to the researchers. Because of the variability of... (Review)
Review
After morphological grouping of Acanthamoeba by Pussard and Pons, phylogeny of the genus has been always a big topic to the researchers. Because of the variability of morphological characteristics, unchangeable and stable characters have been investigated for phylogenic criteria. Isoenzyme and mitochondrial DNA RFLP (Mt DNA RFLP) analyses revealed different patterns among strains assigned to a same species. Therefore, these characteristics would be considered as tools for strain discrimination than species identification. The most recently developed and the most promising method is the sequence analysis of 18s ribosomal RNA coding DNA (18s rDNA). The phylogenic tree based on comparison of 18s rDNA sequences distinguished the 3 morphological groups of Acanthamoeba and divided them into 12 unique sequence types (T1-T12 genotypes). Most clinical and environmental isolates belonged to the morphological group II and the genotype T4. In the Republic of Korea, 2 strains of Acanthamoeba, YM-2 and YM-3, were first isolated from the environment in 1974. However, phylogenic identification of Korean Acanthamoeba isolates from human infections or the environment were tried from the late 1990s. By RFLP analysis or total sequence analysis of 18s rDNA revealed that almost all clinical isolates including the one from a suspicious granulomatous amebic encephalitis patient belonged to the genotype T4. A large number of environmental isolates from contact lens storage cases, tapped water, and ocean sediments also belonged to the genotype T4. Almost identical strain characteristics, such as Mt DNA RFLP pattern of environmental isolates, with the clinical isolates could make a simple conclusion that most environmental isolates might be a potential keratopathogen.
Topics: Acanthamoeba; Amebiasis; DNA, Protozoan; DNA, Ribosomal; Humans; Molecular Sequence Data; Phylogeny; Soil; Water
PubMed: 19885332
DOI: 10.3347/kjp.2009.47.S.S21 -
Japanese Journal of Infectious Diseases May 2021Acanthamoeba are free-living amoebae that cause granulomatous amoebic encephalitis and keratitis. In this study, we aimed to isolate and identify Acanthamoeba from air...
Acanthamoeba are free-living amoebae that cause granulomatous amoebic encephalitis and keratitis. In this study, we aimed to isolate and identify Acanthamoeba from air conditioning systems using in vitro cell culture and polymerase chain reaction assays. We also estimated the pathogenicity of the isolates by measuring their thermotolerance and studying mice models inoculated with these isolates. Of the 80 dust samples acquired, 41 (51.25%) were found to be positive for Acanthamoeba spp. using in vitro cell culture and the results were validated using PCR. Out of these 41 samples, 27 (65.9%) were thermotolerant and 16 (39%) samples could infect mice and cause histopathological effects. Highly pathogenic Acanthamoeba isolates were characterized by their thermotolerance and the ability to disseminate in all organs after infection, causing early death of infected animals. Our study thus validated the presence of pathogenic isolates of Acanthamoeba in air conditioners that may be potentially infectious to humans.
Topics: Acanthamoeba; Air Conditioning; Amebiasis; Animals; Disease Models, Animal; Dust; Egypt; Equipment Contamination; Humans; Mice; Polymerase Chain Reaction; RNA, Ribosomal, 18S
PubMed: 32999181
DOI: 10.7883/yoken.JJID.2020.049 -
Parasitology Research Dec 2022Reptiles are frequently kept as pet animals. They are considered as important reservoirs of protozoa with veterinary-medical significance. At a reptile farm in Ireland,...
Reptiles are frequently kept as pet animals. They are considered as important reservoirs of protozoa with veterinary-medical significance. At a reptile farm in Ireland, fecal samples were collected from 98 captive reptiles, representing 43 species of three orders (Squamata, Testudines, and Crocodylia). After DNA extraction, all samples were screened by conventional PCRs, targeting the ribosomal small subunit (SSU) RNA and alpha-tubulin genes of trichomonads and SSU RNA gene of Acanthamoeba spp. One leopard gecko (Eublepharis macularius) was positive for a not yet reported species/genotype of the genus Monocercomonas, different from M. colubrorum. Various Acanthamoeba genotypes were detected in six reptilian species, i.e., Acanthamoeba genotype T11 in Eunectes notaeus and Heloderma suspectum/horridum; genotype T4 in Varanus exanthematicus, Chlamydosaurus kingii, and Macrochelys temminckii; and the genotype T13 in Iguana iguana. Some of these amoeba species might have clinicopathological significance in both humans and animals. Our findings highlight the importance to monitor pathogenic protozoa in pet as well as wildlife reptiles, as a source of possible infection for animals and humans living nearby.
Topics: Humans; Animals; Acanthamoeba; Amoeba; Reptiles; Genotype; Feces; Trichomonadida; RNA
PubMed: 36184660
DOI: 10.1007/s00436-022-07677-3 -
Experimental Parasitology Jul 2013Species of Acanthamoeba are frequently isolated from distinct environmental sources such as water, soil, dust and air. They are responsible to cause infections and...
Species of Acanthamoeba are frequently isolated from distinct environmental sources such as water, soil, dust and air. They are responsible to cause infections and disease in humans and animals. In addition, Acanthamoeba sp. are considered an important reservoir of bacteria, virus and fungi, which act as "Trojan horses" to protect these microorganisms of harsh environmental conditions. In this study, nine Acanthamoeba isolates from bromeliads phylloplane were identified based on the morphology of cyst and trophozoite forms. The genotype level was accessed by the sequence analysis of Acanthamoeba small-subunit rRNA gene. Genotypic characterization grouped five isolates in the genotype T2/T6, three in the T4 genotype and one in the genotype T16. The results obtained indicate that the genotype T2/T6 is common on phylloplane. To predict the pathogenic potential of the Acanthamoeba isolates, thermo and osmotolerance assays were employed, although all isolates were capable of surviving at temperatures of 37°C, other tests will be conducted in the future to determine the potential pathogenic of the isolates. Altogether, our results revealed the importance of the presence of Acanthamoeba associated with bromeliads in Rio Grande do Sul, Brazil, and the necessity for further studies to determine the environmental distribution and the role of these species.
Topics: Acanthamoeba; Base Sequence; Brazil; Bromeliaceae; Genotype; Genotyping Techniques; Molecular Sequence Data; Osmolar Concentration; Phylogeny; Plant Leaves; RNA, Ribosomal, 18S; Sequence Alignment; Temperature; Virulence
PubMed: 23562883
DOI: 10.1016/j.exppara.2013.03.028 -
Veterinary Journal (London, England :... Aug 2021Pathogenic free-living amoebae, most notably Acanthamoeba spp., are important pathogens of the human cornea. The importance of infection with free-living amoebae in cats...
Pathogenic free-living amoebae, most notably Acanthamoeba spp., are important pathogens of the human cornea. The importance of infection with free-living amoebae in cats with keratitis is currently unclear. The aim of this study was to determine the frequency of amoeba detection in corneas of cats with naturally-acquired keratitis and in the ocular surface microflora of cats without ocular disease. Clinical ophthalmic and in vivo corneal confocal microscopic examinations were performed on 60 cats with keratitis. Corneal scrapings were analyzed by amoeba culture; cytological evaluation; and Acanthamoeba, Hartmannella, and Vahlkampfia PCR assays. Following ophthalmic examination, conjunctival specimens collected from 60 cats without clinically apparent ocular disease were analyzed similarly. In one cat with ulcerative keratitis, amoeba cysts and trophozoites were detected by in vivo corneal confocal microscopy; an Acanthamoeba sp. was isolated from corneal specimens and detected by Acanthamoeba PCR assay; and suppurative corneal inflammation was present cytologically. An Acanthamoeba sp. was isolated from conjunctival specimens from one cat without clinically apparent ocular disease, but with suppurative inflammation demonstrated cytologically. Both Acanthamoeba isolates belonged to the T4 genotype. Naegleria-like amoebae were isolated in samples from two cats with keratitis and seven cats without clinical ocular disease, but amoebae were not detected by the other assays in these samples. Amoeba detection by culture was significantly (P = 0.01) associated with cytologically diagnosed corneoconjunctival inflammation. This study identified naturally-acquired Acanthamoeba keratitis in cats. Detection of Naegleria-like amoebae in samples from cats with and without keratitis is of uncertain pathological significance.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Amoeba; Animals; Cat Diseases; Cats; Cornea; Female; Keratitis; Male
PubMed: 34182073
DOI: 10.1016/j.tvjl.2021.105712 -
Genes Aug 2019The epithelium represents the first and most extensive line of defence against pathogens, toxins and pollutant agents in humans. In general, pathogens have developed... (Review)
Review
The epithelium represents the first and most extensive line of defence against pathogens, toxins and pollutant agents in humans. In general, pathogens have developed strategies to overcome this barrier and use it as an entrance to the organism. , and spp. are amoebae mainly responsible for intestinal dysentery, meningoencephalitis and keratitis, respectively. These amoebae cause significant morbidity and mortality rates. Thus, the identification, characterization and validation of molecules participating in host-parasite interactions can provide attractive targets to timely intervene disease progress. In this work, we present a compendium of the parasite adhesins, lectins, proteases, hydrolases, kinases, and others, that participate in key pathogenic events. Special focus is made for the analysis of assorted molecules and mechanisms involved in the interaction of the parasites with epithelial surface receptors, changes in epithelial junctional markers, implications on the barrier function, among others. This review allows the assessment of initial host-pathogen interaction, to correlate it to the potential of parasite invasion.
Topics: Acanthamoeba; Animals; Entamoeba histolytica; Epithelial Cells; Host-Parasite Interactions; Humans; Naegleria fowleri; Protozoan Infections
PubMed: 31416298
DOI: 10.3390/genes10080618 -
Scientific Reports Jan 2020Acanthamoeba spp. are predominant free-living amoebae of water and soil. They have been used as tools for the isolation and culture of microbes that resist after their...
Acanthamoeba spp. are predominant free-living amoebae of water and soil. They have been used as tools for the isolation and culture of microbes that resist after their phagocytosis, such as Legionella-like bacteria, and, more recently giant viruses for which differences in permissiveness have been reported. However, problems have been reported regarding their identification at the species level. The present work implemented specific PCR systems for the detection and identification of Acanthamoeba species through comparison of sequences and phylogenetic analyses. Thirty-three Acanthamoeba isolates were studied, including 20 reference strains and 13 isolates retrieved from water, soil or clinical samples. Previous delineation of a core genome encompassing 826 genes based on draft genome sequences from 14 Acanthamoeba species allowed designing PCR systems for one of these core genes that encodes an alanine-tRNA ligase. These primers allowed an efficient and specific screening to detect Acanthamoeba presence. In addition, they identified all 20 reference strains, while partial and complete sequences coding for 18S ribosomal RNA identified only 11 (55%). We found that four isolates may be considered as new Acanthamoeba species. Consistent with previous studies, we demonstrated that some Acanthamoeba isolates were incorrectly assigned to species using the 18S rDNA sequences. Our implemented tool may help determining which Acanthamoeba strains are the most efficient for the isolation of associated microorganisms.
Topics: Acanthamoeba; Acanthamoeba castellanii; Alanine-tRNA Ligase; Genes, Protozoan; Phylogeny; Polymerase Chain Reaction; RNA, Ribosomal, 18S
PubMed: 32005846
DOI: 10.1038/s41598-020-57998-5 -
Environmental Health and Preventive... Jun 2017Members of the genus Acanthamoeba are widely distributed throughout the world, and some of them are considered pathogenic, as they are capable of causing corneal and...
BACKGROUND
Members of the genus Acanthamoeba are widely distributed throughout the world, and some of them are considered pathogenic, as they are capable of causing corneal and central nervous system diseases. In this study, we isolated Acanthamoeba strains from soil and tap water in Yanji, China.
METHODS
We identified four strains of Acanthamoeba (CJY/S1, CJY/S2, CJY/S3, and CJY/W1) using mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) analysis. Nuclear 18S rDNA sequences were used for phylogenetic analysis and species identification.
RESULTS
Genotypic characterization of the isolates showed that they belonged to genotypes T4 (CJY/S1 and CJY/S2), T5 (CJY/S3), and T16 (CJY/W1). Sequence differences between CJY/S1 and Acanthamoeba castellanii Neff, CJY/S2 and Acanthamoeba KA/E7, and CJY/S3 and Acanthamoeba lenticulata 68-2 were 0.31, 0.2, and 0.26%, respectively. 18S ribosomal deoxyribonucleic acid (rDNA) of CJY/W1 had 99% sequence identity to that of Acanthamoeba sp. U/H-C1. Strains CJY/S1 and CJY/S2, isolated from soil, had similar mtDNA RFLP patterns, whereas strain CJY/W1, isolated from tap water, displayed a different pattern.
CONCLUSIONS
To the best of our knowledge, this is the first report on the identification of genotypes T4, T5, and T16 from environmental sources in Yanji, China.
Topics: Acanthamoeba; China; Databases, Nucleic Acid; Drinking Water; Electrophoresis; Genotype; Humans; Phylogeny; Polymorphism, Restriction Fragment Length; Sequence Analysis, RNA; Soil Microbiology; Water Microbiology
PubMed: 29165144
DOI: 10.1186/s12199-017-0655-2 -
PloS One 2021Free-living amoeba (FLA) is widely distributed in the natural environment. Since these amoebae are widely found in various waters, they pose an important public health...
Free-living amoeba (FLA) is widely distributed in the natural environment. Since these amoebae are widely found in various waters, they pose an important public health problem. The aim of this study was to detect the presence of Acanthamoeba, B. mandrillaris, and N. fowleri in various water resources by qPCR in Izmir, Turkey. A total of (n = 27) 18.24% Acanthamoeba and (n = 4) 2.7% N. fowleri positives were detected in six different water sources using qPCR with ITS regions (ITS1) specific primers. The resulting concentrations varied in various water samples for Acanthamoeba in the range of 3.2x105-1.4x102 plasmid copies/l and for N. fowleri in the range of 8x103-11x102 plasmid copies/l. The highest concentration of Acanthamoeba and N. fowleri was found in seawater and damp samples respectively. All 27 Acanthamoeba isolates were identified in genotype level based on the 18S rRNA gene as T4 (51.85%), T5 (22.22%), T2 (14.81%) and T15 (11.11%). The four positive N. fowleri isolate was confirmed by sequencing the ITS1, ITS2 and 5.8S rRNA regions using specific primers. Four N. fowleri isolates were genotyped (three isolate as type 2 and one isolate as type 5) and detected for the first time from water sources in Turkey. Acanthamoeba and N. fowleri genotypes found in many natural environments are straightly related to human populations to have pathogenic potentials that may pose a risk to human health. Public health professionals should raise awareness on this issue, and public awareness education should be provided by the assistance of civil authorities. To the best of our knowledge, this is the first study on the quantitative detection and distribution of Acanthamoeba and N. fowleri genotypes in various water sources in Turkey.
Topics: Acanthamoeba; DNA, Protozoan; Genotype; Linear Models; Naegleria fowleri; Phylogeny; Plasmids; RNA, Ribosomal, 5.8S; Reference Standards; Statistics, Nonparametric; Trophozoites; Turkey; Water
PubMed: 34437614
DOI: 10.1371/journal.pone.0256659 -
BMC Infectious Diseases Sep 2022Acanthamoeba is an emerging pathogen, infamous for its resilience against antiprotozoal compounds, disinfectants and harsh environments. It is known to cause keratitis,...
INTRODUCTION
Acanthamoeba is an emerging pathogen, infamous for its resilience against antiprotozoal compounds, disinfectants and harsh environments. It is known to cause keratitis, a sight-threatening, painful and difficult to treat corneal infection which is often reported among contact lens wearers and patients with ocular trauma. Acanthamoeba comprises over 24 species and currently 23 genotypes (T1-T23) have been identified.
AIMS
This retrospective study was designed to examine the Acanthamoeba species and genotypes recovered from patients with Acanthamoeba keratitis (AK), determine the presence of endosymbionts in ocular isolates of Acanthamoeba and review the clinical presentations.
METHODOLOGY
Thirteen culture-confirmed AK patients treated in a tertiary eye care facility in Hyderabad, India from February to October 2020 were included in this study. The clinical manifestations, medications and visual outcomes of all patients were obtained from medical records. The Acanthamoeba isolates were identified by sequencing the ribosomal nuclear subunit (rns) gene. Acanthamoeba isolates were assessed for the presence of bacterial or fungal endosymbionts using molecular assays, PCR and fluorescence in situ hybridization (FISH).
RESULTS
The mean age of the patients was 33 years (SD ± 17.4; 95% CI 22.5 to 43.5 years). Six (46.2%) cases had AK associated risk factors; four patients had ocular trauma and two were contact lens wearers. A. culbertsoni (6/13, 46.2%) was the most common species, followed by A. polyphaga and A. triangularis. Most of the isolates (12/13) belonged to genotype T4 and one was a T12; three sub-clusters T4A, T4B, and T4F were identified within the T4 genotype. There was no significant association between Acanthamoeba types and clinical outcomes. Eight (61.5%) isolates harboured intracellular bacteria and one contained Malassezia restricta. The presence of intracellular microbes was associated with a higher proportion of stromal infiltrates (88.9%, 8/9), epithelial defect (55.6%, 5/9) and hypopyon (55.6%, 5/9) compared to 50% (2/4), 25% (1/4) and 25% (1/4) AK cases without intracellular microbes, respectively.
CONCLUSIONS
Genotype T4 was the predominant isolate in southern India. This is the second report of T12 genotype identified from AK patient in India, which is rarely reported worldwide. The majority of the Acanthamoeba clinical isolates in this study harboured intracellular microbes, which may impact clinical characteristics of AK.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Disinfectants; Eye Infections; Genotype; Humans; In Situ Hybridization, Fluorescence; Retrospective Studies
PubMed: 36175838
DOI: 10.1186/s12879-022-07741-4