3,220 results on '"ACANTHAMOEBA keratitis"'
Search Results
2. Parasitic Ulcer Treatment Trial (PUTT)
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Johns Hopkins University, Oregon Health and Science University, University of Illinois at Chicago, University of Michigan, University of California, Los Angeles, University of Miami, University of Pennsylvania, Columbia University, University of Iowa, University of Florida, Aravind Eye Care System, Moorfields Eye Hospital NHS Foundation Trust, Federal University of São Paulo, National Eye Institute (NEI), and Jeremy Keenan, MD, MPH, Professor of Ophthalmology/Director of International Programs at the Proctor Foundation
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- 2024
3. Rose Bengal Electromagnetic Activation With Green Light for Infection Reduction (REAGIR)
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Aravind Eye Care System, National Eye Institute (NEI), Stanford University, and Federal University of São Paulo
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- 2024
4. Acanthamoeba and Artificial Intelligence
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Giulio Ferrari, Professor of Ophthalmology-San Raffaele Vita Salute University, Cornea and Ocular Surface Unit; Head-Eye Repair Lab San Raffaele Scientific Institute
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- 2024
5. Amoebicidal and cysticidal in vitro activity of cationic dendritic molecules against Acanthamoeba polyphaga and Acanthamoeba griffini.
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Verdú-Expósito, Cristina, Martín-Pérez, Tania, Pérez-Serrano, Jorge, Sanchez-Nieves, Javier, de la Mata, Francisco Javier, and Heredero-Bermejo, Irene
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DENDRIMERS , *ACANTHAMOEBA keratitis , *LIFE cycles (Biology) , *CYTOTOXINS , *HELA cells - Abstract
Acanthamoeba species are responsible for serious human infections, including Acanthamoeba keratitis (AK) and granulomatous amoebic encephalitis (GAE). These pathogens have a simple life cycle consisting of an infective trophozoite stage and a resistant cyst stage, with cysts posing significant treatment challenges due to their resilience against harsh conditions and chemical agents. Current treatments for AK often involve combining diamines, such as propamidine, and biguanides, such as chlorhexidine (CLX), which exhibit limited efficacy and significant toxicity. Thus, the effect of new therapeutic molecules, such as multifunctional systems (e.g., carbosilane dendritic molecules), should be studied as potential alternatives due to their biocidal properties and lower toxicity. This study evaluates various dendritic compounds against trophozoites and cysts of two Acanthamoeba clinical isolates, both alone and in combination with CLX, and assesses their cytotoxicity on HeLa cells. The results indicated that certain dendritic compounds, especially BDSQ024, were effective against both trophozoites and cysts. Additionally, combinations of dendritic molecules and CLX showed enhanced efficacy in eliminating trophozoites and cysts, suggesting potential for synergistic treatments. The study underscores the promise of dendritic molecules in developing more effective and less toxic therapies for Acanthamoeba infections. [ABSTRACT FROM AUTHOR]
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- 2024
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6. The in vitro effect riboflavin combined with or without UVA in Acanthamoeba castellanii.
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Park, Joohee and Park, Choul Yong
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ACANTHAMOEBA castellanii , *ACANTHAMOEBA keratitis , *REACTIVE oxygen species , *GENETIC transcription , *VITAMIN B2 , *ACANTHAMOEBA - Abstract
The anti-Acanthamoeba properties of riboflavin and its enhanced amoebicidal effects when combined with ultraviolet A (UVA) radiation were investigated in vitro. The viability of cultured Acanthamoeba castellanii was assessed by adding varying concentrations (0 ~ 0.2% w/v) of riboflavin to the culture medium or after combined riboflavin and UVA treatment (30 min, 3 mW/cm2) over 1, 3, 5, and 7 days. Intracellular reactive oxygen species (ROS) levels were measured following a 30-minute exposure to riboflavin. Additionally, the cysticidal effects of riboflavin, UVA, and their combination were evaluated. Gene transcription in Acanthamoeba was analyzed using RNA-seq. Riboflavin demonstrated dose-dependent toxicity on Acanthamoeba, accompanied by an increase in intracellular ROS. Exposure to 0.2% riboflavin reduced Acanthamoeba viability by over 50% within one day. UVA treatment alone also reduced viability by over 50%. Combined treatment with 0.2% riboflavin decreased trophozoite survival by more than 80%, and approximately 60% of cysts were killed when 0.1% riboflavin was combined with UVA. RNA-seq analysis indicated significant changes in gene expression after exposure to riboflavin, UVA, and their combination, particularly affecting oxidoreductase activity, cystathionine β synthase, and serine-threonine kinase activity. These findings indicate that riboflavin exhibits dose-dependent toxicity in Acanthamoeba, primarily through increased ROS generation. Combining riboflavin and UVA did not fully eradicate trophozoites and cysts of Acanthamoeba, but was able to partially inactivate them. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Identification of essential genes for Acanthamoeba castellanii excystation during encystation and excystation.
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Kim, Min-Jeong, Jo, Hye-Jeong, Quan, Fu-Shi, Chu, Ki Back, Kong, Hyun-Hee, and Moon, Eun-Kyung
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ACANTHAMOEBA castellanii ,SMALL interfering RNA ,GENE expression ,LIFE cycles (Biology) ,ACANTHAMOEBA keratitis - Abstract
Acanthamoeba is an opportunistic pathogen that causes Acanthamoeba keratitis, granulomatous amoebic encephalitis, and other cutaneous diseases. The life cycle of Acanthamoeba consists of 2 stages of trophozoites and cysts. Under adverse environmental conditions, Acanthamoeba encysts, while the conditions become favorable for growth, it reverts to the trophozoite form. Acanthamoeba excystation is crucial for its proliferation and can lead to recurrent infections after incomplete treatment. To identify the factors involved in excystation, A. castellanii was subjected to either encystation- or excystation-inducing conditions, and gene expression profiles were compared using mRNA sequencing. A. castellanii samples were collected at 8 h intervals for analysis under both conditions. Differentially expressed gene analysis revealed that 1,214 and 1,163 genes were upregulated and downregulated, respectively, by more than 2-fold during early excystation. Five genes markedly upregulated in early excystation (ACA1_031140, ACA1_032330, ACA1_374400, ACA1_275740, and ACA1_112650) were selected, and their expression levels were confirmed via real-time PCR. Small interfering RNA (siRNA) targeting these 5 genes was transfected into Acanthamoeba and gene knockdown was validated through real-time PCR. The silencing of ACA1_031140, ACA1_032330, ACA1_374400, and ACA1_112650 inhibited excystation and suggested that these genes might be essential for excystation. Our findings provide valuable insights for suppressing Acanthamoeba proliferation and recurrence. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Oxford Nanopore Technology-Based Identification of an Acanthamoeba castellanii Endosymbiosis in Microbial Keratitis.
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Scharf, Sebastian Alexander, Friedrichs, Lennart, Bock, Robert, Borrelli, Maria, MacKenzie, Colin, Pfeffer, Klaus, and Henrich, Birgit
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ACANTHAMOEBA keratitis ,WHOLE genome sequencing ,ACANTHAMOEBA castellanii ,EYE infections ,DISEASE progression - Abstract
(1) Background: Microbial keratitis is a serious eye infection that carries a significant risk of vision loss. Acanthamoeba spp. are known to cause keratitis and their bacterial endosymbionts can increase virulence and/or treatment resistance and thus significantly worsen the course of the disease. (2) Methods and Results: In a suspected case of Acanthamoeba keratitis, in addition to Acanthamoeba spp., an endosymbiont of acanthamoebae belonging to the taxonomic order of Holosporales was detected by chance in a bacterial 16S rDNA-based pan-PCR and subsequently classified as Candidatus Paracaedibacter symbiosus through an analysis of an enlarged 16S rDNA region. We used Oxford Nanopore Technology to evaluate the usefulness of whole-genome sequencing (WGS) as a one-step diagnostics method. Here, Acanthamoeba castellanii and the endosymbiont Candidatus Paracaedibacter symbiosus could be directly detected at the species level. No other microbes were identified in the specimen. (3) Conclusions: We recommend the introduction of WGS as a diagnostic approach for keratitis to replace the need for multiple species-specific qPCRs in future routine diagnostics and to enable an all-encompassing characterisation of the polymicrobial community in one step. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Isolation and molecular characterization of Acanthamoeba spp. from Iraqi patients with Keratitis.
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Aldin, Muna B., Ardalan, Naksheen M., and Jassim, Khudair Abbas
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ACANTHAMOEBA keratitis ,CONTACT lenses ,EYE infections ,IRAQIS ,NUCLEIC acids - Abstract
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- 2024
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10. Potentially Pathogenic Free-Living Amoebae Isolated from Soil Samples from Warsaw Parks and Squares.
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Hendiger-Rizo, Edyta Beata, Chmielewska-Jeznach, Magdalena, Poreda, Katarzyna, Rizo Liendo, Aitor, Koryszewska-Bagińska, Anna, Olędzka, Gabriela, and Padzik, Marcin
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ACANTHAMOEBA keratitis ,HUMAN settlements ,SOIL sampling ,ACANTHAMOEBA ,AMEBIASIS - Abstract
Free-living amoebae (FLA) are prevalent in diverse environments, representing various genera and species with different pathogenicity. FLA-induced infections, such as the highly fatal amoebic encephalitis, with a mortality rate of 99%, primarily affect immunocompromised individuals while others such as Acanthamoeba keratitis (AK) and cutaneous amebiasis may affect immunocompetent individuals. Despite the prevalence of FLA, there is a lack of standardized guidelines for their detection near human habitats. To date, no studies on the isolation and identification of FLA in environmental soil samples in Warsaw have been published. The aim of this study was to determine the presence of amoebae in soil samples collected from Warsaw parks and squares frequented by humans. The isolated protozoa were genotyped. Additionally, their pathogenic potential was determined through thermophilicity tests. A total of 23 soil samples were seeded on non-nutrient agar plates (NNA) at 26 °C and monitored daily for FLA presence. From the total of 23 samples, 18 were positive for FLA growth in NNA and PCR (78.2%). Acanthamoeba spp. was the most frequently isolated genus, with a total of 13 positive samples (13/18; 72.2%), and the T4 genotype being the most common. Moreover, Platyamoeba placida (3/18; 16.7%), Stenamoeba berchidia (1/18; 5.6%) and Allovahlkampfia sp. (1/18; 5.6%), also potentially pathogenic amoebae, were isolated. To our knowledge, this is the first report of FLA presence and characterization in the Warsaw area. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Steroids in the Management of Infectious Keratitis.
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Keenan, Jeremy
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Humans ,Acanthamoeba Keratitis ,Corneal Ulcer ,Keratitis ,Herpetic ,Adrenal Cortex Hormones ,Glucocorticoids ,Eye Infections ,Bacterial ,Steroids ,Anti-Bacterial Agents - Abstract
PURPOSE: To summarize the evidence base on the use of topical corticosteroids for infectious keratitis. METHODS: Narrative review. RESULTS: Infectious keratitis is a painful condition that often results in visually significant corneal stromal scarring, even when antimicrobial therapy is successful. Corticosteroids may reduce inflammation and subsequent scar formation and while relieving the acute ocular pain associated with a corneal ulcer. However, corticosteroids also reduce the host immune response, which could hinder the ability to clear infection. The safety and effectiveness of corticosteroids depends to a large part on the efficacy of the antimicrobials being used to treat the underlying infection. Randomized trials have found that corticosteroids are safe and effective for herpetic keratitis when used with appropriate antiviral therapy, and are safe for bacterial keratitis when used with broad spectrum topical antibiotics. The effectiveness of corticosteroids for bacterial keratitis has not been shown conclusively, although more advanced bacterial corneal ulcers may do better with corticosteroids. No randomized trials have assessed the safety and effectiveness of steroids for fungal or acanthamoeba keratitis. Animal studies suggest corticosteroids may be harmful in fungal keratitis, and observational human studies have found that steroids are harmful for fungal and acanthamoeba keratitis when started prior to anti-amoebics. CONCLUSIONS: Topical corticosteroids, when used as an adjunct to antimicrobial therapy, may be beneficial if the antimicrobial being used can effectively clear or suppress the infection, such as in bacterial and herpetic keratitis. Randomized trials would be helpful to further delineate the role of corticosteroids for infectious keratitis.
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- 2023
12. Parasitic Ulcer Treatment Trial Pilot
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Research to Prevent Blindness
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- 2024
13. Infectious Keratitis in Patients Over 65: A Review on Treatment and Preserving Eyesight
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Kim CK, Karslioglu MZ, Zhao SH, and Lee OL
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aging ,inflammaging ,bacterial keratitis ,viral keratitis ,fungal keratitis ,acanthamoeba keratitis ,Geriatrics ,RC952-954.6 - Abstract
Christine K Kim,1 Melisa Z Karslioglu,1 Sharon H Zhao,2 Olivia L Lee1 1Gavin Herbert Eye Institute, University of California, Irvine School of Medicine, Irvine, CA, USA; 2Feinberg School of Medicine, Northwestern University, Chicago, IL, USACorrespondence: Olivia L Lee, Gavin Herbert Eye Institute, University of California Irvine School of Medicine, 850 Health Sciences Road, Irvine, CA, 92617, USA, Tel +1 949 824 0573, Email leeol@hs.uci.eduAbstract: Infectious keratitis (IK) represents a significant global health concern, ranking as the fifth leading cause of blindness worldwide despite being largely preventable and treatable. Elderly populations are particularly susceptible due to age-related changes in immune response and corneal structure. However, research on IK in this demographic remains scarce. Age-related alterations such as increased permeability and reduced endothelial cell density further compound susceptibility to infection and hinder healing mechanisms. Additionally, inflammaging, characterized by chronic inflammation that develops with advanced age, disrupts the ocular immune balance, potentially exacerbating IK and other age-related eye diseases. Understanding these mechanisms is paramount for enhancing IK management, especially in elderly patients. This review comprehensively assesses risk factors, clinical characteristics, and management strategies for bacterial, viral, fungal, and acanthamoeba keratitis in the elderly population, offering crucial insights for effective intervention.Keywords: aging, inflammaging, bacterial keratitis, viral keratitis, fungal keratitis, acanthamoeba keratitis
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- 2024
14. Use of in vivo confocal microscopy in suspected Acanthamoeba keratitis: a 12-year real-world data study at a Swedish regional referral center.
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Toba, Bogdana and Lagali, Neil
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ACANTHAMOEBA keratitis , *CONFOCAL microscopy , *DENDRITIC cells , *VISUAL acuity , *THERAPEUTICS - Abstract
Purpose: To report real-world data (RWD) on the use of in vivo confocal microscopy (IVCM) in handling cases of suspected Acanthamoeba keratitis (AK) cases at a regional referral center during a 12-year period. Methods: Retrospective study of patients with suspected AK presenting at a regional referral center for IVCM in Sweden from 2010 to 2022. Demographics, symptoms, outcomes, and clinical management were analyzed, and IVCM images were interpreted. Results: Of 74 included patients with suspected AK, 18 (24%) were IVCM-positive, 33 (44%) were IVCM-negative, 15 had inconclusive IVCM results (20.2%), and 8 (11%) were referred for a second opinion based on IVCM, 4 of which were IVCM-positive (5.5%), yielding an overall IVCM-positive rate of 29.5%. Cultures were taken in 38 cases (51%) with only 2 cases (2.7%) culture-positive for AK. Of IVCM-negative cases, cultures were taken in 22 (67%) of cases and 100% of these were AK-negative. IVCM-positive cases had more clinic visits (median 30, P = 0.018) and longer follow-up time (median 890 days, P = 0.009) than IVCM-negative patients, while visual acuity improvement did not differ (P > 0.05). Of IVCM-positive cases, 10 (56%) underwent surgery despite prior anti-amoebic treatment, and 14 (78%) had 3 or more IVCM examinations during follow-up, with cysts (100%), dendritic cells (89%) and inflammatory infiltrate (67%) as the most prevalent features. Longitudinal IVCM indicated improvement in cysts, dendritic cells and subbasal nerves with treatment, while clinical resolution was not always consistent with complete absence of cysts. Conclusions: In a real-world setting, IVCM has a high reliability in classifying AK-negative cases, while IVCM detects AK-positive cases more frequently than the gold-standard culture method, leading to its preferential use over the culture method where time or resources are limited. Despite this, a subset of cases are IVCM-inconclusive, the clinical course of referred patients is long requiring many hospital visits, and visual acuity in most cases does not improve with medical treatment alone. Information sharing across centers and standardization of referral and diagnostic routines is needed to exploit the full potential of IVCM in AK patient management. [ABSTRACT FROM AUTHOR]
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- 2024
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15. Non-Contact-Lens-Related Acanthamoeba Keratitis Caused by Acanthamoeba sp. Group T4D/T4e.
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Vander Eecken, Morgane, Messiaen, Anne-Sophie, Hamerlinck, Hannelore, Vandendriessche, Stien, Boelens, Jerina, and Roels, Dimitri
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ACANTHAMOEBA keratitis , *ACANTHAMOEBA , *KERATITIS , *SYMPTOMS , *CORNEA surgery - Abstract
Acanthamoeba keratitis (AK) is a rare but serious infection of the cornea, typically associated with contact lens wear. Here, we present a case of AK caused by the Acanthamoeba genotype T4D/T4e in a patient without identifiable risk factors: a 34-year-old woman who initially presented with signs and symptoms suggestive of herpetic keratitis, and who did not respond to conventional treatment. Corneal culture and targeted metagenomic analysis (18S rRNA, 16S-like rRNA) revealed the presence of an Acanthamoeba species closely related to the 'Nagington' strain. Despite intensive anti-Acanthamoeba therapy, complications arose necessitating penetrating keratoplasty. In conclusion, this case underscores the importance of considering Acanthamoeba as a causal agent of keratitis in non-contact-lens wearers. The identification of Acanthamoeba genotype T4D/T4e challenges the previous understanding of its pathogenic potential. Furthermore, it emphasizes the need for ongoing research into the pathogenicity of different Acanthamoeba subtypes. Early diagnosis and treatment are essential for preventing vision-threatening complications associated with AK. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Strathclyde minor groove binders (S-MGBs) with activity against Acanthamoeba castellanii.
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Mcgee, Leah M C, Sanchez, Alemao G Carpinteyro, Perieteanu, Marina, Eskandari, Kaveh, Bian, Yan, Mackie, Logan, Young, Louise, Beveridge, Rebecca, Suckling, Colin J, Roberts, Craig W, and Scott, Fraser J
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ACANTHAMOEBA castellanii , *ACANTHAMOEBA keratitis , *ANTI-infective agents , *CYTOTOXINS , *TRYPANOSOMA brucei - Abstract
Background Acanthamoeba spp. is the causative agent of Acanthamoeba keratitis and granulomatous amoebic encephalitis. Strathclyde minor groove binders (S-MGBs) are a promising new class of anti-infective agent that have been shown to be effective against many infectious organisms. Objectives To synthesize and evaluate the anti- Acanthamoeba activity of a panel of S-MGBs, and therefore determine the potential of this class for further development. Methods A panel of 12 S-MGBs was synthesized and anti- Acanthamoeba activity was determined using an alamarBlue™-based trophocidal assay against Acanthamoeba castellanii. Cross-screening against Trypanosoma brucei brucei , Staphylococcus aureus and Escherichia coli was used to investigate selective potency. Cytotoxicity against HEK293 cells allowed for selective toxicity to be measured. DNA binding studies were carried out using native mass spectrometry and DNA thermal shift assays. Results and discussion S-MGB-241 has an IC50 of 6.6 µM against A. castellanii , comparable to the clinically used miltefosine (5.6 µM) and negligible activity against the other organisms. It was also found to have an IC50 > 100 µM against HEK293 cells, demonstrating low cytotoxicity. S-MGB-241 binds to DNA as a dimer, albeit weakly compared to other S-MGBs previously studied. This was confirmed by DNA thermal shift assay with a Δ T m = 1 ± 0.1°C. Conclusions Together, these data provide confidence that S-MGBs can be further optimized to generate new, potent treatments for Acanthameoba spp. infections. In particular, S-MGB-241, has been identified as a 'hit' compound that is selectively active against A. castellanii , providing a starting point from which to begin optimization of DNA binding and potency. [ABSTRACT FROM AUTHOR]
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- 2024
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17. The incidence of severe complications in acanthamoeba keratitis: Qualitative and quantitative systematic assessment.
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Posarelli, Matteo, Passaro, Maria Laura, Avolio, Fabio Claudio, Costagliola, Ciro, Semeraro, Francesco, and Romano, Vito
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ACANTHAMOEBA keratitis , *CORNEAL transplantation , *CORNEA injuries , *CORNEA surgery , *KERATITIS - Abstract
Acanthamoeba keratitis (AK) is a rare, sight-threating corneal infection. The disease is challenging to diagnose and treat, and the amoeba can rapidly encyst, persisting in the tissue and causing recurrences. Medical therapy is conventionally considered the first line treatment, but advanced cases could require more invasive treatments like a "chaud" corneal transplant. We review the incidence of severe complications in patients affected by AK. Of 439 reports screened, 158 met our inclusion criteria. Incidence of severe complications was low, with 2.21 % patients developing perforation, 1 % requiring evisceration/enucleation and less than 1 % developing endophthalmitis. Corneal transplantation was required in 16.68 % of the cases. According to our results, and considering the reported incidences of these complications in other infectious keratitis, AK patients have an overall low risk of developing perforation, endophthalmitis, and enucleation/evisceration. Nevertheless, data available in the literature remain poor, and further randomized control trials are needed to confirm our findings. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Rethinking Keratoplasty for Patients with Acanthamoeba Keratitis: Early "Low Load Keratoplasty" in Contrast to Late Optical and Therapeutic Keratoplasty.
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Abu Dail, Yaser, Flockerzi, Elias, Munteanu, Cristian, Szentmáry, Nóra, Seitz, Berthold, and Daas, Loay
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ACANTHAMOEBA keratitis ,GRAFT survival ,CORNEA surgery ,VISUAL acuity ,SURVIVAL rate - Abstract
Background: Early therapeutic penetrating keratoplasty (TKP) for Acanthamoeba keratitis (AK) is thought to have a worse visual prognosis than the delayed optical penetrating keratoplasty (OKP) after successful conservative treatment of AK. This has led to a tendency to prolong conservative therapy and delay penetrating keratoplasty in patients with AK. This retrospective series presents the results of patients with AK that underwent early penetrating keratoplasty after reducing the corneal amoeba load through intensive conservative therapy, so-called "low load keratoplasty" (LLKP). Patients and methods: The medical records of our department were screened for patients with AK, confirmed by histological examination and/or PCR and/or in vivo confocal microscopy, which underwent ab LLKP and had a follow-up time of at least one year between 2009 and 2023. Demographic data, best corrected visual acuity (BCVA) and intraocular pressure at first and last visit, secondary glaucoma (SG), and recurrence and graft survival rates were assessed. Results: 28 eyes of 28 patients were included. The average time from initiation of therapy to penetrating keratoplasty (PKP) was 68 ± 113 days. The mean follow-up time after LLKP was 53 ± 42 months. BCVA (logMAR) improved from 1.9 ± 1 pre-operatively to 0.5 ± 0.6 at last visit (p < 0.001). A total of 14% of patients were under medical therapy for SG at the last visit, and two of them underwent glaucoma surgery. The recurrence rate was 4%. The Kaplan–Meier graft survival rate of the first graft at four years was 70%. The second graft survival rate at four years was 87.5%. Conclusion: LLKP appears to achieve a good visual prognosis with an earlier visual and psychological habilitation, as well as low recurrence and SG rates. These results should encourage us to reconsider the optimal timing of PKP in therapy-resistant AK. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Iris setosa Pall. ex Link Extract Reveals Amoebicidal Activity against Acanthamoeba castellanii and Acanthamoeba polyphaga with Low Toxicity to Human Corneal Cells.
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Lê, Hương Giang, Hwang, Buyng Su, Choi, Ji-Su, Jeong, Yong Tae, Kang, Jung-Mi, Võ, Tuấn Cường, Oh, Young Taek, and Na, Byoung-Kuk
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ACANTHAMOEBA castellanii ,APOPTOSIS ,ACANTHAMOEBA keratitis ,IRIS (Eye) ,ACANTHAMOEBA - Abstract
Acanthamoeba keratitis (AK) is a sight-threatening and difficult-to-treat ocular infection. The significant side effects of current AK treatments highlight the urgent need to develop a safe and effective AK medication. In this study, the amoebicidal activity of Iris setosa Pall. ex Link extract (ISE) against Acanthamoeba was examined and its specific amoebicidal mechanism was explored. ISE induced significant morphological changes in Acanthamoeba trophozoites and exhibited amoebicidal activity against A. castellanii and A. polyphaga. ISE was further fractionated into five subfractions by sequential extraction with n-hexane, chloroform, ethyl acetate, n-butanol, and water, and their amoebicidal activities and underlying amoebicidal mechanisms were investigated. The n-butanol subfraction of ISE (ISE-BuOH) displayed selective amoebicidal activity against the Acanthamoeba species with minimal cytotoxicity in human corneal cells (HCE-2). ISE-BuOH triggered apoptosis-like programmed cell death (PCD) in amoebae, characterized by DNA fragmentation, increased ROS production, and caspase-3 activity elevation. ISE-BuOH also demonstrated a partial cysticidal effect against the amoeba species. ISE-BuOH could be a promising candidate in the development of therapeutic drugs for AK. [ABSTRACT FROM AUTHOR]
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- 2024
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20. Direct Cost Analysis of Microbial Keratitis in North China: A Hospital-Based Retrospective Study.
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Shi, Qingquan, Peng, Bo, Cheng, Zhen, Zhang, Zijun, Wei, Zhenyu, Wang, Zhiqun, Zhang, Yang, Chen, Kexin, Xu, Xizhan, Lu, Xinxin, Cao, Kai, Wei, Xueyao, and Liang, Qingfeng
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ACANTHAMOEBA keratitis ,FUNGAL keratitis ,COST analysis ,CORNEAL ulcer ,DIRECT costing - Abstract
Microbial keratitis (MK) is the fourth leading cause of blindness globally, imposing a substantial burden on the healthcare system. This study aims to determine the cost composition of MK patients and explore factors influencing these expenses. We analyzed the demographics, clinical features, and costs of 602 MK patients treated at Beijing Tongren Hospital from June 2021 to October 2023. The analysis revealed the average total cost of treating MK was USD 1646.8, with a median of USD 550.3 (IQR: 333.3–1239.1). Patients with Acanthamoeba keratitis (AK) incurred the highest median total costs at USD 706.2 (IQR: 399.2–3370.2). Additionally, AK patients faced the highest costs for ophthalmic exams and laboratory tests (both p < 0.001), while patients with fungal keratitis (FK) and viral keratitis (VK) experienced higher medication costs. Costs varied significantly with the severity of MK, especially for outpatients at severity level 4, which was markedly higher than levels 1–3 (USD 1520.1 vs. USD 401.0, p < 0.001). Delayed presentation also resulted in increased costs (USD 385.2 vs. USD 600.3, p < 0.001). Our study highlights the financial burden associated with MK treatment and underscores the importance of timely and accurate diagnosis and intervention. [ABSTRACT FROM AUTHOR]
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- 2024
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21. Acanthamoeba keratitis: new hopes for potential interventions for a curable but often refractory disease.
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Alawfi, Bader Saleem, Khan, Naveed Ahmed, Lloyd, David, and Siddiqui, Ruqaiyyah
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ACANTHAMOEBA keratitis ,NANOMEDICINE ,CONTACT lenses ,EARLY diagnosis ,DISEASE relapse ,PHOTODYNAMIC therapy - Abstract
Introduction: Often associated with contact lens wear, Acanthamoeba keratitis is an extremely painful blinding infection that has remained significant despite advances in drug discovery and chemotherapies. Current treatment is intricate and demands early diagnosis, aggressive and prolonged application, and may result in infection recurrence. The latter is due to the ability of the parasite to undergo cellular differentiation and transform into a resistant cyst form or infective trophozoite form. Areas covered: Here, we present a review of our current understanding of emerging therapies and priorities tackling Acanthamoeba keratitis. Literature searches were carried out using bibliographic databases and results sifted and reviewed to present recent findings, challenges and novel opportunities in the development of therapeutic interventions and/or preventative measures against Acanthamoeba keratitis. Expert opinion: Nanomedicine-based theranostics to combine diagnosis and treatment of Acanthamoeba keratitis offer remarkable opportunity in the development of clinical applications in the management of Acanthamoeba keratitis. [ABSTRACT FROM AUTHOR]
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- 2024
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22. Deep learning for multi-type infectious keratitis diagnosis: A nationwide, cross-sectional, multicenter study.
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Li, Zhongwen, Xie, He, Wang, Zhouqian, Li, Daoyuan, Chen, Kuan, Zong, Xihang, Qiang, Wei, Wen, Feng, Deng, Zhihong, Chen, Limin, Li, Huiping, Dong, He, Wu, Pengcheng, Sun, Tao, Cheng, Yan, Yang, Yanning, Xue, Jinsong, Zheng, Qinxiang, Jiang, Jiewei, and Chen, Wei
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PREDICTIVE tests ,CROSS-sectional method ,PREDICTION models ,RECEIVER operating characteristic curves ,DATA analysis ,RESEARCH funding ,ACANTHAMOEBA keratitis ,BACTERIAL keratitis ,RESEARCH evaluation ,DESCRIPTIVE statistics ,FUNGAL keratitis ,EYE examination ,COMPUTER-aided diagnosis ,DEEP learning ,RESEARCH ,STATISTICS ,KERATITIS ,CONFIDENCE intervals ,DIGITAL image processing ,ALGORITHMS ,EVALUATION - Abstract
The main cause of corneal blindness worldwide is keratitis, especially the infectious form caused by bacteria, fungi, viruses, and Acanthamoeba. The key to effective management of infectious keratitis hinges on prompt and precise diagnosis. Nevertheless, the current gold standard, such as cultures of corneal scrapings, remains time-consuming and frequently yields false-negative results. Here, using 23,055 slit-lamp images collected from 12 clinical centers nationwide, this study constructed a clinically feasible deep learning system, DeepIK, that could emulate the diagnostic process of a human expert to identify and differentiate bacterial, fungal, viral, amebic, and noninfectious keratitis. DeepIK exhibited remarkable performance in internal, external, and prospective datasets (all areas under the receiver operating characteristic curves > 0.96) and outperformed three other state-of-the-art algorithms (DenseNet121, InceptionResNetV2, and Swin-Transformer). Our study indicates that DeepIK possesses the capability to assist ophthalmologists in accurately and swiftly identifying various infectious keratitis types from slit-lamp images, thereby facilitating timely and targeted treatment. [ABSTRACT FROM AUTHOR]
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- 2024
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23. Clinical Profile and Demographic Distribution of Acanthamoeba Keratitis: An Electronic Medical Record-Driven Data Analytics from an Eye Care Network in India.
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Das, Anthony Vipin, Bagga, Bhupesh, and Joseph, Joveeta
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ACANTHAMOEBA keratitis , *EYE care , *ELECTRONIC health records , *RURAL geography , *PENETRATING wounds , *VISUAL acuity - Abstract
To describe the clinical profile of patients presented with Acanthamoeba keratitis (AK) to a multi-tier ophthalmology hospital network in India. This cross-sectional hospital-based study included 1945339 new patients registering between September 2016 and May 2022. Patients with clinically confirmed diagnosis of AK in one or both eyes were included in the study. All the relevant data were documented using an electronic medical record (EMR) system. A total of 245 (0.013%) patients were diagnosed with AK and majority were male (62.86%) with unilateral (99.59%) affliction. The most common age group was during the fourth decade of life, 65 (26.53%) patients and predominantly were adults (95.51%). The prevalence of the infection was higher in patients from a lower socioeconomic status (43.27%) from rural geography (52.24%) and in agriculture-related work (28.16%). The most common inciting factor was injury with vegetative matter (8.98%), dust (7.76%) and contact lens wear (4.49%). The majority of the eyes had blindness (20/400 to 20/1200) in 116 (47.15%) eyes with a presenting visual acuity (logMAR) of 2.14 ± 1.04. Among the surgical interventions, therapeutic keratoplasty was performed in 41 (16.67%) eyes, penetrating keratoplasty in 22 (8.94%) eyes, and evisceration in 2 (0.81%) eyes. AK more commonly affects males presenting during the fourth decade of life from lower socio-economic status and is predominantly unilateral. A fourth of the affected eyes underwent keratoplasty and the majority had significant visual impairment at presentation. [ABSTRACT FROM AUTHOR]
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- 2024
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24. Kronika nr 29.
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Karczewicz, Danuta
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ACANTHAMOEBA keratitis ,BIOORGANIC chemistry ,PUBLISHING ,ORGANIC chemistry ,WIT & humor - Abstract
The text describes the 3rd German-Polish Winter Academy conference held in Rostock, Germany, focusing on ophthalmology. The event featured lectures by prominent scientists from Poland and Germany on eye diseases, oncology, and ophthalmic traumatology. The conference aimed to facilitate knowledge exchange, networking, and discussions on eye health issues, attracting around a hundred ophthalmologists from both countries. Additionally, the text highlights other ophthalmology-related events and achievements, such as the International Conference "From Science to Practice" and the Polish Ophthalmologists Congress in Lublin. [Extracted from the article]
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- 2024
25. Can Acanthamoeba keratitis be properly diagnosed without culture in the real-world clinical microbiology laboratory?: a case report
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Bosung Park, Ho Seok Chung, Eun Jeong Won, Heungsup Sung, and Mi-Na Kim
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acanthamoeba keratitis ,cyst ,trophozoite ,morphology ,Microbiology ,QR1-502 - Abstract
Acanthamoeba species are ubiquitous, free-living organisms found in the environment. They can cause a sight-threatening cornea disease, termed Acanthamoeba keratitis, and are often misdiagnosed, causing delayed administration of the correct treatment. Herein, we report a case of Acanthamoeba keratitis diagnosed without culture. A 12-year-old girl with a history of wearing contact lenses presented with complaints of pain, irritation, and hyperemia in the left eye. Corneal scraping-smeared slide, and liquids with contact lenses were submitted to the clinical microbiology laboratory. Cultures of Acanthamoeba spp. were not available; thus, they were stained with calcofluor white. The isolation of Acanthamoeba from the corneal scraping allowed the detection of trophozoites and cysts based on their morphological characteristics. PCR targeting the 18s rRNA gene and subsequent sequencing revealed 99% identity with the Acanthamoeba spp. Although it is challenging to find real-world evidence of Acanthamoeba in clinical microbiology without using culture methods, this case underscores the need for clinical microbiology laboratories to maintain their inspection capabilities.
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- 2024
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26. Polihexanide (PHMB) Eye Drops in Patients Affected by Acanthamoeba Keratitis
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- 2023
27. Antiamoebic Susceptibility in Acanthamoeba Keratitis: Comparison of Isolates From South India and Northern California.
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Richardson, Quintin, Prajna, Lalitha, Elakkiya, Shanmugam, Kamal, Fathima, Talbott, Maya, Prajna, Namperumalsamy, Rajaraman, Revathi, Cevallos, Vicky, Seitzman, Gerami, Lietman, Thomas, and Keenan, Jeremy
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Humans ,Acanthamoeba Keratitis ,Acanthamoeba ,Chlorhexidine ,Voriconazole ,California - Abstract
PURPOSE: Outcomes of Acanthamoeba keratitis are often worse in India than in the United States. The goal of this study was to determine whether antiamoebic susceptibility patterns were different when comparing Acanthamoeba isolates from India with those of the United States. METHODS: Acanthamoeba isolates were obtained from corneal scrapings of 43 patients with infectious keratitis seen at the Francis I. Proctor Foundation (N = 23) and Aravind Eye Hospital (N = 20) from 2008 through 2012 and plated on growth media. A previously described minimum cysticidal concentration (MCC) assay was performed by a single laboratory technician to assess susceptibility to 5 antiamoebic agents for all isolates. Testing was conducted in triplicate, with the median MCC chosen for analyses. RESULTS: The MCC (μg/mL) of polyhexamethylene biguanide was 6.25 [IQR 5.47-12.5] for Aravind isolates and 6.25 [IQR 6.25-9.375] for Proctor isolates ( P = 0.75), corresponding values were 6.25 [IQR 3.125-6.25] and 3.125 [IQR 3.125-9.375] for chlorhexidine ( P = 0.81), 2500 [IQR 2500-5000] and 5000 [IQR 1250-20,000] for voriconazole ( P = 0.25), 15.6 [IQR 15.6-39.0625] and 15.6 [IQR 15.6-31.25] for hexamidine ( P = 0.92), and 15.6 [IQR 7.81-15.6] and 15.6 [IQR 7.81-31.25] for propamidine ( P = 0.42). CONCLUSIONS: This study found no statistically significant differences in antiamoebic susceptibility of Indian versus US samples from Acanthamoeba keratitis clinical isolates. These findings suggest that differences in antiamoebic susceptibility are likely not responsible for differential outcomes in Acanthamoeba keratitis between the 2 locations.
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- 2023
28. Assessing PCR-Positive Acanthamoeba Keratitis—A Retrospective Chart Review.
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Blaser, Frank, Bajka, Anahita, Grimm, Felix, Metzler, Simone, Herrmann, Didier, Barthelmes, Daniel, Zweifel, Sandrine Anne, and Said, Sadiq
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ACANTHAMOEBA keratitis ,CONSCIOUSNESS raising ,PATIENT education ,CONTACT lenses ,THERAPEUTICS - Abstract
Ophthalmologists' diagnostic and treatment competence in Acanthamoeba keratitis varies widely. This investigator-initiated, retrospective, single-center chart review examined the electronic patient files regarding PCR-positive Acanthamoeba keratitis. We included corneal and contact lens assessments. We further reviewed the patient's medical history, corneal scraping results regarding viral or fungal co-infections, and the duration from symptom onset to final diagnosis. We identified 59 eyes of 52 patients from February 2010 to February 2023, with 31 of 52 (59.6%) being female patients. The median (IQR, range) patient age was 33 (25.3 to 45.5 [13 to 90]) years, and the mean (SD, range) time to diagnosis after symptom onset was 18 (10.5 to 35 [3 to 70]) days. Overall, 7 of 52 (7.7%) patients displayed a bilateral Acanthamoeba infection, and 48 (92.3%) used contact lenses at symptom onset. Regarding other microbiological co-infections, we found virologic PCR testing in 45 of 52 (86.5%) patients, with 3 (6.7%) positive corneal scrapings. Fungal cultures were performed in 49 of 52 (94.2%) patients, with 5 (10.2%) positive corneal scrapings. The medical treatment success rate was 45/46 (97.8%). This study raises awareness of patient education in contact lens handling and screens for further microbial co-infections in suspected Acanthamoeba cases. [ABSTRACT FROM AUTHOR]
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- 2024
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29. Development of an Ex Vivo Porcine Eye Model for Exploring the Pathogenicity of Acanthamoeba.
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Shi, Ming-Der, Sung, Ko-Chiang, Huang, Jian-Ming, Chen, Chun-Hsien, and Wang, Yu-Jen
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ACANTHAMOEBA ,ACANTHAMOEBA keratitis ,SLIT lamp microscopy ,AMOEBA ,IMMUNE system - Abstract
Acanthamoeba, a widely distributed free-living amoeba found in various environments, is an opportunistic pathogen responsible for causing Acanthamoeba keratitis, a condition that may lead to blindness. However, identifying the pathogenicity of Acanthamoeba is challenging due to its complex life cycle, ability to adapt to different environments, variable virulence factors, and intricate interactions with the host immune system. Additionally, the development of an effective model for studying Acanthamoeba pathogenicity is limited, hindering a comprehensive understanding of the mechanisms underlying its virulence and host interactions. The aim of this study was to develop an ex vivo model for Acanthamoeba infection using porcine eyeballs and to evaluate the pathogenicity of the Acanthamoeba isolates. Based on slit lamp and biopsy analysis, the developed ex vivo model is capable of successfully infecting Acanthamoeba within 3 days. Histopathological staining revealed that clinical isolates of Acanthamoeba exhibited greater corneal stroma destruction and invasion in this model than environmental isolates. Our results highlight the importance of an ex vivo porcine eye model in elucidating the pathogenesis of Acanthamoeba infection and its potential implications for understanding and managing Acanthamoeba-related ocular diseases. [ABSTRACT FROM AUTHOR]
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- 2024
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30. Sodium Metabisulfite Inhibits Acanthamoeba Trophozoite Growth through Thiamine Depletion.
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Mooney, Ronnie, Giammarini, Elisa, Corbett, Erin, Thomson, Scott, McKinley, Kevin, Sinisterra Sebastian, Paula, Rodgers, Kiri, O'Donnell, Jana, McGinness, Charles, Roberts, Craig W., Ramaesh, Kanna, and Henriquez, Fiona L.
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ACANTHAMOEBA ,VITAMIN B1 ,ACANTHAMOEBA castellanii ,ACANTHAMOEBA keratitis ,SODIUM ,EYE drops ,THIAMIN pyrophosphate - Abstract
Acanthamoeba keratitis (AK) is a severe infection of the cornea. Prevention and treatment are difficult due to the inefficacy of currently available compounds. The impact of many commonly used compounds for routine examinations of Acanthamoeba is unexplored but might offer insight useful in combatting AK. In this study, we demonstrate that sodium metabisulfite, a common preservation constituent of eye care solutions, was found to be active against Acanthamoeba trophozoites at concentrations lower than that commonly found in eye drops (IC
50 0.03 mg/mL). We demonstrate that sodium metabisulfite depletes thiamine from growth medium and that Acanthamoeba is a thiamine auxotroph, requiring thiamine salvage for growth. The inhibitory effects of sodium metabisulfite can be overcome by thiamine supplementation. These results are consistent with the lack of key enzymes for thiamine biosynthesis in the genome of Acanthamoeba, an area which might prove exploitable using new or existing compounds. Indeed, this study highlights sodium metabisulfite as a useful inhibitor of Acanthamoeba castellanii trophozoites in vitro and that it acts, at least in part, by limiting available thiamine. [ABSTRACT FROM AUTHOR]- Published
- 2024
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31. Inhibitory and anti-adherent effects of Piper betle L. leaf extract against Acanthamoeba triangularis in co-infection with Staphylococcus aureus and Pseudomonas aeruginosa: A sustainable one-health approach.
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Kwankaew, Pattamaporn, Sangkanu, Suthinee, Mitsuwan, Watcharapong, Boonhok, Rachasak, Lao-On, Udom, and Tabo, Hazel L.
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PIPER betle , *PSEUDOMONAS aeruginosa , *ACANTHAMOEBA , *MIXED infections , *ACANTHAMOEBA keratitis , *PATHOGENIC bacteria , *STAPHYLOCOCCUS aureus - Abstract
Background and Aim: Keratitis is a serious ocular infection often caused by pathogenic microorganisms such as Acanthamoeba spp. Among other harmful microbes, Acanthamoeba keratitis presents a particular challenge due to its resistance to conventional antimicrobial agents. Piper betle Linn., commonly known as betel leaf, has been traditionally used for its medicinal properties. This study aimed to assess the potential of the leaf ethanol extract of P. betle Linn. in the treatment of Acanthamoeba triangularis in monoculture and co-culture with two prevalent pathogenic bacteria, Staphylococcus aureus and Pseudomonas aeruginosa, associated with keratitis. Materials and Methods: Minimum inhibitory concentrations (MICs) of A. triangularis, S. aureus, and P. aeruginosa extracts in monoculture and coinfected conditions were examined. In addition, this study explored the potential of the extract in preventing Acanthamoeba adherence in both monoculture and co-culture environments. Scanning electron microscopy (SEM) analysis confirmed the impact of the extract on Acanthamoeba cell membranes, including acanthopodia. Furthermore, a timekill kinetic assay was used to validate the amoebicidal activity of the extract against A. triangularis and the tested bacteria. Results: MICs for trophozoites, cysts, P. aeruginosa, and S. aureus in the monoculture were 0.25, 0.25, 0.51, and 0.128 mg/mL, respectively, whereas the MICs for Acanthamoeba coinfected with bacteria were higher than those in the monoculture. This extract inhibited the growth of A. triangularis trophozoites and cysts for up to 72 h. Moreover, P. betle extract effectively prevented the adherence of Acanthamoeba to contact lenses under monoculture conditions. SEM analysis confirmed that P. betle extract affects the cell membrane of Acanthamoeba, including Acanthopodia. In addition, the time-kill kinetic assay confirmed that the extract contained amoebicidal activity against A. triangularis, including the tested bacteria. Notably, S. aureus was more susceptible than A. triangularis and P. aeruginosa to P. betle extract treatment. Unexpectedly, our study revealed that S. aureus negatively affected A. triangularis in the co-culture after 3 days of incubation, whereas P. aeruginosa facilitated the growth of A. triangularis in the presence of the extract. Conclusion: This study provides compelling evidence of the anti-adhesive and anti-Acanthamoeba properties of P. betle leaf extract against A. triangularis under monoculture and co-culture conditions. The observed impact on Acanthamoeba cell membranes, coupled with the time-kill kinetic assay results, underscores the potential of P. betle leaf extract as a promising agent for combating Acanthamoeba-related infections in humans and animals. [ABSTRACT FROM AUTHOR]
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- 2024
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32. Acanthamoeba keratitis -- A review.
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Raghavan, Anita and Rammohan, Ram
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ACANTHAMOEBA keratitis , *EARLY diagnosis , *MIXED infections , *DIAGNOSIS , *PATHOLOGICAL physiology - Abstract
This is a comprehensive review after a thorough literature search in PubMed-indexed journals, incorporating current information on the pathophysiology, clinical features, diagnosis, medical and surgical therapy, as well as outcomes of Acanthamoeba keratitis (AK). AK is a significant cause of ocular morbidity, and early diagnosis with timely institution of appropriate therapy is the key to obtaining good outcomes. The varied presentations result in frequent misdiagnosis, and co-infections can increase the morbidity of the disease. The first line of therapy continues to be biguanides and diamidines, with surgery as a last resort. [ABSTRACT FROM AUTHOR]
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- 2024
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33. Understanding Acanthamoeba Keratitis: An In-Depth Review of a Sight-Threatening Eye Infection.
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Petrillo, Francesco, Tortori, Antonia, Vallino, Veronica, Galdiero, Marilena, Fea, Antonio M., De Sanctis, Ugo, and Reibaldi, Michele
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ACANTHAMOEBA keratitis ,EYE infections ,DELAYED diagnosis ,SYMPTOMS ,VISION disorders - Abstract
Acanthamoeba keratitis (AK) is a rare but potentially sight-threatening corneal infection caused by the Acanthamoeba parasite. This microorganism is found ubiquitously in the environment, often in freshwater, soil, and other sources of moisture. Despite its low incidence, AK presents significant challenges due to delayed diagnosis and the complex nature of therapeutic management. Early recognition is crucial to prevent severe ocular complications, including corneal ulceration and vision loss. Diagnostic modalities and treatment strategies may vary greatly depending on the clinical manifestation and the available tools. With the growing reported cases of Acanthamoeba keratitis, it is essential for the ophthalmic community to thoroughly understand this condition for its effective management and improved outcomes. This review provides a comprehensive overview of AK, encompassing its epidemiology, risk factors, pathophysiology, clinical manifestations, diagnosis, and treatment. [ABSTRACT FROM AUTHOR]
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- 2024
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34. Efficacy of propolis extract and eye drop solutions to suppress encystation and excystation of Acanthamoeba triangularis WU19001-T4 genotype.
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Suthinee Sangkanu, Abolghasem Siyadatpanah, Roghayeh Norouzi, Julalak Chuprom, Watcharapong Mitsuwan, Sirirat Surinkaew, Rachasak Boonhok, Paul, Alok K., Tooba Mahboob, Imran Sama-ae, Oliveira, Sonia M. R., Jimoh, Tajudeen O., Pereira, Maria de Lourdes, Polrat Wilairatana, Wiart, Christophe, Mohammed Rahmatullah, Monvaris Sakolnapa, and Veeranoot Nissapatorn
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PROPOLIS ,EYE drops ,ACANTHAMOEBA ,ACANTHAMOEBA keratitis ,NATURAL products ,CULTIVARS - Abstract
Background: Propolis is a natural resinous product from a variety of plants and combines it with beeswax and salivary enzymes to create bee glue. Its potentials have been employed in the treatment of many diseases and conditions for centuries. This study, therefore, aims to determine the anti-Acanthamoeba properties of the propolis extract, eye drops coupled to some mechanisms such as inhibition of encystation and excystation. Methods: The minimum inhibitory concentrations (MICs) of the most active propolis extract were assessed in trophozoites and cysts of Acanthamoeba triangularis (A. triangularis) at 0.256 and 1 mg/mL, respectively. Results: Active eye drops inhibited trophozoites and cysts with a MIC value of 100%. At concentrations lower than their MICs values (1/2--1/16 MIC), propolis and eye drops revealed inhibition of encystation. In addition, at 1/2 MIC, both the propolis extract and eye drops showed potential inhibition of excystation. In combined sets of propolis extract and eye drops, they showed slightly increasing inhibition of encystation and excystation. Surprisingly, the MIC of chlorhexidine decreased when combined with the propolis and eye drops. SEM and TEM images displayed morphological changes in A. triangularis treated with combined sets of propolis extract and eye drops. Conclusion: From this study, a new combined eye drop solution with propolis extract was found to be helpful in reducing encystation and excystation in A. triangularis. Therefore, this combination is an alternative for the treatment of eye diseases in early stages along with reducing the entry into the cyst stage of Acanthamoeba. The results of this study revealed new anti-Acanthamoeba inhibitors with promising combined alternative therapeutic potential for the treatment of Acanthamoeba keratitis. [ABSTRACT FROM AUTHOR]
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- 2024
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35. Autophagic cell death induction in a clinical isolate of Acanthamoeba sp. treated with methanolic extracts of Pereskia bleo Kuhn.
- Author
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Razali, Razifah Mohd, Abdullah, Fatin Amira, Mohd Basri, Nur Nabilah, Tajudin Tuan Johari, Syed Ahmad, Manisekaran, Thivyan, and Hashim, Fatimah
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PERESKIA ,CELL death ,ACANTHAMOEBA ,METHANOL ,ANTIOXIDANTS - Abstract
Aims: This study was aimed to investigate the effects of methanol extracts from various parts of the Pereskia bleo Kuhn plant on Acanthamoeba sp. The antioxidant levels of each extract from different plant parts were measured after the extraction process. These extracts were then exposed to Acanthamoeba sp. to assess dose-response, IC
50 values, changes in cell morphology, internal cell activity and apoptosis based on alterations in phospholipids. Methodology and results: The total phenolic content, carotenoid estimation and antioxidant activity of the leaves, flowers and fruits of P. bleo were measured based on 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH) assay. Its antiamoebic properties were tested using 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay for the IC50 determination. The morphological and biochemical changes in the Acanthamoeba sp. were observed under light and fluorescence microscopy using the acridine orange and propidium iodide double staining (AO/PI). The IC50 values of P. bleo leaves, flowers and fruits methanolic extracts were 5.884%, 0.1646% and 20.69%, respectively. Morphological observation displayed shortened acanthapodia with darkened cytoplasms. AO/PI-stained Acanthamoeba sp. cells appear with orange-fluorescent organelles in their green cytoplasm, indicating autophagic cell deaths. Apoptotic and necrotic Acanthamoeba sp. cells were absent based on Annexin V labelling. Conclusion, significance and impact of study: This study confirmed that the methanolic crude extracts of P. bleo exhibit high cytotoxic potential towards Acanthamoeba sp. trophozoites by inducing an autophagic mode of cell death. [ABSTRACT FROM AUTHOR]- Published
- 2024
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36. Comparison of therapeutic effects between big-bubble deep anterior lamellar keratoplasty and penetrating keratoplasty for medically unresponsive Acanthamoeba keratitis
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Xiaolin Qi, Huilin Mao, Jinhui Liu, Yanling Dong, Man Du, Ting Liu, Ting Zhang, Xiuhai Lu, and Hua Gao
- Subjects
Acanthamoeba keratitis ,Big-bubble deep anterior lamellar keratoplasty ,Penetrating keratoplasty ,Postoperative recurrence ,Immune rejection ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Purpose To compare the outcomes of big-bubble deep anterior lamellar keratoplasty (BB-DALK) and penetrating keratoplasty (PKP) in the management of medically unresponsive Acanthamoeba keratitis (AK). Methods This retrospective study included 27 eyes of BB-DALK and 24 eyes of PKP from a tertiary ophthalmology care centre. Glucocorticoid eye drops were subsequently added to the treatment plan 2 months postoperatively based on the evaluation using confocal laser scanning microscopy. The clinical presentations, best-corrected visual acuity (BCVA), postoperative refractive outcomes, graft survival, and Acanthamoeba recurrence were analyzed. Results The AK patients included in the study were in stage 2 or stage 3, and the percentage of patients in stage 3 was higher in the PKP group (P = 0.003). Clinical presentations were mainly corneal ulcers and ring infiltrates, and endothelial plaques, hypopyon, uveitis and glaucoma were more common in the PKP group (P = 0.007). The BCVA and the graft survival rate showed no statistically significant differences between the two groups at 1 year after surgery. However, 3 years postoperatively, the BCVA of 0.71 ± 0.64 logMAR, the graft survival rate of 89.5%, and the endothelial cell density of 1899 ± 125 cells per square millimeter in the BB-DALK group were significantly better than those of the PKP group (P = 0.010, 0.046, and 0.032, respectively). 3 eyes (11.1%) in the BB-DALK group and 2 eyes (8.3%) in the PKP group experienced Acanthamoeba recurrence, but the rates showed no statistically significant difference between the two groups (P = 1.000). In the PKP group, immune rejection and elevated intraocular pressure were observed in 5 and 6 eyes, respectively. Conclusion Corneal transplantation is recommended for AK patients unresponsive to antiamoebic agents. The visual acuity and graft survival can be maintained after BB-DALK surgery. Acanthamoeba recurrence is not related to the surgical approach performed, whereas complete dissection of the infected corneal stroma and delayed prescribing of glucocorticoid eye drops were important to prevent recurrence.
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- 2024
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37. Comparison of therapeutic effects between big-bubble deep anterior lamellar keratoplasty and penetrating keratoplasty for medically unresponsive Acanthamoeba keratitis
- Author
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Qi, Xiaolin, Mao, Huilin, Liu, Jinhui, Dong, Yanling, Du, Man, Liu, Ting, Zhang, Ting, Lu, Xiuhai, and Gao, Hua
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- 2024
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38. Chitosan nanoparticles improve the effectivity of miltefosine against Acanthamoeba.
- Author
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Latifi, Alireza, Esmaeili, Fariba, Mohebali, Mehdi, Yasami-Khiabani, Setayesh, Rezaeian, Mostafa, Soleimani, Mohammad, Kazemirad, Elham, and Amani, Amir
- Subjects
- *
MILTEFOSINE , *CHITOSAN , *ACANTHAMOEBA , *ACANTHAMOEBA keratitis , *NANOPARTICLES - Abstract
Background: Acanthamoeba keratitis (AK) is a corneal sight-threatening infection caused by the free-living amoebae of the genus Acanthamoeba. Early and appropriate treatment significantly impacts visual outcomes. Mucoadhesive polymers such as chitosan are a potential strategy to prolong the residence time and bioavailability of the encapsulated drugs in the cornea. Regarding the recent administration of miltefosine (MF) for treating resistant AK, in the present study, we synthesized miltefosine-loaded chitosan nanoparticles (MF-CS-NPs) and evaluated them against Acanthamoeba. Methodology/Principal findings: Chitosan nanoparticles (CNPs) were prepared using the ionic gelation method with negatively charged tripolyphosphate (TPP). The zeta-potential (ZP) and the particle size of MF-CS-NPs were 21.8±3.2 mV and 46.61±18.16 nm, respectively. The release profile of MF-CS-NPs indicated linearity with sustained drug release. The cytotoxicity of MF-CS-NPs on the Vero cell line was 2.67 and 1.64 times lower than free MF at 24 and 48 hours. This formulation exhibited no hemolytic activity in vitro and ocular irritation in rabbit eyes. The IC50 of MF-CS-NPs showed a significant reduction by 2.06 and 1.69-fold in trophozoites at 24 and 48 hours compared to free MF. Also, the MF-CS-NPs IC50 in the cysts form was slightly decreased by 1.26 and 1.21-fold at 24 and 48 hours compared to free MF. Conclusions: The MF-CS-NPs were more effective against the trophozoites and cysts than free MF. The nano-chitosan formulation was more effective on trophozoites than the cysts form. MF-CS-NPs reduced toxicity and improved the amoebicidal effect of MF. Nano-chitosan could be an ideal carrier that decreases the cytotoxicity of miltefosine. Further analysis in animal settings is needed to evaluate this nano-formulation for clinical ocular drug delivery. Author summary: Acanthamoeba keratitis (AK) is a painful corneal disease that causes vision loss if not treated promptly. AK incidence is increasing worldwide, especially among those who wear contact lenses. Prompt and proper treatment is essential for complete recovery of vision. The successful treatment has been complicated due to low efficacy, toxicity, and ineffectual ocular drug delivery. Mucoadhesive polymers, like chitosan nanoparticles, are a promising approach to enhancing drug residence time and transcorneal permeation. Miltefosine (MF) is an effective medication for treating refractory AK. In the present study, miltefosine-loaded chitosan nanoparticles were prepared, and their therapeutic effect and cytotoxicity were compared with free miltefosine. The MF-CS-NPs demonstrated a significant decrease in the viability of trophozoite forms compared to free miltefosine. The nano-chitosan formulation was more effective toward trophozoites than the cysts form. Overall, the chitosan nanoparticles improved the effectiveness of miltefosine against Acanthamoeba. Besides, this formulation notably reduced toxicity compared to free MF, exhibiting no in-vivo irritation. The nano-chitosan carrier can be proposed as an ideal nanocarrier for future evaluation in AK treatment. [ABSTRACT FROM AUTHOR]
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- 2024
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39. Differentiation of acanthamoeba keratitis from other non-acanthamoeba keratitis: Risk factors and clinical features.
- Author
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Alreshidi, Shaker Osaywid, Vargas, José Manuel, Ahmad, Khabir, Alothman, Ahmed Yousef, Albalawi, Eman D., Almulhim, Abdulmohsen, Alenezi, Saad Hamdan, ALBalawi, Hani Basher, Alali, Naif Mamdouh, Hashem, Faris, and Aljindan, Mohanna
- Subjects
- *
ACANTHAMOEBA keratitis , *KERATITIS , *FUNGAL keratitis , *PATIENTS , *OPHTHALMOLOGIC emergencies - Abstract
Introduction: Infectious Keratitis is one of the most common ocular emergencies seen by ophthalmologists. Our aim is to identify the risk factors and clinical features of Acanthamoeba Keratitis (AK). Methods: This retrospective chart review study was conducted at King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia, and included all the microbial keratitis cases, male and female patients of all ages. The main outcome is the differentiation between various microbial keratitis types. Results: We included 134 consecutive eyes of 126 persons. We had 24 cases of acanthamoeba keratitis, 22 bacterial keratitis, 24 fungal keratitis, 32 herpetic keratitis, and 32 bacterial co-infection. Contact lens wear was found in 33 eyes (24.6%). Among acanthamoeba keratitis patients, 73% were ≤ 39 years of age, and 73% were females (P <0.001). Also, in AK cases, epithelial defect was found in all cases (100%), endothelial plaques were found in 18 eyes (69.2%), 12 cases had radial keratoneuritis (46.2%), and ring infiltrate was found in 53.8% of AK cases. Conclusions: We determined the factors that increase the risk of acanthamoeba infection and the clinical characteristics that help distinguish it from other types of microbial keratitis. Our findings suggest that younger females and patients who wear contact lenses are more likely to develop acanthamoeba keratitis. The occurrence of epitheliopathy, ring infiltrate, radial keratoneuritis, and endothelial plaques indicate the possibility of acanthamoeba infection. Promoting education on wearing contact lenses is essential to reduce the risk of acanthamoeba infection, as it is the most significant risk factor for this infection. [ABSTRACT FROM AUTHOR]
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- 2024
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40. Could giant viruses be considered as a biotechnological tool for preventing and controlling Acanthamoeba infections?
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Crispim, Ana Paula Correia, Serafim, Mateus Sá Magalhães, Costa, Adriana Oliveira, and Abrahão, Jônatas Santos
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ACANTHAMOEBA keratitis , *ACANTHAMOEBA castellanii , *CONTACT lenses , *INFECTION control , *CYTOTOXINS - Abstract
Aim The aim of the study was to evaluate the efficiency of mimivirus as a potential therapeutic and prophylactic tool against Acanthamoeba castellanii , the etiological agent of Acanthamoeba keratitis, a progressive corneal infection, that is commonly associated with the use of contact lenses and can lead to blindness if not properly treated. Methods and results Mimivirus particles were tested in different multiplicity of infection, along with commercial multipurpose contact lenses' solutions, aiming to assess their ability to prevent encystment and excystment of A. castellanii. Solutions were evaluated for their amoebicidal potential and cytotoxicity in MDCK cells, as well as their effectiveness in preventing A. castellanii damage in Madin-Darby canine kidney (MDCK) cells. Results indicated that mimivirus was able to inhibit the formation of A. castellanii cysts, even in the presence of Neff encystment solution. Mimivirus also showed greater effectiveness in controlling A. castellanii excystment compared to commercial solutions. Additionally, mimivirus solution was more effective in preventing damage caused by A. castellanii , presented greater amoebicidal activity, and were less cytotoxic to MDCK cells than commercial MPS. Conclusions Mimivirus demonstrates a greater ability to inhibit A. castellanii encystment and excystment compared to commercial multipurpose contact lens solutions. Additionally, mimivirus is less toxic to MDCK cells than those commercial solutions. New studies utilizing in vivo models will be crucial for confirming safety and efficacy parameters. [ABSTRACT FROM AUTHOR]
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- 2024
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41. Molecular detection and characterization of Acanthamoeba infection in dogs and its association with keratitis in Korea.
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Subin Lee, Badriah Alkathiri, Ji Seung Jung, Nanyoung Kang, Jiyi Hwang, Sang-Eun Park, Yeonchul Hong, Kyung-Mee Park, and Seung-Hun Lee
- Abstract
Acanthamoeba infection is associated with keratitis in humans; however, its association with keratitis in dogs remains unclear. To investigate this possibility, we collected 171 conjunctival swab samples from dogs with eye-related diseases (65 with keratitis and 106 without keratitis) at Chungbuk National University Veterinary Teaching Hospital, Korea, from August 2021 to September 2022. Polymerase chain reaction identified 9 samples (5.3%) as Acanthamoeba positive; of these, 3 were from dogs with keratitis (4.6%) and 6 were from dogs without keratitis (5.7%). Our results indicated no significant association between Acanthamoeba infection and keratitis, season, sex, or age. All Acanthamoeba organisms found in this study had the genotype T4, according to 18S ribosomal RNA analysis. Acanthamoeba infection in dogs might have only a limited association with keratitis. [ABSTRACT FROM AUTHOR]
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- 2024
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42. Epidemiology of and Genetic Factors Associated with Acanthamoeba Keratitis.
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Ilyas, Muhammad, Stapleton, Fiona, Willcox, Mark D. P., Henriquez, Fiona, Peguda, Hari Kumar, Rayamajhee, Binod, Zahid, Tasbiha, Petsoglou, Constantinos, and Carnt, Nicole A.
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ACANTHAMOEBA keratitis ,GENETIC epidemiology ,PROTOZOAN diseases ,CONTACT lenses ,OCULAR injuries - Abstract
Acanthamoeba keratitis (AK) is a severe, rare protozoal infection of the cornea. Acanthamoeba can survive in diverse habitats and at extreme temperatures. AK is mostly seen in contact lens wearers whose lenses have become contaminated or who have a history of water exposure, and in those without contact lens wear who have experienced recent eye trauma involving contaminated soil or water. Infection usually results in severe eye pain, photophobia, inflammation, and corneal epithelial defects. The pathophysiology of this infection is multifactorial, including the production of cytotoxic proteases by Acanthamoeba that degrades the corneal epithelial basement membrane and induces the death of ocular surface cells, resulting in degradation of the collagen-rich corneal stroma. AK can be prevented by avoiding risk factors, which includes avoiding water contact, such as swimming or showering in contact lenses, and wearing protective goggles when working on the land. AK is mostly treated with an antimicrobial therapy of biguanides alone or in combination with diaminidines, although the commercial availability of these medicines is variable. Other than anti-amoeba therapies, targeting host immune pathways in Acanthamoeba disease may lead to the development of vaccines or antibody therapeutics which could transform the management of AK. [ABSTRACT FROM AUTHOR]
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- 2024
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- View/download PDF
43. The role of naturally acquired intracellular Pseudomonas aeruginosa in the development of Acanthamoeba keratitis in an animal model.
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Rayamajhee, Binod, Willcox, Mark, Henriquez, Fiona L., Vijay, Ajay Kumar, Petsoglou, Constantinos, Shrestha, Gauri, Peguda, Hari Kumar, and Carnt, Nicole
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ACANTHAMOEBA keratitis , *PSEUDOMONAS aeruginosa , *ANAPLASMA phagocytophilum , *FLUORESCENCE in situ hybridization , *PSEUDOMONADACEAE , *ANIMAL models in research , *ACANTHAMOEBA , *Q fever - Abstract
Background: Acanthamoeba is an environmental host for various microorganisms. Acanthamoeba is also becoming an increasingly important pathogen as a cause of keratitis. In Acanthamoeba keratitis (AK), coinfections involving pathogenic bacteria have been reported, potentially attributed to the carriage of microbes by Acanthamoeba. This study assessed the presence of intracellular bacteria in Acanthamoeba species recovered from domestic tap water and corneas of two different AK patients and examined the impact of naturally occurring intracellular bacteria within Acanthamoeba on the severity of corneal infections in rats. Methodology/Principal findings: Household water and corneal swabs were collected from AK patients. Acanthamoeba strains and genotypes were confirmed by sequencing. Acanthamoeba isolates were assessed for the presence of intracellular bacteria using sequencing, fluorescence in situ hybridization (FISH), and electron microscopy. The viability of the bacteria in Acanthamoeba was assessed by labelling with alkyne–functionalized D–alanine (alkDala). Primary human macrophages were used to compare the intracellular survival and replication of the endosymbiotic Pseudomonas aeruginosa and a wild type strain. Eyes of rats were challenged intrastromally with Acanthamoeba containing or devoid of P. aeruginosa and evaluated for the clinical response. Domestic water and corneal swabs were positive for Acanthamoeba. Both strains belonged to genotype T4F. One of the Acanthamoeba isolates harboured P. aeruginosa which was seen throughout the Acanthamoeba's cytoplasm. It was metabolically active and could be seen undergoing binary fission. This motile strain was able to replicate in macrophage to a greater degree than strain PAO1 (p<0.05). Inoculation of Acanthamoeba containing the intracellular P. aeruginosa in rats eyes resulted in a severe keratitis with increased neutrophil response. Acanthamoeba alone induced milder keratitis. Conclusions/Significance: Our findings indicate the presence of live intracellular bacteria in Acanthamoeba can increase the severity of acute keratitis in vivo. As P. aeruginosa is a common cause of keratitis, this may indicate the potential for these intracellular bacteria in Acanthamoeba to lead to severe polymicrobial keratitis. Author summary: In recent years, Acanthamoeba spp. have become an increasingly important human pathogen, causing serious, debilitating, and sometimes deadly infections. It can cause a rare but severe and potentially blinding corneal infection known as Acanthamoeba keratitis, which is extremely painful, difficult to diagnose, and treat. In a remarkable dual role, Acanthamoeba species act as phagocytic predator, consuming other microbes, but also as environmental hosts for a wide range of bacteria. With the increasing prevalence of coinfections among AK patients, which often lead to the severe outcomes, it is important to identify the intracellular bacteria hosted by Acanthamoeba spp. Using a series of experiments we confirmed the presence of intracellular P. aeruginosa in an Acanthamoeba strain isolated from AK patient domestic tap water. Our study findings showed that amoeba adapted P. aeruginosa exhibited enhanced intracellular survival and replication in human monocyte derived macrophages (hMDMs) compared to the wild–type strain PAO1. Here, for the first time, we investigated the role of naturally acquired viable intracellular P. aeruginosa in the development of Acanthamoeba keratitis in rats. The presence of intracellular bacteria in Acanthamoeba resulted into acute keratitis, highlighting the importance of identifying endosymbionts harbored by Acanthamoeba for accurate differential diagnostics and prognostic evaluations of Acanthamoeba keratitis. [ABSTRACT FROM AUTHOR]
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- 2024
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44. Diagnosing and monitoring the characteristics of Acanthamoeba keratitis using slit scanning and laser scanning in vivo confocal microscopy.
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Curro‐Tafili, K., Verbraak, F. D., de Vries, R., van Nispen, R. M. A., and Ghyczy, E. A. E.
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Introduction: Acanthamoeba keratitis (AK) is a serious and potentially blinding ocular infection caused by the free‐living amoeba, Acanthamoeba. In vivo confocal microscopy (IVCM) is a non‐invasive device which has been proven of great use to diagnose Acanthamoeba infections immediately. The aim of this review was to establish different patterns and signs of AK that appear on the IVCM both before and after treatment. Methods: A systematic review of the literature from 1974 until September 2021 was performed using Embase and PubMed, following The Preferred Reporting Items for Systematic reviews and Meta‐Analyses (PRISMA) guidelines. Results: Twenty different signs of AK were observed using IVCM. The included studies used vastly different criteria to diagnose infections, ranging from just 1 to 13 of the signs, demonstrating the current lack of a standardised diagnosis of this infection using the IVCM. The appearance of double wall cysts, trophozoites, signet rings, target signs and clusters were shown to be pathognomonic to AK infections. Bright spots located in the corneal epithelium were demonstrated as non‐reliable predictors of AK. The presence of cysts in clusters and single file can predict the need for corneal transplantation. The morphological changes in cysts using the IVCM following treatment were described as breaking down to hollow forms and occasionally surrounded by black cavities. Using this information, a visual guideline for identifying AK signs in diagnosis and follow‐up using IVCM was created. Conclusion: Increased awareness of the different signs and patterns of AK that appear on the IVCM is crucial in order to correctly identify an infection and increase the potential of this device. Our guidelines presented here can be used, but further studies are needed in order to determine the relationship and aetiology of these signs and cellular changes on the IVCM both before and after anti‐amoeba treatment. [ABSTRACT FROM AUTHOR]
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- 2024
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45. Depth, size of infiltrate, and the microbe – The trio that prognosticates the outcome of infective keratitis.
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Agarwal, Shweta, Srinivasan, Bhaskar, Iyer, Geetha, Pandey, Sunita, Agarwal, Manokamna, Dhiman, Richa, Surya, Janani, and Anand, Appakkudal
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KERATITIS , *ACANTHAMOEBA keratitis , *FUNGAL keratitis , *EYE care , *VISUAL acuity - Abstract
Purpose: To analyze the influence of infiltrate size, depth, and organism on the outcome of microbial keratitis. Design: Retrospective comparative study. Methods: Medical records of patients with infective keratitis, who reported from January 2015 to December 2019 to a tertiary eye care center, were analyzed. Size and depth of ulcer at presentation were the factors used to group patients, and the influence on the outcome of the organism causing it was analyzed. Grouping was as follows: group A: ulcer size <6 mm/anterior to midstromal infiltrate, group B: ulcer < 6 mm/full-thickness infiltrate, group C: ulcer >6 mm/anterior to midstromal infiltrate, group D: ulcer > 6 mm/full-thickness infiltrate. Patients with viral keratitis or unidentified organism were excluded. Response to treatment and best-corrected visual acuity (BCVA) at the final follow-up were the outcome measures. Results: In the study, 1117/6276 patients were included, with 60.8% patients in group A. A significant improvement in visual acuity was noted in groups A/B compared to groups C/D. Group A had the best response to medical management, irrespective of the organism. Higher risk for surgery was noted in group C compared to group B, with group A as the reference. Overall resolution with medical treatment was noted in 70% miscellaneous keratitis, 64.8% bacterial keratitis, 64.3% mixed keratitis, 62.5% acanthamoeba keratitis, 52.6% fungal keratitis, and 12.1% Pythium keratitis. Bacteria and acanthamoeba responded better to medical management than fungal keratitis, whereas Pythium had the highest risk for surgery. Conclusion: An interplay between virulence of the organism along with depth and size of the infiltrate determines the outcome of microbial keratitis. [ABSTRACT FROM AUTHOR]
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- 2024
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- View/download PDF
46. Quantitative evaluation of corneal irregularity and scarring after infectious keratitis using anterior segment optical coherence tomography.
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Ichikawa, Kazunori, Ono, Takashi, Chen, Lily, Kitamoto, Kohdai, Taketatni, Yukako, Toyono, Tetsuya, Yoshida, Junko, Aihara, Makoto, and Miyai, Takashi
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- *
ANTERIOR eye segment , *OPTICAL coherence tomography , *ASTIGMATISM (Optics) , *CORNEA , *VISION , *KERATITIS , *ACANTHAMOEBA keratitis - Abstract
Purpose: Corneal scars after infectious keratitis lead to insufficient transparency and irregular astigmatism, affecting visual acuity; therefore, they should be accurately evaluated to estimate visual function. This study aimed to quantitatively evaluate corneal irregularity and scarring after infectious keratitis using anterior segment optical coherence tomography (AS-OCT). Methods: This was an observational clinical study. We included patients who had corneal scarring after treatment of infectious keratitis between 2014 and 2021 at University of Tokyo Hospital. We retrospectively examined best spectacle-corrected visual acuity (BSCVA), average keratometric power, central corneal thickness (CCT), and four components of the Fourier harmonic analysis including spherical and asymmetry components, as well as regular astigmatism and higher-order irregularity. We included anterior and posterior corneal data and compared results with those of contralateral healthy eyes. Additionally, we quantitatively evaluated the densitometry of the cornea obtained using AS-OCT. Results: A total of 122 eyes of 61 patients were examined; male predominance was observed (n = 37), and the mean patient age was 55.3 ± 19.4 years. Comparisons with contralateral healthy eyes showed that BSCVA worsened (0.30 ± 0.83 and 0.93 ± 1.36 logMAR, respectively, P = 0.003), and CCT (531.1 ± 46.2 and 591.8 ± 132.4 μm, respectively, P < 0.001) and corneal densitometry (84.4 ± 11.8 and 111.9 ± 19.2 grayscale units, respectively, P < 0.001) increased significantly in affected eyes. The asymmetry component and higher-order irregularities that were not corrected with spectacles significantly increased (both P < 0.001), and there were no significant differences in the changes among the bacterial, fungal, herpetic, and acanthamoeba types of keratitis. Conclusion: Corneal scarring persisted after treatment for infectious keratitis, and the asymmetry and irregularities of corneal astigmatism increased as visual acuity deteriorated. AS-OCT with the Fourier harmonic analysis was useful for evaluating corneal topographic changes in patients with corneal scarring after keratitis. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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47. Acanthamoeba Keratitis, a Case Report.
- Author
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Moore, Lee and Staehling, Megan
- Subjects
ACANTHAMOEBA keratitis ,PROTOZOAN diseases ,EYE infections ,POLYMERASE chain reaction - Abstract
Acanthamoeba keratitis (AK) is a rare but devastating protozoal eye infection that is challenging to diagnose and resistant to treatment. This report describes the first known case of AK in Mississippi to be confirmed by laboratory testing. A newly available proprietary polymerase reaction chain (PCR) assay (HealthTrackRx, Denton, Texas) identified the fastidious pathogen which would have otherwise been undetected using readily available traditional culture media alone. [ABSTRACT FROM AUTHOR]
- Published
- 2024
48. Development of a Machine Learning-Based Cysticidal Assay and Identification of an Amebicidal and Cysticidal Marine Microbial Metabolite against Acanthamoeba
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Shing, Brian, Balen, Mina, Fenical, William, and Debnath, Anjan
- Subjects
Infectious Diseases ,Acanthamoeba Keratitis ,Acanthamoeba castellanii ,Amebicides ,Animals ,Machine Learning ,Trophozoites ,Acanthamoeba ,amoeba ,assay development ,cysticidal ,cysts ,drug discovery ,free-living amoeba ,machine learning ,natural antimicrobial products ,trophozoites - Abstract
Traditional cysticidal assays for Acanthamoeba species revolve around treating cysts with compounds and manually observing the culture for evidence of excystation. This method is time-consuming, labor-intensive, and low throughput. We adapted and trained a YOLOv3 machine learning, object detection neural network to recognize Acanthamoeba castellanii trophozoites and cysts in microscopy images to develop an automated cysticidal assay. This trained neural network was used to count trophozoites in wells treated with compounds of interest to determine if a compound treatment was cysticidal. We validated this new assay with known cysticidal and noncysticidal compounds. In addition, we undertook a large-scale bioluminescence-based screen of 9,286 structurally unique marine microbial metabolite fractions against the trophozoites of A. castellanii and identified 29 trophocidal hits. These hits were then subjected to this machine learning-based automated cysticidal assay. One marine microbial metabolite fraction was identified as both trophocidal and cysticidal. IMPORTANCE The free-living Acanthamoeba can exist as a trophozoite or cyst and both stages can cause painful blinding keratitis. Infection recurrence occurs in approximately 10% of cases due to the lack of efficient drugs that can kill both trophozoites and cysts. Therefore, the discovery of therapeutics that are effective against both stages is a critical unmet need to avert blindness. Current efforts to identify new anti-Acanthamoeba compounds rely primarily upon assays that target the trophozoite stage of the parasite. We adapted and trained a machine learning, object detection neural network to recognize Acanthamoeba trophozoites and cysts in microscopy images. Our machine learning-based cysticidal assay improved throughput, demonstrated high specificity, and had an exquisite ability to identify noncysticidal compounds. We combined this cysticidal assay with our bioluminescence-based trophocidal assay to screen about 9,000 structurally unique marine microbial metabolites against A. castellanii. Our screen identified a marine metabolite that was both trophocidal and cysticidal.
- Published
- 2022
49. Use of Amniotic Membrane Transplant and Deep Anterior Keratoplasty in a Patient with Bilateral Acanthamoeba Infectious Keratitis: A Case Report
- Author
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Carlos A. Müller-Morales, Guillermo Raul Vera-Duarte, Valeria Oliva-Bienzobas, Arturo Ramirez-Miranda, Alejandro Navas, and Enrique O. Graue-Hernandez
- Subjects
acanthamoeba keratitis ,amniotic membrane transplant ,deep anterior keratoplasty ,Ophthalmology ,RE1-994 - Abstract
The aim of this study was to report a case with the use of amniotic membrane transplant and deep anterior keratoplasty in a patient with bilateral Acanthamoeba infectious keratitis as a treatment. A 20-year-old male presented with bilateral Acanthamoeba keratitis (AK) who was initially diagnosed with herpetic keratitis receiving full antiviral and corticosteroid topical treatment without any improvement. Corneal biopsy was performed to confirm the suspected diagnosis, and Acanthamoeba stromal cysts were identified in the sample. Treatment was initiated with 0.02% chlorhexidine, 0.1% propamidine isethionate, neomycin, and tropicamide/phenylephrine. Symptoms and clinical improvement were achieved between the 8th and 10th weeks, so corticosteroids were initiated. Treatment was continued until we observed a poor response in the left eye; therefore, an epithelial scraping and amniotic membrane placement were performed. Lately, the right eye underwent a deep anterior lamellar keratoplasty. A challenging case of bilateral AK managed with topical medications, amniotic membrane, and corneal keratoplasty. The earlier the disease is diagnosed, the better the outcome. If the diagnosis is delayed, the amoebas have penetrated deep into the corneal stroma, and successful therapy becomes difficult. A surgical option can be an early solution with a good prognosis for these cases.
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- 2023
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50. Outcomes of amoebic, fungal, and bacterial keratitis: A retrospective cohort study
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Moe, Caitlin A, Lalitha, Prajna, Prajna, N Venkatesh, Mascarenhas, Jeena, Srinivasan, Muthiah, Das, Manoranhan, Panigrahi, Arun, Rajaraman, Revathi, Seitzman, Gerami D, Oldenburg, Catherine E, Lietman, Thomas M, and Keenan, Jeremy D
- Subjects
Emerging Infectious Diseases ,Clinical Research ,Eye Disease and Disorders of Vision ,Clinical Trials and Supportive Activities ,Infectious Diseases ,Evaluation of treatments and therapeutic interventions ,6.1 Pharmaceuticals ,Infection ,Acanthamoeba ,Acanthamoeba Keratitis ,Adult ,Anti-Infective Agents ,Bacteria ,Eye Infections ,Bacterial ,Eye Infections ,Fungal ,Female ,Fungi ,Humans ,Male ,Middle Aged ,Prognosis ,Re-Epithelialization ,Retrospective Studies ,Risk Factors ,General Science & Technology - Abstract
BackgroundAcanthamoeba keratitis is challenging to treat and thought to result in poor outcomes, but very few comparative studies exist to assess whether ulcers caused by Acanthamoeba are worse than those caused by bacteria or fungus.MethodsIn a retrospective cohort study, all cases of smear- or culture-proven Acanthamoeba keratitis diagnosed from January 2006 to June 2011 at an eye hospital in South India were identified from the microbiology database. Random samples of the same number of cases of bacterial and fungal keratitis, matched by year, were identified from the same database in order to compare outcomes between the three types of organism. The main outcomes were the time until the following events: re-epithelialization, discontinuation of antimicrobials, perforation/keratoplasty, elevated intraocular pressure, and new cataract.ResultsThe median time until re-epithelialization was 113 days for Acanthamoeba keratitis, 30 days for fungal keratitis, and 25 days for bacterial keratitis, and the median time until discontinuation of antimicrobial therapy was 100 days for Acanthamoeba keratitis, 49 days for fungal keratitis, and 40 days for bacterial keratitis. Compared to the other two organisms, Acanthamoeba ulcers took significantly longer to re-epithelialize (adjusted HR 0.4, 95% CI 0.3 to 0.6 relative to bacterial ulcers and HR 0.3, 95% CI 0.2 to 0.5 relative to fungal ulcers; overall p
- Published
- 2022
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