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Carnt N, Hoffman JJ, Verma S, Hau S, Radford CF, Minassian DC, Dart JKG. Acanthamoeba keratitis: confirmation of the UK outbreak and a prospective case-control study identifying contributing risk factors. Br J Ophthalmol 2018; 102:1621-1628. [PMID: 30232172 DOI: 10.1136/bjophthalmol-2018-312544] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 07/27/2018] [Accepted: 08/07/2018] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS Acanthamoeba keratitis (AK) is a chronic debilitating corneal infection principally affecting contact lens (CL) users. Studies were designed to test claims that the UK incidence may have increased in 2012-2014 and to evaluate potential causes. METHODS Annualised incidence data were collected from January 1984 to December 2016. Case-control study subjects were recruited between 14 April 2011 and 05 June 2017. Reusable CL users with AK were recruited retrospectively and prospectively. Controls were reusable CL users, recruited prospectively, with any disorder other than AK. Multivariable analysis of questionnaire data measured independent risk factors for AK. RESULTS The current outbreak of AK started in 2010-2011 with an incidence threefold higher than in 2004-2009. Risk factors for AK were: Oxipol disinfection, CLs made of group IV CL materials, poor CL hygiene, deficient hand hygiene, use of CLs while swimming or bathing, being white British, and for those in social classes 4-9. CONCLUSION AK is a largely preventable disease. The current outbreak is unlikely to be due to any one of the identified risk factors in isolation. Improving CL and hand hygiene, avoiding CLs contamination with water and use of effective CL disinfection solutions, or daily disposable CLs, will reduce the incidence of AK. In the longer-term, water avoidance publicity for CL users can be expected to reduce the incidence further. Ongoing surveillance of AK numbers will identify changes in incidence earlier. Evaluation of Acanthamoeba contamination in end-user drinking water would contribute to our understanding of regional variations in the risk of exposure.
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Affiliation(s)
- Nicole Carnt
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.,Centre for Vision Research, Westmead Institute for Medical Research, Westmead, Australia.,Corneal and External Disease Service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Jeremy J Hoffman
- Corneal and External Disease Service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Seema Verma
- Corneal and External Disease Service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Scott Hau
- Corneal and External Disease Service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Cherry F Radford
- Corneal and External Disease Service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | | | - John K G Dart
- Corneal and External Disease Service, Moorfields Eye Hospital NHS Foundation Trust, London, UK .,National Institute of Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
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Huang FC, Shih MH, Chang KF, Huang JM, Shin JW, Lin WC. Characterizing clinical isolates of Acanthamoeba castellanii with high resistance to polyhexamethylene biguanide in Taiwan. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2017; 50:570-577. [DOI: 10.1016/j.jmii.2015.10.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 07/01/2015] [Accepted: 10/22/2015] [Indexed: 11/16/2022]
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Huang FC, Liu TS, Li SC, Shih MH, Shin JW, Lin WC. The effect of the disulfideisomerase domain containing protein in the defense against polyhexamethylene biguanide of highly tolerant Acanthamoeba at the trophozoite stage. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2016; 6:251-257. [PMID: 27888770 PMCID: PMC5124359 DOI: 10.1016/j.ijpddr.2016.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/10/2016] [Accepted: 11/11/2016] [Indexed: 11/25/2022]
Abstract
Acanthamoeba castellanii is a free-living protozoan pathogen capable of causing a blinding keratitis and fatal granulomatous encephalitis. Current treatment generally involves an hourly application of polyhexamethylene biguanide (PHMB) over a period of several days but this is not entirely effective against all strains/isolates. The tolerance mechanisms of PHMB in Acanthamoeba cells remain unclear. In this study, we found that the mRNA expression level of disulfideisomerase domain containing protein (PDI) increased rapidly in surviving cells of the highly PHMB-tolerant Acanthamoeba castellanii strain, NCKH_D, during PHMB treatment, but not in the ATCC standard strain. After PDI-specific silencing, NCKH_D was found to be more vulnerable to PHMB treatment. The results described above show that PDI is an important gene for PHMB tolerance ability in a highly PHMB-tolerant strain of Acanthamoeba and provide a new insight for more efficient medicine development for Acanthamoeba keratitis.
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Affiliation(s)
- Fu-Chin Huang
- Department of Ophthalmology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Tao-Shen Liu
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Sung-Chou Li
- Genomics and Proteomics Core Laboratory, Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Min-Hsiu Shih
- Department of Ophthalmology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jyh-Wei Shin
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Parasitology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Chen Lin
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Parasitology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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Bang S, Edell E, Eghrari AO, Gottsch JD. Treatment with voriconazole in 3 eyes with resistant Acanthamoeba keratitis. Am J Ophthalmol 2010; 149:66-9. [PMID: 19875089 DOI: 10.1016/j.ajo.2009.08.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 08/04/2009] [Accepted: 08/05/2009] [Indexed: 11/30/2022]
Abstract
PURPOSE To report the use of topical voriconazole 1% (Vfend; Pfizer Inc, New York, New York, USA) ophthalmic solution for Acanthamoeba keratitis (AK) resistant to treatment with chlorhexidine (PerioChip; Dexel Pharma Technologies, Jerusalem, Israel). DESIGN Retrospective case series. METHODS Three eyes of 2 patients with culture-proven AK were treated at a tertiary care institution, and their charts were reviewed. Topical voriconazole 1% was instituted as second-line treatment for AK unresponsive to standard treatment with chlorhexidine and hexamidine. Treatment with voriconazole 1% was started at 1-hour intervals. Improvement was assessed and defined by absence of clinical signs of active infection and visual improvement. RESULTS One patient with unilateral AK and 1 patient with bilateral AK who remained culture-positive for Acanthamoeba despite ongoing treatment with chlorhexidine and hexamidine were treated with voriconazole 1% topical solution as an adjuvant. Both patients were contact lens wearers. Of 3 eyes additionally treated with voriconazole, 2 eyes had clinical resolution of disease. One eye demonstrated recurrent disease after penetrating keratoplasty that resolved after intrastromal injection of voriconazole. CONCLUSIONS We report the use of topical and intrastromal voriconazole in successfully treating AK in cases of chlorhexidine- and hexamidine-resistant Acanthamoeba. Voriconazole may be a promising adjuvant agent in treating AK.
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Affiliation(s)
- Stacy Bang
- Cataract, Cornea and External Disease Service, Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland, USA
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5
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Choy CKM, Cho P, Boost MV, Benzie IFF. Do multipurpose solutions damage porcine corneal epithelial cells? Optom Vis Sci 2009; 86:E447-53. [PMID: 19319011 DOI: 10.1097/opx.0b013e31819fa422] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To determine and compare the cytotoxic effects on porcine corneal epithelial cells of commercially available multipurpose solutions (MPS) using fluorescein staining and flow cytometry (FCM). METHODS Effects of exposure time of 10 s to 10 min of MPS containing polyquaternium-1 (MPS-A), polyaminopropyl biguanide (MPS-B), and polyhexanide (MPS-C), on porcine corneal epithelial cells were determined. Cell viability and membrane integrity were assessed by Annexin V-FITC/7-AAD staining and FCM. In further trials, whole corneas were immersed in MPS and control (buffered saline), and corneal fluorescein staining assessed before FCM analysis. RESULTS Significantly higher percentages of 7-AAD-stained cells (early necrosis) were observed at all exposure times for MPS-A than for other solutions and control (p < 0.05). Exposure time in MPS-A and 7-AAD-stained cell proportions showed significant correlation (r = 0.9957; p < 0.0001). Significantly more cells dual-stained with Annexin V-FITC/7-AAD (late necrosis) after 5 min MPS-A exposure (11.8 +/- 1.1%), compared with 1.2 +/- 0.9% (MPS-B), 0.9 +/- 0.5% (MPS-C), and 1.8 +/- 0.2% (control). However, only 10 min exposure resulted in significant increases in fluorescein grades (p < 0.001), with median grade 0.75 for MPS-A, and 0.50 for the other MPS. CONCLUSIONS MPS exposure, especially MPS-A, affected the viability and integrity of porcine corneal epithelial cells. Furthermore, our results confirmed that fluorescein staining correlates poorly with cytotoxicity. As fluorescein staining lacks sensitivity to determine cytotoxic effects of ophthalmic solutions, more objective and sensitive assessment methods such as differential staining and FCM should be developed.
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Affiliation(s)
- Camus Kar Man Choy
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, PR China
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Boggild AK, Martin DS, Lee TY, Yu B, Low DE. Laboratory diagnosis of amoebic keratitis: comparison of four diagnostic methods for different types of clinical specimens. J Clin Microbiol 2009; 47:1314-8. [PMID: 19321727 PMCID: PMC2681827 DOI: 10.1128/jcm.00173-09] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 03/09/2009] [Accepted: 03/16/2009] [Indexed: 11/20/2022] Open
Abstract
Amoebic keratitis causes significant ocular morbidity in contact lens wearers. Current diagnostic methods for amoebic keratitis are insensitive and labor-intensive and have poor turnaround time. We evaluated four laboratory methods for detection of acanthamoebae in clinical specimens. Deidentified, delinked consecutive specimens from patients with suspected amoebic keratitis were assayed for acanthamoebae by direct smear analysis, culture, and PCR using two different primer sets specific for Acanthamoeba ribosomal DNA. The consensus reference standard was considered fulfilled when the results for any two of the four tests were positive, and the outcome measures were sensitivity and specificity. Of 107 specimens assayed over an 18-month period, 20 were positive for acanthamoebae. The sensitivity and specificity of each assay were as follows, respectively: for smear analysis, 55% (95% confidence interval [CI], 33.2 to 76.8%) and 100%; for culture, 73.7% (95% CI, 54.4 to 93.0%) and 100%; for PCR using Nelson primers, 90% (95% CI, 76.9 to 100%) and 90.8% (95% CI, 84.7 to 96.9%); and for PCR using JDP primers, 65% (95% CI, 44.1 to 85.9%) and 100%. Nelson primer PCR demonstrated a single-organism level of analytic sensitivity. The performance characteristics of the assays varied by specimen type, with contact lenses and casings showing the highest rates of detectable acanthamoebae and the highest diagnostic sensitivities for direct smear analysis, culture, and JDP primer PCR, though these results are based on small numbers and should be interpreted cautiously. These findings have important implications for clinicians collecting diagnostic specimens and for diagnostic laboratories, especially in outbreak situations.
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Affiliation(s)
- Andrea K Boggild
- Tropical Diseases Unit, Toronto General Hospital, Toronto, Ontario, Canada.
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Voyatzis G, McElvanney A. Bilateral Acanthamoeba keratitis in an experienced two-weekly disposable contact lens wearer. Eye Contact Lens 2007; 33:201-2. [PMID: 17630630 DOI: 10.1097/01.icl.0000252567.06446.7b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To present a case of bilateral Acanthamoeba keratitis in a patient who stored both contact lenses in the same storage case. METHODS The case report of a 44-year-old female contact lens wearer who developed bilateral culture-positive Acanthamoeba keratitis. Although an experienced contact lens user for many years, she admitted to occasionally rinsing her dual contact lens case in tap water and leaving it to air dry. She was successfully treated with intensive topical polyhexamethyl biguanide and propamide isethionate in conjunction with a mydriatic agent, topical ofloxacin, and oral flurbiprofen. RESULTS The Acanthamoeba keratitis resolved without sequelae. After 6 months, the patient had a visual acuity of 20/20 in each eye. CONCLUSIONS Although bilateral Acanthamoeba keratitis is rare, it is essential that the patient is properly educated in contact lens hygiene and disinfection. Regular contact lens follow-up of patients is essential, and lens storage and disinfection techniques must be reviewed with the patient. The use of single-use contact lens storage cases may be advantageous in reducing the incidence of bilateral disease after case contamination.
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Affiliation(s)
- George Voyatzis
- Epsom and St. Helier University Hospitals, Surrey, United Kingdom.
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Ibrahim YW, Boase DL, Cree IA. Factors affecting the epidemiology of Acanthamoeba keratitis. Ophthalmic Epidemiol 2007; 14:53-60. [PMID: 17464851 DOI: 10.1080/09286580600920281] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Despite being a relatively rare disease in comparison with other forms of infectious keratitis, Acanthamoeba keratitis is a potentially blinding disease. Wide variations in the incidence of Acanthamoeba keratitis have been reported in both developed and developing countries. At the same time that contact lens wear was found to be responsible for the spread of the disease in developed countries, Acanthamoeba keratitis was considered a rare disease in developing countries compared with fungal and bacterial keratitis. In recent decades, the risk of getting Acanthamoeba keratitis has increased because of the increased proportion of contact lens wearers. This article introduces the different factors affecting the epidemiology of Acanthamoeba keratitis worldwide, presents a chronological review of the literature, and shows the progressive spread of Acanthamoeba keratitis in the last two decades in different geographical areas of the world. A detailed comparison of the incidence of the disease as reported in different studies in different countries is made. The impact of contact lenses and other factors, such as hot weather, virulence of Acanthamoeba strains, water sanitation and quality, the occurrence of environmental disasters such as flooding, and the wide environmental presence of Acanthamoeba cysts on the incidence of the disease, are discussed. In addition, the ability of Acanthamoeba cysts to resist different harsh conditions is reviewed.
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Affiliation(s)
- Youhanna W Ibrahim
- Department of Ophthalmology, Queen Alexandra Hospital, Portsmouth, United Kingdom.
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Clarke DW, Niederkorn JY. The pathophysiology of Acanthamoeba keratitis. Trends Parasitol 2006; 22:175-80. [PMID: 16500148 DOI: 10.1016/j.pt.2006.02.004] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 01/04/2006] [Accepted: 02/07/2006] [Indexed: 11/16/2022]
Abstract
Acanthamoeba keratitis is a sight-threatening infection of the ocular surface that is produced by several free-living amebae of the genus Acanthamoeba. Infection is usually initiated by Acanthamoeba-contaminated contact lenses and produces exquisite pain and ulceration of the ocular surface. The pathophysiology of this infection involves an intricate series of sequential events that includes the production of several pathogenic proteases that degrade basement membranes and induce cytolysis and apoptosis of the cellular elements of the cornea, culminating in dissolution of the collagenous corneal stroma. Targeting such proteases could lead to the development of vaccines that target the disease process rather than the pathogen itself.
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Affiliation(s)
- Daniel W Clarke
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9057, USA
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10
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Campos-Rodríguez R, Oliver-Aguillón G, Vega-Pérez LM, Jarillo-Luna A, Hernández-Martínez D, Rojas-Hernández S, Rodríguez-Monroy MA, Rivera-Aguilar V, González-Robles A. Human IgA inhibits adherence of Acanthamoeba polyphaga to epithelial cells and contact lenses. Can J Microbiol 2005; 50:711-8. [PMID: 15644925 DOI: 10.1139/w04-057] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Specific anti-Acanthamoeba IgA antibodies have been detected in the serum and tears of patients and healthy individuals. However, the role of human secretory IgA antibodies in inhibiting the adherence of Acanthamoeba had not been previously investigated. Therefore, the purpose of this study was to purify secretory IgA from human colostrum and analyze its effect on the adherence of Acanthamoeba trophozoites to contact lenses and Madin-Darby canine kidney (MDCK) cells. IgA antibodies to Acanthamoeba polyphaga in colostrum of healthy women as well as in saliva and serum of healthy subjects were analyzed by ELISA and Western blot analysis. In serum, saliva, and colostrum, we detected IgA antibodies that recognized several antigens of A. polyphaga. In addition, colostrum and IgA antibodies purified from it inhibited adherence of A. polyphaga trophozoites to contact lenses and MDCK cells. These results suggest that IgA antibodies may participate in the resistance to the amoebic infection, probably by inhibiting the adherence of the trophozoites to contact lenses and corneal epithelial cells.
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Affiliation(s)
- Rafael Campos-Rodríguez
- Department of Biochemistry, School of Medicine, National Polytechnic Institute, Plan de San Luis y Díaz Mirón, Mexico
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Antimicrobial efficacy of a povidone iodine (PI) and a one-step hydrogen peroxide contact lens disinfection system. Cont Lens Anterior Eye 2004. [DOI: 10.1016/j.clae.2004.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Hurt M, Neelam S, Niederkorn J, Alizadeh H. Pathogenic Acanthamoeba spp secrete a mannose-induced cytolytic protein that correlates with the ability to cause disease. Infect Immun 2003; 71:6243-55. [PMID: 14573643 PMCID: PMC219557 DOI: 10.1128/iai.71.11.6243-6255.2003] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pathogenesis of Acanthamoeba keratitis begins when Acanthamoeba trophozoites bind specifically to mannosylated glycoproteins upregulated on the surfaces of traumatized corneal epithelial cells. When Acanthamoeba castellanii trophozoites are grown in methyl-alpha-D-mannopyranoside, they are induced to secrete a novel 133-kDa protein that is cytolytic to corneal epithelial cells. Clinical isolates of Acanthamoeba spp., and not the soil isolates, were proficient at producing a mannose-induced protein (MIP-133) and generating disease in Chinese hamsters. The purified protein was efficient at killing corneal epithelial cells, the first mechanistic barrier, by inducing apoptosis in a caspase 3-dependent pathway. Subsequent steps in pathogenesis require the amoebae to penetrate and degrade collagen. Only the clinical isolates tested were efficient at migrating through a collagenous matrix in vitro, presumably by MIP-133 degradation of both human type I and human type IV collagen. A chicken anti-MIP-133 antiserum effectively bound to the protein and blocked collagenolytic activity, migration, and cytopathic effects (CPE) against corneal cells in vitro. Chinese hamsters orally immunized with MIP-133 displayed a >30% reduction in disease. Immunoglobulin A isolated from immunized animals bound MIP-133 and blocked CPE on corneal cells in vitro. Animals induced to generate severe chronic infections displayed significant reductions in disease symptoms upon oral immunization postinfection. These data suggest that MIP-133 production might be necessary to initiate corneal disease and that it may play an important role in the subsequent steps of the pathogenic cascade of Acanthamoeba keratitis. Furthermore, as antibodies produced both prior to and after infection reduced clinical symptoms of disease, the protein may represent an important immunotherapeutic target for Acanthamoeba keratitis.
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Affiliation(s)
- Michael Hurt
- Department of Ophthalmology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA
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Benedetto N, Rossano F, Gorga F, Folgore A, Rao M, Romano Carratelli C. Defense mechanisms of IFN-gamma and LPS-primed murine microglia against Acanthamoeba castellanii infection. Int Immunopharmacol 2003; 3:825-34. [PMID: 12781699 DOI: 10.1016/s1567-5769(03)00047-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In the central nervous system (CNS), cytokine-primed microglia play a central role in host's defense against Acanthamoeba castellanii infection. In this study, the effect of recombinant interferon (rIFN)-gamma and Salmonella enterica serovar enteritidis lipopolysaccharide (LPS), both inflammatory stimuli, on A. castellanii infection in murine microglia was examined. Priming of microglia with rIFN-gamma and LPS synergistically triggered, in a dose-dependent manner, amebastatic activity in these cells. More than 52%, 88% or 95% of this function was then abrogated by anti-IL-1beta (but not anti-IL-1alpha), IL-6 or TNF-alpha neutralizing antibodies, suggesting that these endogenously produced cytokines may participate in the antimicrobial capacity. Consistent with these findings, the priming of microglia with rIFN-gamma and LPS elicited the release of proinflammatory interleukin (IL)-1alpha, IL-1beta, IL-6 and tumor necrosis factor (TNF)-alpha. Since L-canavanine affected amebastatic activity only during the priming process but not during the infection process, NO-dependent pathway appears to be not the sole antiparasitic mechanism involved in this function. These data suggest that rIFN-gamma and LPS, likely through a proinflammatory network, up-regulate the release of IL-beta, IL-6 and TNF-alpha, which could trigger antimicrobial activity against A. castellanii infection in the brain.
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Affiliation(s)
- N Benedetto
- Section of Microbiology and Clinical Microbiology, Department of Experimental Medicine, Faculty of Medicine and Surgery, Second University of the Studies of Naples, Naples, Italy.
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Radford CF, Minassian DC, Dart JKG. Acanthamoeba keratitis in England and Wales: incidence, outcome, and risk factors. Br J Ophthalmol 2002; 86:536-42. [PMID: 11973250 PMCID: PMC1771120 DOI: 10.1136/bjo.86.5.536] [Citation(s) in RCA: 243] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIM To determine the incidence, regional variation in frequency, outcome, and risk factors for acanthamoeba keratitis (AK) in England and Wales. METHODS AK cases presenting from 1 October 1997 to 30 September 1999 were identified by the British Ophthalmic Surveillance Unit active reporting system. Clinical and patient postal questionnaire data were analysed. RESULTS 106 reported cases met study criteria. The annual incidence for the 2 years was 1.26 and 1.13 per million adults and, for contact lens (CL) wearers, 21.14 and 17.53 per million. There was marked regional variation in incidence (0 to 85.13 per million adult CL wearers), with CL wearers in the south having a ninefold increased risk of AK compared with those resident in the north (95% confidence limits: 2.2-38.9, p<0.0001), and a threefold increased risk with hard as opposed to soft domestic water (95% confidence limits: 1.73 to 6.58, p<0.001). Treatment and outcome data were similar to those previously reported. 93/106 (88%) patients were CL wearers. Among these, 46/77 (60%) were disinfecting irregularly, and 20/63 (32%) had been swimming in CLs. One step hydrogen peroxide and chlorine release soft CL (SCL) disinfection systems were significantly over-represented among the cases. Among SCL users, one or more previously established risk factors for AK were identified in 50/55 (91%) patients. CONCLUSIONS The incidence was considerably higher than most previous estimates, and was static. The geographical variation in incidence may be partly related to the increase in risk associated with hard water. The fact that water quality can have such an effect on the risk of AK suggests that many CL wearers must be letting tapwater come into contact with their lenses or storage cases. Improved education for CL wearers and practitioners about hygiene practice and the variable efficacy of contact lens systems could be expected to reduce the incidence of this disease.
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Affiliation(s)
- C F Radford
- Moorfields Eye Hospital, London, UK. cherry.radford.ukgateway.net
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Alizadeh H, Apte S, El-Agha MS, Li L, Hurt M, Howard K, Cavanagh HD, McCulley JP, Niederkorn JY. Tear IgA and serum IgG antibodies against Acanthamoeba in patients with Acanthamoeba keratitis. Cornea 2001; 20:622-7. [PMID: 11473164 DOI: 10.1097/00003226-200108000-00013] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE Exposure to Acanthamoebaspecies appears to be ubiquitous, as 50% to 100% of healthy human subjects display anti-Acanthamoebaantibodies. However, the presence of specific anti-Acanthamoebaantibodies in the serum and tears of patients has not been investigated. The prevalence of serum immunoglobulin G (IgG) and tear IgA against three species of Acanthamoebawas assessed in healthy subjects and patients with Acanthamoebakeratitis. METHODS The level of specific serum IgG and tear IgA against A. castellanii, A. astronyxis, and A. culbertsoniin the sera of 23 patients and 25 healthy subjects was tested by enzyme-linked immunosorbent assays. Total serum IgM, IgG, and IgA concentrations were measured by nephelometry. Acanthamoebakeratitis was diagnosed clinically and confirmed by in vivo confocal microscopy. In some patients, corneal biopsies were also performed and trophozoites were cultured on lawns of Escherichia colion non-nutrient agar. RESULTS All healthy subjects and patients with Acanthamoebakeratitis had detectable serum IgG antibodies against all Acanthamoebaantigens. However, patients with Acanthamoebakeratitis had significantly higher anti-AcanthamoebaIgG antibody titers than healthy subjects. In contrast, Acanthamoeba-specific tear IgA was significantly lower in patients with Acanthamoebakeratitis in comparison with healthy subjects. Total serum immunoglobulins did not differ significantly between healthy subjects and patients with Acanthamoebakeratitis. CONCLUSIONS The results suggest that a low level of anti-AcanthamoebaIgA antibody in the tears appears to be associated with Acanthamoebakeratitis.
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Affiliation(s)
- H Alizadeh
- Department of Ophthalmology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA.
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Jongwutiwes S, Pariyakanok L, Charoenkorn M, Yagita K, Endo T. Heterogeneity in cyst morphology within isolates of Acanthamoeba from keratitis patients in Thailand. Trop Med Int Health 2000; 5:335-40. [PMID: 10886796 DOI: 10.1046/j.1365-3156.2000.00563.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We isolated Acanthamoebae from the first two keratitis patients identified in Thailand in 1988 and 1990. The patients developed decreased vision, severe photophobia, severe eye pain and foreign body sensation after minor corneal trauma. The lesions included generalized superficial punctate keratitis, stromal corneal ulcer with keratic precipitate and uveitis in one case, and corneal ulcer with abscess in the other. Both cases were diagnosed by isolation of characteristic trophozoites and cysts of Acanthamoeba from corneal tissue by non-nutrient agar culture method. Based on cyst morphology, A. castellanii and A. polyphaga were detected in one case, and A. castellanii and A. triangularis in the other. Restriction fragment length polymorphism analysis of mitochondrial DNA (mtDNA-RFLP) revealed that each patient harboured a single parasite population. One shared mtDNA-RFLP with an authentic strain of A. castellanii, and the other gave a new unique pattern. Thus species identification of Acanthamoeba based on cyst morphology per se can be arbitrary, and mtDNA-RFLP may be more appropriate for accurate species/strain differentiation amongst morphologically heterogeneous populations of Acanthamoebae.
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Affiliation(s)
- S Jongwutiwes
- Department of Parasitology, Chulalongkorn University, Bangkok, Thailand.
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Radford CF, Dart JK. Letter to the editor. Cont Lens Anterior Eye 1999; 22:34-5; author reply 36-8. [PMID: 16303402 DOI: 10.1016/s1367-0484(99)80033-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sharma S, Sankaridurg PR, Venkata N, Potluri S, Athmanathan S, Reddy S, Holden BA, Rao GN. Adherence of Acanthamoeba to human corneal epithelial cells recovered from normal non-lens wearers and asymptomatic contact lens wearers. Cont Lens Anterior Eye 1999; 22:110-5. [PMID: 16303415 DOI: 10.1016/s1367-0484(99)80011-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/1999] [Revised: 06/27/1999] [Indexed: 11/28/2022]
Abstract
To increase our knowledge of factors leading to Acanthamoeba keratitis in contact lens wearers, we determined the ability of this organism to adhere to corneal epithelial cells (EC) recovered from non-lens wearers (NL) and from subjects using hydrogel contact lenses on a daily (DW) and extended wear (EW) schedule. ECs were incubated with trophozoites of Acanthamoeba and, after 3 h, the median per cent of cells exhibiting adherence was 24, 23 and 23 for NL, DW and EW groups respectively (P=0.552, Kruskal-Wallis Test). There were no differences between the groups for the number of adherent amoebae and a significant majority had only one adherent trophozoite per EC. No difference in adherence was seen with increasing exposure time. Factors other than amoebic adherence to superficial corneal EC are responsible for the increased incidence of Acanthamoeba keratitis in lens wearers.
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Affiliation(s)
- S Sharma
- L.V. Prasad Eye Institute, Hyderabad, India.
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Stevenson R, Seal D. Authors' reply. Cont Lens Anterior Eye 1999. [DOI: 10.1016/s1367-0484(99)80034-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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