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Annals of Parasitology 2019Acanthamoeba spp. are free-living amoeba commonly found in environmental sources such as soil, water, and dust. This ubiquitous amoeba is the causative agent of amoebic...
Acanthamoeba spp. are free-living amoeba commonly found in environmental sources such as soil, water, and dust. This ubiquitous amoeba is the causative agent of amoebic keratitis (AK) and encephalitis. The present study aimed to investigate the presence of Acanthamoeba spp. in the water sources of Kermanshah city, Iran. Sixty water samples were taken from different localities of Kermanshah including agricultural canals, rivers, and swimming pools. Filtration and cultivation were carried out on non-nutrient agar medium (NNA). The axenic cultivation was performed for all of the positive isolates. PCR analysis was performed on positive samples. Sequencing was done for 12 PCR products. Genotypes were identified by blast search and homology analysis. The obtained data were analyzed using Statistical Package for the Social Sciences (SPSS 16) software. Acanthamoeba spp. was found in 46 (76.66%) water samples and amoebae were grown in the TYI-S-33 medium. Sequencing of 12 samples proved that Acanthamoeba belonged to T4 (75%), T2 (8.34%), T5 (8.33%) and T11 (8.33%) genotypes. In this study, Acanthamoeba T4 (75%), T2 (8.34%), T5 (8.33%) and T11 (8.33%) genotypes were isolated from the water of Kermanshah city. Thus, hygiene consideration is recommended to prevent the contamination.
Topics: Acanthamoeba; Fresh Water; Genotype; Iran
PubMed: 32191987
DOI: 10.17420/ap6504.226 -
Annals of Parasitology 2020The aim of this study was identification features of cultivation representatives of genus Acanthamoeba isolated from bentonite using Cellulosimicrobium sp. as a...
The aim of this study was identification features of cultivation representatives of genus Acanthamoeba isolated from bentonite using Cellulosimicrobium sp. as a bacteria-feeders. Identification of isolated bacteria was conducted by morphological, cultural and molecular-genetic methods. The cultivation of free-living „bentonite” amoeba on the lawn of Cellulosimicrobium sp. have gained significant advantages than using Escherichia coli as a bacteriafeeders was shown. “Bentonite” amoeba form crateroid plaques, which fit to the quantitative characteristic materials which contains amoeba, during deep co-cultivation Acanthamoeba sp. and Cellulosimicrobium sp. on 1% glucose meet-peptone agar.
Topics: Acanthamoeba; Actinobacteria; Culture Techniques; Parasitology
PubMed: 32198996
DOI: 10.17420/ap6601.238 -
Annals of Tropical Medicine and... Mar 1999
Topics: Acanthamoeba; Animals; Feces; Humans; Pakistan
PubMed: 10474646
DOI: 10.1080/00034989958690 -
Scientific Reports Nov 2021Acanthamoeba spp. are opportunistic human pathogens that cause granulomatous amoebic encephalitis and keratitis, and their accurate detection and enumeration in...
Acanthamoeba spp. are opportunistic human pathogens that cause granulomatous amoebic encephalitis and keratitis, and their accurate detection and enumeration in environmental samples is a challenge. In addition, information regarding the genotyping of Acanthamoeba spp. using various PCR methods is equally critical. Therefore, considering the diverse niches of habitats, it is necessary to develop an even more efficient genotyping method for Acanthamoeba spp. detection. This study improved the sensitivity of detection to avoid underestimation of Acanthamoeba spp. occurrence in aquatic environmental samples, and to accurately define the pathogenic risk by developing an efficient PCR method. In this study, a new nested genotyping method was established and compared with various PCR-based methods using in silico, lab, and empirical tests. The in silico test showed that many PCR-based methods could not successfully align specific genotypes of Acanthamoeba, except for the newly designed nested PCR and real-time PCR method. Furthermore, 52 water samples from rivers, reservoirs, and a river basin in Taiwan were analysed by six different PCR methods and compared for genotyping and detection efficiency of Acanthamoeba. The newly developed nested-PCR-based method of genotyping was found to be significantly sensitive as it could effectively detect the occurrence of Acanthamoeba spp., which was underestimated by the JDP-PCR method. Additionally, the present results are consistent with previous studies indicating that the high prevalence of Acanthamoeba in the aquatic environment of Taiwan is attributed to the commonly found T4 genotype. Ultimately, we report the development of a small volume procedure, which is a combination of recent genotyping PCR and conventional real-time PCR for enumeration of aquatic Acanthamoeba and acquirement of biologically meaningful genotyping information. We anticipate that the newly developed detection method will contribute to the precise estimation, evaluation, and reduction of the contamination risk of pathogenic Acanthamoeba spp., which is regularly found in the water resources utilised for domestic purposes.
Topics: Acanthamoeba; Environmental Monitoring; Genotyping Techniques; Polymerase Chain Reaction; Rivers
PubMed: 34741041
DOI: 10.1038/s41598-021-00968-2 -
Acta Tropica Aug 2005Acanthamoeba is an opportunistic protozoan that is widely distributed in the environment and can cause human infections. The life cycle of Acanthamoeba consists of an...
Acanthamoeba is an opportunistic protozoan that is widely distributed in the environment and can cause human infections. The life cycle of Acanthamoeba consists of an infective trophozoite form. However under harsh environmental conditions trophozoites differentiate into a double-walled, metabolically inactive and resistant cyst form. Research in Acanthamoeba has mostly focussed on the infective trophozoite form and its pathogenic mechanisms. In this study, we used Acanthamoeba isolates belonging to T1, T2, T3, T4, T7 genotypes and studied their cysts properties. We determined that food deprivation stimulates encystment in Acanthamoeba isolates belonging to T1, T2, T3, T4 and T7 genotypes in a sodium dodecyl sulfate (SDS)-resistant manner. In addition, increase in osmolarity triggered encystment in T1, T2, T3, T4 isolates (SDS-resistant) but T7 failed to encyst (SDS-labile). Adhesion assays revealed that Acanthamoeba cysts belonging to T1, T2, T3, T4, and T7 genotypes exhibited no and/or minimal binding (<5%) to the host cells. Fluorescein-labelled lectins showed that all Acanthamoeba isolates tested exhibited binding to concanavalin A, indicating the expression of mannosyl- and/or glucosyl-residues. Role of cysts in the transmission of infection is discussed further.
Topics: Acanthamoeba; Animals; Cell Adhesion; Cells, Cultured; Epithelium, Corneal; Genotype; Humans; Life Cycle Stages; Osmolar Concentration
PubMed: 15963936
DOI: 10.1016/j.actatropica.2005.05.004 -
Acta Parasitologica Dec 2018The genus Acanthamoeba is a free-living amoeba widely distributed in various aquatic environments. It is an etiologic cause of amoebic encephalitis and keratitis...
The genus Acanthamoeba is a free-living amoeba widely distributed in various aquatic environments. It is an etiologic cause of amoebic encephalitis and keratitis particularly for immunocompromised individuals. The purpose of the present study was to investigate Acanthamoeba species prevalence in household and hospital potable water in Beni-Suef governorate, Egypt, and to employ sequencing methods to identify positive Acanthamoeba species isolates and their potential health risks. Sixty tap water samples (30 household and 30 governmental and private hospital settings) collected from Beni-Suef governorate, Egypt were filtered, cultured on non-nutrient agar, identified by morphotyping keys after staining with Giemsa stain and then confirmed by PCR using Acanthamoeba specific primers. Twenty positive samples were successfully genetically characterized and phylogenetically analyzed to identify Acanthamoeba species. The total detection rate for Acanthamoeba was 48/60 (80%); Acanthamoeba contamination in water collected from domestic houses was higher than in hospitals; 27/30 (90%) versus 21/30 (70%) with statistical significant value (P value = 0.05). Sequencing of 20 positive isolates revealed Acanthamoeba T4 in 65% and T2 in 35%. To our knowledge, this is the first research that documents the occurrence and phylogeny of Acanthamoeba species in Beni-Suef, Egypt. The presence of a higher percentage of Acanthamoeba species in tap water, in particular T4, highlights the potential health hazards for immunocompromised individuals and emphasizes the urgent need for the implementation of effective filtration and disinfection measures.
Topics: Acanthamoeba; Cross-Sectional Studies; DNA, Protozoan; DNA, Ribosomal; Egypt; Hospitals, Private; Hospitals, Public; Housing; Likelihood Functions; Phylogeny; Polymerase Chain Reaction; Water; Water Supply
PubMed: 30367777
DOI: 10.1515/ap-2018-0101 -
Current Microbiology Sep 2001Acanthamoeba are opportunistic pathogens with invasive and noninvasive species. For clinical purposes it is important to differentiate potentially pathogenic from...
Acanthamoeba are opportunistic pathogens with invasive and noninvasive species. For clinical purposes it is important to differentiate potentially pathogenic from nonpathogenic isolates. For the rapid and sensitive identification of Acanthamoeba at the genus level, we used a polymerase chain reaction (PCR)-based method which detected as few as five cells. Further, we tested nine isolates of Acanthamoeba for their ability to produce cytopathic effects (CPE) on corneal epithelial cells. On the basis of the results, Acanthamoeba were divided into pathogenic or nonpathogenic groups. However, because CPE assays are not available to every diagnostic laboratory, we developed a simple plating assay based on osmotolerance which correlated well with the CPE assays. Pathogenic Acanthamoeba showed growth on higher osmolarity (agar plates containing one molar mannitol), while growth of nonpathogens was inhibited on these plates. In conclusion, we have developed methods for the rapid identification and differentiation of Acanthamoeba.
Topics: Acanthamoeba; Animals; Cells, Cultured; Culture Media; DNA, Protozoan; Epithelium, Corneal; Mannitol; Osmolar Concentration; Polymerase Chain Reaction; Rabbits; Sensitivity and Specificity
PubMed: 11400071
DOI: 10.1007/s002840010288 -
Scientific Reports Aug 2021A survey of Acanthamoeba in 100 public freshwater sources in 28 provinces across Thailand has identified 9 genotypes comprising T2/6, T3-T5, T9, T11, T12, T18 and a...
A survey of Acanthamoeba in 100 public freshwater sources in 28 provinces across Thailand has identified 9 genotypes comprising T2/6, T3-T5, T9, T11, T12, T18 and a novel 'T23' among 131 isolates. Sequencing of the near complete 18S rRNA gene of Acanthamoeba of all isolates has shown that the most predominant genotype T4 found in 87 isolates (66.4%) contained 4 subtypes, i.e. T4A, T4B, T4C and T4F, while all isolates assigned to genotype T2/6 belonged to subtype B. Among intron-bearing genotypes, most isolates harbouring genotype T3 contained S516 introns, characterised by 3 distinct variants whilst all genotypes T4A and T5 were intronless. Identical 18S rRNA sequences of Acanthamoeba were identified across regions of the country and four isolates in this study shared the same sequences with those from remote nations, suggesting that some strains have reproductive success in diverse ecological niche. Nucleotide diversity of genotypes T2/6B, T3, T4, T9 and T11 in this study was significantly less than that among global isolates outside Thailand, implying that limited sequence diversity occurred within local populations. A remarkably higher level of nucleotide diversity in genotype T11 than those of other genotypes (0.041 vs. 0.012-0.024) could be due to cryptic subtypes. Recombination breakpoints have been detected within genotypes and subtypes as well as within isolates despite no evidence for sexual and parasexual cycles in the genus Acanthamoeba. Tajima's D, Fu & Li's D* and F* statistics revealed significantly negative deviation from neutrality across genotypes and subtypes, implying purifying selection in this locus. The 18S rRNA gene of the novel genotype 'T23' displayed 7.82% to 28.44% sequence differences in comparison with all known genotypes. Both Bayesian and maximum likelihood phylogenetic trees have placed genotype T23 as sister to the clade comprising genotypes T10, T12 and T14, all of these possess cyst structure belonging to morphological group III. Hence, Acanthamoeba bangkokensis sp. nov. is proposed for this novel genotype. It is likely that more genotypes of Acanthamoeba remain to be discovered while the evolution of the 18S rRNA gene of this pathogenic-free living amoeba seems to be ongoing.
Topics: Acanthamoeba; Bayes Theorem; Fresh Water; Genotype; Introns; Phylogeny; RNA, Ribosomal, 18S; Sequence Analysis, DNA; Thailand
PubMed: 34453084
DOI: 10.1038/s41598-021-96690-0 -
Parasitology Research Sep 2016T4 is the Acanthamoeba genotype most related to cases of granulomatous amoebic encephalitis (GAE) in immunocompromised patients and of keratitis in contact lens wearers....
T4 is the Acanthamoeba genotype most related to cases of granulomatous amoebic encephalitis (GAE) in immunocompromised patients and of keratitis in contact lens wearers. The determination of the pathogenic potential of Acanthamoeba clinical and environmental isolates using experimental models is extremely important to elucidate the capacity of free-living organisms to establish and cause disease in hosts. The aim of this study was to compare and evaluate the histopathology and culture between two different routes of experimental infection of T4 Acanthamoeba isolated from environmental and clinical source in mice (intracranial and intraperitoneal). Swiss isogenic healthy mice were inoculated with 10(4) trophozoites by intracranial (IC) and intraperitoneal (IP) routes and observed during 21 days. The brains from animals inoculated by the IC route were collected and from the animals of the IP inoculation group, the brains, livers, kidneys, spleens, and lungs were removed. The organs were prepared and appropriately divided to be evaluated with histopathology and culture. There was no significant difference between the inoculation routes in terms of isolates recovery (χ(2) = 0.09; p = 0.76). In the IC group, isolate recovery rate was significantly higher in histopathology than the one achieved by culture (χ(2) = 6.45; p < 0.01). Experimental infection revealed that all isolates inoculated could be considered invasive because it was possible to recover evolutive forms of Acanthamoeba in both routes. This work represents the first in vivo pathogenicity assay of primary isolation source in Central region of Brazil showing in vivo pathogenicity and hematogenous spread capacity of these protozoa, improving the knowledge on free-living amoebae isolates.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Amebiasis; Animals; Brain; Brazil; Female; Genotype; Humans; Keratitis; Male; Mice; Trophozoites; Virulence
PubMed: 27164833
DOI: 10.1007/s00436-016-5105-3 -
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