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PloS One 2021Acanthamoeba spp. are one of the free-living amoeba that spread worldwide causing keratitis. Owing to the increase in the use of lenses, whether for medical or cosmetic...
BACKGROUND
Acanthamoeba spp. are one of the free-living amoeba that spread worldwide causing keratitis. Owing to the increase in the use of lenses, whether for medical or cosmetic purposes, the incidence of disease increases every year. Contamination of the lenses with the Acanthamoeba trophozoites or cysts may lead to eye infection and cause sight-threatening keratitis in human. We isolated Acanthamoeba spp. from new lenses, used lenses, and contact lens disinfecting solutions and identified them based on morphological characteristics and molecular test.
METHODS
New and used lenses and contact lens disinfecting solutions were cultured on monogenic media. Light and scanning electron microscope was used to identify Acanthamoeba spp. morphological features. Genotype identification was also evaluated using PCR sequencing of 18S rRNA gene specific primer pair JDP1 and JDP2.
RESULTS
A hundred samples were examined, 29 (29%) were infected with Acanthamoeba spp. That belonged to two strains of Acanthamoeba (Acanthamoeba 41 and Acanthamoeba 68). 18S rRNA of the Acanthamoeba 41 had 99.69% sequence identity to Acanthamoeba castellanii clone HDU-JUMS-2, whereas Acanthamoeba 68 had 99.74% similar pattern to that of Acanthamoeba sp. isolate T4 clone ac2t4 that are morphologically identified as Acanthamoeba polyphaga. The obtained data revealed that the isolated strains belong to T4 genotype that was evolutionarily similar to strains isolated in Iran.
CONCLUSIONS
Cosmetic lenses and disinfectant solutions are a major transmissible mode for infection. This genotype is common as the cause of Acanthamoeba keratitis. To avoid infection, care must be taken to clean the lenses and their preservative solutions and prevent contamination with the parasite.
Topics: Acanthamoeba; Contact Lens Solutions; Contact Lenses; Cosmetics; DNA, Ribosomal; Drug Contamination; Egypt; Humans; Iran; Microscopy; Microscopy, Electron, Scanning; Phylogeny; Polymerase Chain Reaction; RNA, Ribosomal, 18S; Sequence Analysis, DNA
PubMed: 34780533
DOI: 10.1371/journal.pone.0259847 -
Clinical & Experimental Optometry Nov 2020This study examined the prevalence of free-living Acanthamoeba in domestic tap water in the greater Sydney region, Australia, and determined any seasonal variation in...
BACKGROUND
This study examined the prevalence of free-living Acanthamoeba in domestic tap water in the greater Sydney region, Australia, and determined any seasonal variation in prevalence.
METHODS
Fifty-four participants were included in this study following approval from an institutional human research ethics committee. Each participant self-collected two samples (one in summer and another in winter) from the surface of the drain of the bathroom sink using an instructional kit. The samples were cultured by inoculating onto a non-nutrient agar plate seeded with Escherichia coli and incubation at 32°C for two weeks. The plates were microscopically examined for the presence of free-living amoeba. DNA was isolated from 20 samples and a polymerase chain reaction (PCR) assay was performed for amplification of the partial sequence of the 18S ribosomal RNA gene. The PCR amplified products were sequenced using Sanger sequencing and genotyping was performed based on the variation in nucleotide sequences.
RESULTS
A total of 97 samples were collected over the two collection periods, with 28.6 per cent of samples morphologically classified as Acanthamoeba. The summer period yielded 16 of 54 (29.6 per cent) samples classified as Acanthamoeba, while the winter period yielded 12 of 43 (27.9 per cent) samples classified as Acanthamoeba. There was no statistically significant difference (p = 0.85) between the prevalence of free-living Acanthamoeba in summer compared to winter. Phylogenetic analysis showed that 15 of 20 (75 per cent) isolates belonged to genotype T4, the most frequent genotype isolated in Acanthamoeba keratitis.
CONCLUSION
The prevalence of free-living Acanthamoeba characterised morphologically in domestic tap water of the greater Sydney region was higher than expected, especially considering the low incidence of Acanthamoeba keratitis in Australia. However, this study did not find variation between seasons. As the T4 genotype was most common, Sydney-based practitioners must always consider Acanthamoeba as a possible causative organism in cases of microbial keratitis, regardless of the season.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Humans; Phylogeny; Prevalence; Seasons; Water
PubMed: 32227362
DOI: 10.1111/cxo.13065 -
Parasite (Paris, France) Jun 2008The free-living amoebae (FLA) are ubiquitous and opportunistic protozoa. They can induce human and animal diseases. The aim of our study was to detect the FLA and...
UNLABELLED
The free-living amoebae (FLA) are ubiquitous and opportunistic protozoa. They can induce human and animal diseases. The aim of our study was to detect the FLA and Acanthamoeba genus in the hydraulic system of an hemodialysis unit. It was a prospective study of 46 water samples. The first collect (23) was before cleaning and after the haemodialysis sessions and the second (23) after cleaning and before the hemodialysis sessions.
RESULTS
the morphological study enabled us to detect morphotypic diversity. The predominant morphotypes were the acanthopodial forms (29%). At the entrance of hemodialysis unit there were acanthopodial (44%) and monotactic (25%) forms; at the outlet, acanthopodial and fan-shaped forms (25% each). In addition, Acanthamoeba genus was present in 39% (1st collect) and 18% (2nd collect). The amplification of the FLA 18S rDNA gene was negative in only one sample localized in the last stage of water treatment unit (WTU). The amplification of the 18S rDNA (ASA.A1) Acanthamoeba gene was positive in 15 samples.
CONCLUSIONS
we noted that, in the hemodialysis unit, the purification techniques used in the WTU were effective, but there is a problem of water stagnation in the drain, which constitutes an appropriate condition for the biofilms formation. It is then necessary to use a filter with a low porosity (0.2 microm) at the entrance of the hemodialysis unit and if possible to change the drain.
Topics: Acanthamoeba; Animals; DNA, Protozoan; DNA, Ribosomal; Equipment Contamination; Gene Amplification; Humans; Kidneys, Artificial; Phylogeny; Prevalence; Sequence Analysis, DNA; Tunisia
PubMed: 18642506
DOI: 10.1051/parasite/2008152137 -
The Korean Journal of Parasitology Aug 2022The high percentage of Vermamoeba was found in tap water in Korea. This study investigated whether Vermamoeba induced allergic airway inflammation in mice. We selected 2...
The high percentage of Vermamoeba was found in tap water in Korea. This study investigated whether Vermamoeba induced allergic airway inflammation in mice. We selected 2 free-living amoebas (FLAs) isolated from tap water, which included Korean FLA 5 (KFA5; Vermamoeba vermiformis) and 21 (an homolog of Acanthamoeba lugdunensis KA/ E2). We axenically cultured KFA5 and KFA21. We applied approximately 1 × 106 to mice's nasal passages 6 times and investigated their pathogenicity. The airway resistance value was significantly increased after KFA5 and KFA21 treatments. The eosinophil recruitment and goblet cell hyperplasia were concomitantly observed in bronchial alveolar lavage (BAL) fluid and lung tissue in mice infected with KFA5 and KFA21. These infections also activated the Th2-related interleukin 25, thymic stromal lymphopoietin, and thymus and activation-regulated chemokines gene expression in mouse lung epithelial cells. The CD4+ interleukin 4+ cell population was increased in the lung, and the secretion of Th2-, Th17-, and Th1-associated cytokines were upregulated during KFA5 and KFA21 infection in the spleen, lung-draining lymph nodes, and BAL fluid. The pathogenicity (allergenicity) of KFA5 and KFA21 might not have drastically changed during the long-term in vitro culture. Our results suggested that Vermamoeba could elicit allergic airway inflammation and may be an airway allergen.
Topics: Acanthamoeba; Amoeba; Animals; Bronchoalveolar Lavage Fluid; Eosinophils; Inflammation; Mice; Water
PubMed: 36041484
DOI: 10.3347/kjp.2022.60.4.229 -
The Ocular Surface Apr 2010Acanthamoeba keratitis (AK) is a serious infection of the cornea. At present, diagnosis of the disease is not straightforward and treatment is very demanding. While... (Review)
Review
Acanthamoeba keratitis (AK) is a serious infection of the cornea. At present, diagnosis of the disease is not straightforward and treatment is very demanding. While contact lens wear is the leading risk factor for A K, Acanthamoeba parasites are increasingly recognized as an important cause of keratitis in non-contact lens wearers. The first critical step in the pathogenesis of infection is the adhesion of the microbe to the surface of the host tissues. Acanthamoebae express a major virulence protein, the mannose-binding protein (MBP), which mediates the adhesion of amoebae to the surface of the cornea. The MBP is a transmembrane protein with characteristics of a typical cell surface receptor. Subsequent to the MBP-mediated adhesion to host cells, the amoebae produce a contact-dependent metalloproteinase and several contact-independent serine proteinases. These proteinases work in concert to produce a potent cytopathic effect (CPE ) involving killing of the host cells, degradation of epithelial basement membrane and underlying stromal matrix, and penetration into the deeper layers of the cornea. In the hamster animal model, oral immunization with the recombinant MBP protects against AK, and this protection is associated with an increased level of anti-MBP IgA in tears of protected animals. Normal human tear fluid contains IgA antibodies against Acanthamoeba MBP that is likely to provide protection by inhibiting the adhesion of parasites to host cells. Indeed, in in vitro CPE assays, even a low concentration of tears (10 microL of undiluted tears per milliliter of media) almost completely inhibits Acanthamoeba-induced CPE . In addition to adherence-inhibiting, IgA-mediated protection, human tears also contain IgA-independent factors that provide protection against Acanthamoeba-induced CPE by inhibiting the activity of cytotoxic proteinases. Characterization of the CPE-inhibitory factors of human tears should lead to a better understanding of the mechanism by which the tissues of the host resist the infection and also help decode circumstances that predispose to Acanthamoeba infections.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Animals; Cell Adhesion; Cornea; Humans; Mannose-Binding Lectin; Protozoan Proteins
PubMed: 20427010
DOI: 10.1016/s1542-0124(12)70071-x -
Microbes and Infection Apr 2006Acanthamoeba spp. are free-living amoebae that cause Acanthamoeba keratitis, a blinding corneal infection. The innate immune apparatus is crucial for the resolution of... (Review)
Review
Acanthamoeba spp. are free-living amoebae that cause Acanthamoeba keratitis, a blinding corneal infection. The innate immune apparatus is crucial for the resolution of the disease. With the exception of mucosal antibody, elements of the adaptive immune system fail to prevent infection or contribute to its resolution in experimental animals.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Animals; Cricetinae; Disease Models, Animal; Humans
PubMed: 16697233
DOI: 10.1016/j.micinf.2005.12.009 -
Parasite (Paris, France) Mar 2010The aim of our study was to detect free-living Amoebae (FLA) by morphological methods and to identify Acanthamoeba spp. by PCR in the dental unit water lines (DUWL).
UNLABELLED
The aim of our study was to detect free-living Amoebae (FLA) by morphological methods and to identify Acanthamoeba spp. by PCR in the dental unit water lines (DUWL).
MATERIALS AND METHODS
it was a prospective study dealing with 196 water samples collected from DUWL (94 samples taken in the early morning before materials flush and patient consultations and 102 samples taken after consultations). At the same time, 39 samples from tap water were realized.
RESULTS
135 (69%) samples were positives by the morphological study with morpholypical diversity. The predominant morphotype was the monopodial (39.2%). 18 strains of Acanthamoeba spp. were detected in DUW (13.%) and three strains in tap water (10%). The amplification of 18S rDNA gene of these strains of Acanthamoeba spp. was positive for all samples.
CONCLUSION
the FLA and Acanthamoeba were isolated both in tap water and in dental unit. The amoeba pathogenicity has not been demonstrated after oral or dental contamination; but the presence of intracellular and pathogenic bacteria in the amoeba could be a source of microbiological risks for patients in case of deep dental care or immunodepression. The improvement of this dental unit was necessary by putting a filter of 0.2 microns porosity before the arrival of the water in hand-pieces allowing the limitation of FLA passage.
Topics: Acanthamoeba; Animals; DNA, Protozoan; DNA, Ribosomal; Dental Equipment; Fresh Water; Humans; Polymerase Chain Reaction; Prospective Studies; Schools, Medical; Tunisia; Universities
PubMed: 20387741
DOI: 10.1051/parasite/2010171067 -
Scientific Reports Jul 2020Acanthamoeba can cause visually destructive Acanthamoeba keratitis (AK) in contact lens (CL) users. The purpose of this study was to determine whether Acanthamoeba was...
Acanthamoeba can cause visually destructive Acanthamoeba keratitis (AK) in contact lens (CL) users. The purpose of this study was to determine whether Acanthamoeba was present in the CL cases of CL wearers and to develop techniques to prevent the contaminations. To accomplish this, 512 CL case samples were collected from 305 healthy CL wearers. Using real-time PCR, Acanthamoeba DNA was detected in 19.1% of CL cases, however their presence was not directly associated with poor CL case care. Instead, the presence of Acanthamoeba DNA was associated with significant levels of many different bacterial species. When the CL cases underwent metagenomic analysis, the most abundant bacterial orders were Enterobacteriales followed by Burkholderiales, Pseudomonadales, and Flavobacteriales. The presence of Acanthamoeba was characterized by Propionibacterium acnes and Rothia aeria and was also associated with an increase in the α diversity. Collectively, Acanthamoeba contamination occurs when a diversified bacterial flora is present in CL cases. This can effectively be prevented by careful and thorough CL case care.
Topics: Acanthamoeba; Adult; Contact Lenses; DNA, Bacterial; Female; Humans; Hygiene; Male; Middle Aged; Polymerase Chain Reaction; Risk Factors
PubMed: 32724150
DOI: 10.1038/s41598-020-69554-2 -
International Journal of Antimicrobial... Nov 2021Acanthamoebae are opportunistic pathogens that cause serious infections, including Acanthamoeba keratitis, a sight-threatening disease affecting mainly contact lens...
Acanthamoebae are opportunistic pathogens that cause serious infections, including Acanthamoeba keratitis, a sight-threatening disease affecting mainly contact lens wearers, and granulomatous amoebic encephalitis, an infection of the central nervous system that occurs mostly in immunocompromised individuals. Although these infections are rare, they are a challenge for healthcare providers. In the last decade, the search for and implementation of novel treatment approaches against these parasites and the infections they cause have intensified, but current options are still unsatisfactory. The aim of this study was to investigate the in vitro activity of the gold-based compound auranofin against Acanthamoeba spp. The study showed that auranofin has potent antimicrobial activity against Acanthamoeba spp., with an IC ranging from 2.9 to 3.48 µM, and thus may be useful in the prevention and control of Acanthamoeba infections.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Amebiasis; Antiparasitic Agents; Auranofin; Encephalitis; Humans; Parasitic Sensitivity Tests
PubMed: 34419578
DOI: 10.1016/j.ijantimicag.2021.106425 -
PloS One 2021Accurate and rapid diagnosis of Acanthamoeba keratitis (AK) is difficult. Although the diagnostic procedure for AK has improved, further development and effective...
Accurate and rapid diagnosis of Acanthamoeba keratitis (AK) is difficult. Although the diagnostic procedure for AK has improved, further development and effective diagnostic tool utilization for AK need to continue. Chorismate mutase is a key regulatory enzyme involved in the shikimate pathway, a metabolic pathway absent in mammals but central for amino acid biosynthesis in bacteria, fungi, algae, and plants. In this study, we describe the identification and production of a polyclonal peptide antibody targeting chorismate mutase secreted by A. castellanii, which could be used for AK diagnosis. Western blot was performed using the protein lysates and conditioned media of the human corneal epithelial (HCE) cells, non-pathogenic Acanthamoeba, pathogenic Acanthamoeba, clinical isolate of Acanthamoeba spp., and other causes of keratitis such as Fusarium solani, Pseudomonas aeruginosa, and Staphylococcus aureus. Polyclonal antibodies raised against A. castellanii chorismate mutase specifically interacted with lysates of Acanthamoeba origin and their culture media, while such interactions were not observed from other samples. Acanthamoeba-specificity of chorismate mutase was also confirmed using immunocytochemistry after co-culturing Acanthamoeba with HCE cells. Specific binding of the chorismate mutase antibody to Acanthamoeba was observed, which were absent in the case of HCE cells. These results indicate that the chorismate mutase antibody of Acanthamoeba may serve as a method for rapid and differential Acanthamoeba identification.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Antibodies; Cell Line; Chorismate Mutase; Epithelial Cells; Humans; Peptides
PubMed: 33891646
DOI: 10.1371/journal.pone.0250342