scholarly journals Molecular Identification of Pathogenic Free-Living Amoeba from Household Biofilm Samples in Iran: A Risk Factor for Acanthamoeba Keratitis

2021 ◽  
Vol 9 (10) ◽  
pp. 2098
Author(s):  
Maryam Norouzi ◽  
Reza Saberi ◽  
Maryam Niyyati ◽  
Jacob Lorenzo-Morales ◽  
Hamed Mirjalali ◽  
...  
Keyword(s):  
Contact Lenses ◽  
Opportunistic Infections ◽  
Acanthamoeba Keratitis ◽  
Free Living ◽  
Pathogenic Potential ◽  
Ability Test ◽  
Soft Contact Lenses ◽  
Increased Risk ◽  
Free Living Amoeba ◽  
Causative Agents

Free-living amoeba (FLA) are ubiquitously distributed in the environment. However, they are also the causative agents of opportunistic infections in humans and other animals. A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. Moreover, FLA have been detected in various biofilms around the world. Therefore, the present study aimed to check for presence of FLA in samples from household biofilms in Iran and to characterize them at the molecular level. A total of 69 biofilm samples collected from showerheads, kitchen areas, and bathroom sinks were analyzed. Positive samples for FLA were characterized at the morphological and molecular levels. Furthermore, the results of morphology analysis indicated that 26.08% (18/69) of biofilm samples were positive for Acanthamoeba spp., Vermamoeba genus, and Vahlkampfiids. According to sequence analysis, five strains of Acanthamoeba isolates related to the T4 genotype and two strains belonged to the T2 genotype. In addition, the pathogenic potential of Acanthamoeba-positive isolates was conducted using the tolerance ability test. The results of BLASTn of Vermamoeba sequences were similar to what was expected for Vermamoeba vermiformis. The above-mentioned reasons revealed that the relative high contamination of household biofilm samples with FLA may pose a risk for people using soft contact lenses and for patients with traumatic cataract. Our finding proposes that filtration should be performed in shower heads and indicates the need to monitor people at increased risk of Acanthamoeba keratitis.

scholarly journals Encystment Induces Down-Regulation of an Acetyltransferase-Like Gene in Acanthamoeba castellanii

Pathogens ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 321 ◽  
Author(s):  
Steven Rolland ◽  
Luce Mengue ◽  
Cyril Noël ◽  
Stéphanie Crapart ◽  
Anne Mercier ◽  
...  
Keyword(s):  
Bioinformatics Analysis ◽  
Acanthamoeba Castellanii ◽  
Acanthamoeba Keratitis ◽  
Free Living ◽  
Adverse Conditions ◽  
Genetic Modifications ◽  
Granulomatous Amoebic Encephalitis ◽  
Free Living Amoeba ◽  
Causative Agents

Acanthamoeba castellanii is a ubiquitous free-living amoeba. Pathogenic strains are causative agents of Acanthamoeba keratitis and granulomatous amoebic encephalitis. In response to adverse conditions, A. castellanii differentiate into cysts, which are metabolically inactive and resistant cells. This process, also named encystment, involves biochemical and genetic modifications that remain largely unknown. This study characterizes the role of the ACA1_384820 Acanthamoeba gene during encystment. This gene encodes a putative N-acetyltransferase, belonging to the Gcn5-related N-acetyltransferase (GNAT) family. We showed that expression of the ACA1_384820 gene was down-regulated as early as two hours after induction of encystment in A. castellanii. Interestingly, overexpression of the ACA1_384820 gene affects formation of cysts. Unexpectedly, the search of homologs of ACA1_384820 in the Eukaryota gene datasets failed, except for some species in the Acanthamoeba genus. Bioinformatics analysis suggested a possible lateral acquisition of this gene from prokaryotic cells. This study enabled us to describe a new Acanthamoeba gene that is down-regulated during encystment.

scholarly journals Isoniazid Conjugated Magnetic Nanoparticles Loaded with Amphotericin B as a Potent Antiamoebic Agent against Acanthamoeba castellanii

Antibiotics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 276
Author(s):  
Kawish Iqbal ◽  
Sumayah Abdelnasir Osman Abdalla ◽  
Ayaz Anwar ◽  
Kanwal Muhammad Iqbal ◽  
Muhammad Raza Shah ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Amphotericin B ◽  
Central Nervous System Infection ◽  
Acanthamoeba Castellanii ◽  
Acanthamoeba Keratitis ◽  
Free Living ◽  
Granulomatous Amoebic Encephalitis ◽  
Nano Drug Delivery ◽  
Free Living Amoeba ◽  
Acanthamoeba Species

The pathogenic free-living amoeba, Acanthamoeba castellanii, is responsible for a rare but deadly central nervous system infection, granulomatous amoebic encephalitis and a blinding eye disease called Acanthamoeba keratitis. Currently, a combination of biguanides, amidine, azoles and antibiotics are used to manage these infections; however, the host cell cytotoxicity of these drugs remains a challenge. Furthermore, Acanthamoeba species are capable of transforming to the cyst form to resist chemotherapy. Herein, we have developed a nano drug delivery system based on iron oxide nanoparticles conjugated with isoniazid, which were further loaded with amphotericin B (ISO-NPs-AMP) to cause potent antiamoebic effects against Acanthamoeba castellanii. The IC50 of isoniazid conjugated with magnetic nanoparticles and loaded with amphotericin B was found to be 45 μg/mL against Acanthamoeba castellanii trophozoites and 50 μg/mL against cysts. The results obtained in this study have promising implications in drug discovery as these nanomaterials exhibited high trophicidal and cysticidal effects, as well as limited cytotoxicity against rat and human cells.

scholarly journals Enhanced Killing of Acanthamoeba Cysts with a Plant Peroxidase-Hydrogen Peroxide-Halide Antimicrobial System

2003 ◽  
Vol 69 (5) ◽  
pp. 2563-2567 ◽  
Author(s):  
Reanne Hughes ◽  
Peter W. Andrew ◽  
Simon Kilvington
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
Contact Lens ◽  
Acanthamoeba Keratitis ◽  
Free Living ◽  
Soybean Peroxidase ◽  
Plant Peroxidase ◽  
Time Points ◽  
Free Living Amoeba ◽  
Care Systems

ABSTRACT The activity of H2O2 against the resistant cyst stage of the pathogenic free-living amoeba Acanthamoeba was enhanced by the addition of KI and either horseradish peroxidase or soybean peroxidase or, to a lesser degree, lactoperoxidase. This resulted in an increase in the cysticidal activity of 3% (wt/vol) H2O2, and there was >3-log killing in 2 h, compared with the 6 h required for comparable results with the peroxide solution alone (P < 0.05). With 2% H2O2, enhancement was observed at all time points (P < 0.05), and total killing of the cyst inoculum occurred at 4 h, compared with 6 h for the peroxide alone. The activity of sublethal 1% H2O2 was enhanced to give 3-log killing after 8 h of exposure (P < 0.05). No enhancement was obtained when KCl or catalase was used as a substitute in the reaction mixtures. The H2O2 was not neutralized in the enhanced system during the experiments. However, in the presence of a platinum disk used to neutralize H2O2 in contact lens care systems, the enhanced 2% H2O2 system gave 2.8-log killing after 6 h or total cyst killing by 8 h, and total neutralization of the H2O2 occurred by 4 h. In contrast, 2% H2O2 alone resulted in <0.8-log killing of cysts in the presence of the platinum disk due to rapid (<1 h) neutralization of the peroxide. Our observations could result in significant improvement in the efficacy of H2O2 contact lens disinfection systems against Acanthamoeba cysts and prevention of acanthamoeba keratitis.

Swimming with soft contact lenses: danger of acanthamoeba keratitis

2005 ◽  
Vol 5 (6) ◽  
pp. 392 ◽  
Author(s):  
Yuichi Kaji ◽  
Beihua Hu ◽  
Keisuke Kawana ◽  
Tetsuro Oshika
Keyword(s):  
Contact Lenses ◽  
Acanthamoeba Keratitis ◽  
Soft Contact ◽  
Soft Contact Lenses

scholarly journals Acanthamoeba keratitis related to contact lens in a tertiary hospital in China

2019 ◽  
Author(s):  
Weiwei Li ◽  
Zhiqun Wang ◽  
Jinghao Qu ◽  
Yang Zhang ◽  
Xuguang Sun
Keyword(s):  
Confocal Microscopy ◽  
Contact Lens ◽  
Contact Lenses ◽  
Early Stage ◽  
Tap Water ◽  
Acanthamoeba Keratitis ◽  
Tertiary Hospital ◽  
Chi Square ◽  
Soft Contact Lenses ◽  
Chi Square Test

Abstract Backgroud To report the clinical and microbiological features of Acanthamoeba keratitis (AK) related to contact lens in a tertiary hospital in China. Methods In this retrospective study, medical results of 61 cases of AK related to contact lens were reviewed from January 2000 to December 2017. The data included patients’ demographics, lens type, history, risk factors, the disease stages, reports of corneal scrapings and culture, treatment. Moreover, the genotype identification of part of these isolates was carried out with a PCR assay and sequence analysis of the 18S ribosomal DNA gene. Results There were 64 eyes included in the study. And 32.8% of cases wore soft contact lenses, 67.2% of patients used overnight orthokeratology. In the cases (20eyes) of early stage, 65% (13 eyes) had positive results in Giemsa stained smears, trophozoites were seen in 7 eyes (35%) in 0.9% sodium chloride (NaCl) wet mounts. Six eyes (30%) were diagnosed by confocal microscopy together with clinical sign. In the orthokeratology patients, 87.8% (36/41) of cases rinsed the lenses and/or cases with tap water, while 55% of soft lens wearers wore their lens during showering. The genotype of 9 isolates was determined, all the strains belonged to genotype T4. In the orthokeratology related cases, patients required therapeutic penetrating keratoplasty after 2005 were less than before 2005 (Chi-square test, χ2= 4.209，P = 0.04). Conclusions More than two thirds of cases were associated with orthokeratology. The examinations of Giemsa stained smears, 0.9% NaCl wet mounts and confocal microscopy should be done for the highly suspected cases of early stage to help the early diagnosis. The rate of therapeutic keratoplasty was decrease after 2005 compare with before 2005 in the cases of orthokeratology.

scholarly journals The potential pathogenicity of chlorhexidine-sensitive Acanthamoeba strains isolated from contact lens cases from asymptomatic individuals in Tenerife, Canary Islands, Spain

2008 ◽  
Vol 57 (11) ◽  
pp. 1399-1404 ◽  
Author(s):  
Carmen M. Martín-Navarro ◽  
Jacob Lorenzo-Morales ◽  
M. Gabriela Cabrera-Serra ◽  
Fernando Rancel ◽  
Nieves M. Coronado-Álvarez ◽  
...  
Keyword(s):  
Canary Islands ◽  
Contact Lens ◽  
Contact Lenses ◽  
Pathogenic Potential ◽  
Biochemical Assays ◽  
Rdna Sequencing ◽  
Causative Agents ◽  
Asymptomatic Individuals ◽  
Potential Pathogenicity ◽  
High Pathogenic

Pathogenic strains of the genus Acanthamoeba are causative agents of a serious sight-threatening infection of the eye known as Acanthamoeba keratitis. The prevalence of this infection has risen in the past 20 years, mainly due to the increase in number of contact lens wearers. In this study, the prevalence of Acanthamoeba in a risk group constituted by asymptomatic contact lens wearers from Tenerife, Canary Islands, Spain, was evaluated. Contact lenses and contact lens cases were analysed for the presence of Acanthamoeba isolates. The isolates' genotypes were also determined after rDNA sequencing. The pathogenic potential of the isolated strains was subsequently established using previously described molecular and biochemical assays, which allowed the selection of three strains with high pathogenic potential. Furthermore, the sensitivity of these isolates against two standard drugs, ciprofloxacin and chlorhexidine, was analysed. As the three selected strains were sensitive to chlorhexidine, its activity and IC50 were evaluated. Chlorhexidine was found to be active against these strains and the obtained IC50 values were compared to the concentrations of this drug present in contact lens maintenance solutions. It was observed that the measured IC50 was higher than the concentration found in these maintenance solutions. Therefore, the ineffectiveness of chlorhexidine-containing contact lens maintenance solutions against potentially pathogenic strains of Acanthamoeba is demonstrated in this study.

scholarly journals A Rabbit Model of Acanthamoeba Keratitis: Use of Infected Soft Contact Lenses After Corneal Epithelium Debridement With a Diamond Burr

2017 ◽  
Vol 58 (2) ◽  
pp. 1218 ◽  
Author(s):  
Ángel Ortillés ◽  
Pilar Goñi ◽  
Encarnación Rubio ◽  
Marta Sierra ◽  
Ekaterina Gámez ◽  
...  
Keyword(s):  
Corneal Epithelium ◽  
Contact Lenses ◽  
Rabbit Model ◽  
Acanthamoeba Keratitis ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Diamond Burr

scholarly journals Acanthamoeba keratitis related to contact lens use in a tertiary hospital in China

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Weiwei Li ◽  
Zhiqun Wang ◽  
Jinghao Qu ◽  
Yang Zhang ◽  
Xuguang Sun
Keyword(s):  
Confocal Microscopy ◽  
Contact Lens ◽  
Contact Lenses ◽  
Early Stage ◽  
Tap Water ◽  
Clinical Signs ◽  
Acanthamoeba Keratitis ◽  
Tertiary Hospital ◽  
Soft Contact Lenses ◽  
Number Of Patients

Abstract Background To report the clinical and microbiological features of Acanthamoeba keratitis (AK) related to contact lens use in a tertiary hospital in China. Methods In this retrospective study, the medical results of 61 cases of AK related to contact lens use from January 2000 to December 2017 were reviewed. The data included patients’ demographics, lens type, history, risk factors, disease stages, corneal scraping and culture reports, and treatments. Moreover, genotypic identification of some of the isolates was carried out with a PCR assay and sequence analysis of the 18S ribosomal DNA gene. Results There were 64 eyes included in the study. A total of 32.8% of the patients wore soft contact lenses, and 67.2% of patients used overnight orthokeratology. In the cases (20 eyes) in the early stage, 65% (13 eyes) had positive results according to Giemsa-stained smears, and 0.9% sodium chloride (NaCl) wet mounts revealed trophozoites in 7 eyes (35%). Six eyes (30%) were diagnosed by confocal microscopy combined with clinical signs. In the orthokeratology patients, 87.8% (36/41) rinsed their lenses and/or cases with tap water; 55% of soft-lens wearers wore their lenses while showering. The genotype of 9 isolates was determined, and all the strains belonged to genotype T4. In the orthokeratology group, the number of patients who required therapeutic penetrating keratoplasty after 2005 was less than that before 2005 (chi-square test, χ2 = 4.209, P = 0.04). Conclusions More than two-thirds of the cases were associated with orthokeratology. Examinations with Giemsa-stained smears, 0.9% NaCl wet mounts and confocal microscopy should be performed for patients who are highly suspected of having early-stage AK to help with early diagnosis. In the orthokeratology group, the rate of therapeutic keratoplasty after 2005 was less than that before 2005.

Chemical Constituents and Antiamoebic of Methanolic Fraction from Peperomia pellucida (Linn.)Kunth

2014 ◽  
Vol 709 ◽  
pp. 417-421
Author(s):  
Chanyapat Sangsuwon ◽  
Weena Jirujchariyakul ◽  
Kosol Roongruangchai
Keyword(s):  
Chemical Constituents ◽  
Acanthamoeba Keratitis ◽  
Spectroscopic Methods ◽  
Opportunistic Pathogens ◽  
Free Living ◽  
Methanol Fraction ◽  
Polyhexamethylene Biguanide ◽  
Causative Agents ◽  
Dye Staining ◽  
Good Hygiene

Acanthamoeba spp. is the free living protozoain the environment which are opportunistic pathogens of human [1]. Acanthamoeba spp. is the causative agents of Acanthamoeba keratitis (AK)[2]. The risks of AK increased by using contact lens are not good hygiene. Antiamoebic therapy were biguanides chlorhexidine (BCH) or polyhexamethylene biguanide (PHMB) which were not effective enough to kill Acanthamoeba cysts [3]. Reported, plant for protected glaucoma, anti-inflammatory and analgesic properties are Peperomiapellucida in Piperaceae family. This interesting of studied P. pellucida for antiamoebic. Dried plant of P. pellucida was chromatographic by Diaion HP20 and fractionated into methanol : water (1:1, FrI), methanol (FrII) and ethyl acetate (FrIII). The methanol fraction (FrII) was damaged morphological and changed structural of Acanthamoeba cysts, detected by toluidine dye staining are shown under the light microscope, in IC50 29.28±3.64%.The active methanol fraction was studied by chromatography, gave four fractionated fraction A1-A4. A1 led to the isolation of compounds 1, A2 and A3 isolated compounds 2-5. They were identified using spectroscopic methods.

scholarly journals Aminoglucoside/Imidazole in the Treatment of Acanthamoeba Keratitis

2018 ◽  
Vol 2 (2) ◽  
Keyword(s):  
Visual Acuity ◽  
Acanthamoeba Keratitis ◽  
Final Visual Acuity ◽  
Free Living ◽  
Corneal Infection ◽  
Free Living Amoeba

Acanthamoeba Keratitis (AK) is an infrequent corneal infection caused by free living amoeba, it is frequently misdiagnosed and medically/surgical treated with low or no response in advanced cases. In this paper we present five cases of AK with early diagnoses and good response to aminoglucoside/imidazole treatment and achieving acceptable final visual acuity in each case.

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