Acanthamoeba keratitis: improving the Scottish diagnostic service for the rapid molecular detection of 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.

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Genotyping of Acanthamoeba Species Isolated from Keratitis Patients by PCR Sequencing Methods in Tehran, Iran

International Journal of Medical Laboratory ◽

10.18502/ijml.v6i4.2002 ◽

2019 ◽

Author(s):

Tooran Nayeri Chegeni ◽

Fatemeh Ghaffarifar ◽

Majid Pirestani ◽

Fariba Khoshzaban ◽

Abdolhosein Dalimi Asl ◽

...

Keyword(s):

Contact Lenses ◽

Pcr Amplification ◽

Acanthamoeba Keratitis ◽

Local Alignment ◽

Sequencing Analysis ◽

Search Tool ◽

Skin Nodules ◽

Acanthamoeba Species ◽

Eye Clinic

Background and Aims: Amoebae of the genus Acanthamoeba are unicellular amphizoic opportunistic pathogens that may cause fatal granulomatous encephalitis, eye keratitis, amebic pneumonitis and skin nodules as well as abscesses in humans and animals. Acanthamoeba keratitis is caused by trauma to the eye, contaminated cleaning solutions and the use of contact lenses. The aim of the present study was to identify the genotypes of Acanthamoeba in all patients with a clinical diagnosis of Acanthamoeba keratitis referring to eye clinic in Tehran using polymerase chain reaction (PCR). Materials and Methods: In this study, samples were collected from 35 patients who had referred to the eye clinic and were cultured on 1.5% non-nutrient agar. DNA was extracted, and then PCR amplification was performed using genus specific primers. Sequencing analysis and basic local alignment search tool search were conducted to determine the genotypes. Phylogenetic tree was generated using maximum likely algorithm in phylogenetic program MEGA version 6. Results: Eight cases were positive for Acanthamoeba using genus specific primer pairs. All specimens were reported as genotype T4. Conclusions: Determination of genotypes showed all isolates belonging to genotype T4; this abundance may be due to its higher prevalence in the environment or its greater virulence. However, further analysis of clinical and environmental samples is necessary to clarify this property.

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18S Ribosomal DNA Typing and Tracking of Acanthamoeba Species Isolates from Corneal Scrape Specimens, Contact Lenses, Lens Cases, and Home Water Supplies of Acanthamoeba Keratitis Patients in Hong Kong

Journal of Clinical Microbiology ◽

10.1128/jcm.40.5.1621-1625.2002 ◽

2002 ◽

Vol 40 (5) ◽

pp. 1621-1625 ◽

Cited By ~ 134

Author(s):

G. C. Booton ◽

D. J. Kelly ◽

Y.-W. Chu ◽

D. V. Seal ◽

E. Houang ◽

...

Keyword(s):

Hong Kong ◽

Ribosomal Dna ◽

Contact Lenses ◽

Dna Typing ◽

Acanthamoeba Keratitis ◽

Water Supplies ◽

Acanthamoeba Species ◽

Corneal Scrape

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Investigating Domestic Shower Settings as a Risk Factor for Acanthamoeba Keratitis

Water ◽

10.3390/w12123493 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3493

Author(s):

Binod Rayamajhee ◽

Dinesh Subedi ◽

Seoyoung Won ◽

Jamie (Jung Yun) Kim ◽

Ajay Vijay ◽

...

Keyword(s):

Risk Factors ◽

Risk Factor ◽

Water Contamination ◽

18S Rrna ◽

Pcr Amplification ◽

Acanthamoeba Keratitis ◽

Domestic Water ◽

Online Questionnaire ◽

Hygiene Practices ◽

Acanthamoeba Species

Acanthamoeba keratitis (AK) is a sight-threatening infection of the cornea, which is caused by soil and the waterborne protist Acanthamoeba spp. AK most commonly occurs during contact lens (CL) wear. Risk factors for AK have been linked to non-optimal lens hygiene practices and Acanthamoeba contamination of domestic water. This study investigated the prevalence of Acanthamoeba species in domestic showers in the greater Sydney region, as well as the perception of water contamination of CL as being a risk factor for AK among previous AK patients and their family and friends. Samples from four locations of 13 participants’ shower areas were cultured and Acanthamoeba 18S rRNA was amplified by PCR, followed by sequencing. Twenty-six responses were received to the online questionnaire. Fifteen water samples (29%, 15/52) contained amoeba that were morphologically classified as Acanthamoeba spp. PCR amplification confirmed the presence of Acanthamoeba spp. in four samples (8%, 4/52). Three isolates belonged to the T4, and one isolate to the T3 genotype. On the questionnaire survey, 96% (25/26) of respondents believed that water contamination was likely to be a risk factor for Acanthamoeba keratitis and 58% rated showering with CL as ‘extremely likely’ to be a risk factor for AK. Acanthamoeba pathogenic genotypes (T3 and T4) in the domestic bathroom water suggest that clinicians should remain vigilant in educating CL wearers about avoiding domestic water contamination of CL.

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Acanthamoeba spp. in river water samples from the Black Sea region, Turkey

Journal of Water and Health ◽

10.2166/wh.2020.170 ◽

2020 ◽

Vol 18 (2) ◽

pp. 186-199 ◽

Cited By ~ 1

Author(s):

İlknur Koyun ◽

Zeynep Kolören ◽

Ülkü Karaman ◽

Amalia Tsiami ◽

Panagiotis Karanis

Keyword(s):

Black Sea ◽

Water Samples ◽

Tap Water ◽

Acanthamoeba Keratitis ◽

The Black Sea ◽

Free Living ◽

Black Sea Region ◽

River Waters ◽

Free Living Amoeba ◽

Acanthamoeba Species

Abstract The present study aims to investigate the occurrence of free living amoeba (FLA) in water resources (rivers and tap water) in Samsun in the Black Sea. The presence of Acanthamoeba spp. was confirmed in 98 of 192 water samples collected from 32 sites of Samsun province (Samsun centre, Terme, Carsamba, Tekkekoy, Bafra) by PCR. Acanthamoeba spp. were found in 15/36 river samples from Samsun, in 58/90 from Terme, in 12/30 from Carsamba, in 7/18 from Tekkekoy and in 6/18 from Bafra. No Acanthamoeba species were detected in tap water samples. The highest rate in river waters contaminated with Acanthamoeba species was in Terme followed by Samsun centre (41.7%), Carsamba (40%), Tekkekoy (38.9%) and Bafra districts (33.3%), respectively. The result of the subsequent sequence analysis showed Haplotype I (A. triangularis) in 5%, Haplotype II (A. polyphaga) in 29.6%, Haplotype III (Acanthamoeba spp.) in 62% and Haplotype IV (A. lenticulata) in 3%. The most common genotype was Acanthamoeba T4 (Acanthamoeba spp., A. polyphaga, A. triangularis) and T5 genotype was also found in 3%. The T4 genotype is the most common genotype associated with Acanthamoeba keratitis (AK) worldwide; therefore, humans and animals living in the area are at risk after contact with such waters.

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Evaluation of Amebicidal and Cysticidal Activities of Antifungal Drug Isavuconazonium Sulfate against Acanthamoeba T4 Strains

Pharmaceuticals ◽

10.3390/ph14121294 ◽

2021 ◽

Vol 14 (12) ◽

pp. 1294

Author(s):

Brian Shing ◽

Mina Balen ◽

Anjan Debnath

Keyword(s):

Invasive Aspergillosis ◽

Acanthamoeba Keratitis ◽

Antagonistic Effect ◽

Antifungal Drug ◽

Corneal Infection ◽

Human Eye ◽

Polyhexamethylene Biguanide ◽

Amebicidal Activity ◽

Acanthamoeba Species

Acanthamoeba species of amebae are often associated with Acanthamoeba keratitis, a severe corneal infection. Isavuconazonium sulfate is an FDA-approved drug for the treatment of invasive aspergillosis and mucormycosis. This prodrug is metabolized into the active isavuconazole moiety. Isavuconazole was previously identified to have amebicidal and cysticidal activity against Acanthamoeba T4 strains, but the activity of its prodrug, isavuconazonium sulfate, against trophozoites and cysts remains unknown. Since it is not known if isavuconazonium can be metabolized into isavuconazole in the human eye, we evaluated the activities of isavuconazonium sulfate against trophozoites and cysts of three T4 genotype strains of Acanthamoeba. Isavuconazonium displayed amebicidal activity at nanomolar concentrations as low as 1.4 nM and prevented excystation of cysts at concentrations as low as 136 μM. We also investigated the cysticidal activity of isavuconazonium sulfate in combination with a currently used amebicidal drug polyhexamethylene biguanide (PHMB). Although combination of isavuconazonium with PHMB did not elicit an obvious synergistic cysticidal activity, the combination did not cause an antagonistic effect on the cysts of Acanthamoeba T4 strains. Collectively, these findings suggest isavuconazonium retains potency against Acanthamoeba T4 strains and could be adapted for Acanthamoeba keratitis treatment.

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Acanthamoeba Keratitis and Acanthamoeba Conjunctivitis: A Case Report

Iranian Journal of Parasitology ◽

10.18502/ijpa.v15i2.3311 ◽

2020 ◽

Author(s):

Oktay ALVER ◽

Mehmet BAYKARA ◽

Merve YÜRÜK ◽

Nazmiye ÜLKÜ TÜZEMEN

Keyword(s):

Visual Loss ◽

Contact Lenses ◽

Acanthamoeba Keratitis ◽

Eyelid Edema ◽

History Of ◽

Laboratory Examinations ◽

Acanthamoeba Species ◽

Eye Infection ◽

The Right ◽

Microbial Agents

Acanthamoeba species are vision-threatening agents by causing cornea infections known as Acanthamoeba keratitis. A 5 year-old kid with the complaints of erythema, eyelid edema, inflammation, limitation of eye movements in the right eye, and having no history of wearing contact lenses or trauma, was diagnosed of Acanthamoeba conjunctivitis through laboratory examinations in the Ophthalmology clinic. The visual sharpness of the patient improved after the treatment. A 44 year-old female patient suffering from pain, stinging, irritation, and inability to see in the left eye with the history of wearing contact lenses or trauma was diagnosed of Acanthamoeba keratitis through laboratory examinations. The agent was isolated and identified as "A. castellani" in the Genotype "T2". Examination of the left eye on the 15th day of treatment indicated that all complaints disappeared except for the cataract originated visual loss. However, the first diagnosis of Acanthamoeba keratitis appeared in the literature on a case with no history of wearing contact lenses and trauma it is found to be attention grabbing. We think that Acanthamoeba should not be ignored among microbial agents that cause eye infection with or without trauma and contact lens usage history.

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