The Experts below are selected from a list of 2433 Experts worldwide ranked by ideXlab platform
Ian A Cree - One of the best experts on this subject based on the ideXlab platform.
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how could contact lens wearers be at risk of Acanthamoeba Infection a review
Journal of Optometry, 2009Co-Authors: Youhanna W Ibrahim, D L Boase, Ian A CreeAbstract:Contact lens wear is highly influential on the incidence of ulcerative keratitis worldwide, particularly in developed countries. The association between Acanthamoeba keratitis and contact lens wear is firmly established; it may account for up to 95% of the reported cases. Before the popularisation of soft contact lens wear, Acanthamoeba keratitis was extremely rare. In 2000 it was estimated that the number of contact lens wearers worldwide was about 80 million, out of whom 33 million were in the United States and 90% of them wore hydrogel soft lenses. Contact lens-related problems depend on many factors, such as lens material, wearing modality, lens hygiene, type of lens-caring solution, the degree of compliance of the lens user with lens wear and care procedures, lens overwear, sleeping in lenses, rate of changing lenses, and lens case hygiene. This paper is a thorough review of the literature aiming to highlight the role of one of the main risk factors of infectious keratitis, contact lens wear, and also to show the responsibility of lens users in aggravating this risk.
Govinda S Visvesvara - One of the best experts on this subject based on the ideXlab platform.
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Acanthamoeba Infection in a patient with chronic graft versus host disease occurring during treatment with voriconazole
Transplant Infectious Disease, 2008Co-Authors: Daniel R Kaul, Govinda S Visvesvara, L Lowe, S Farmen, Yasser Khaled, G YanikAbstract:We report a case of disseminated Infection with Acanthamoeba in a patient with graft-versus-host disease after hematopoietic stem cell transplant (HSCT) for acute lymphocytic leukemia. The Infection involved the brain, skin, and lungs and occurred despite treatment with voriconazole for mold prophylaxis, and did not respond to treatment with multiple other agents reported to have activity against Acanthamoeba. To our knowledge, Infection with Acanthamoeba has been reported in 4 other patients after HSCTor bone marrow transplant, and our case is the ¢rst to be diagnosed ante- mortem.
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disseminated Acanthamoeba Infection in patients with aids case reports and review
Clinical Infectious Diseases, 1995Co-Authors: Jeanette P Sison, Govinda S Visvesvara, Carol A Kemper, Mark O Loveless, Dennis Mcshane, Stanley C DeresinskiAbstract:Acanthamoeba Infection has been described as an opportunistic Infection in persons with AIDS. We report two cases of patients with AIDS and Acanthamoeba Infection and review the manifestations of this protozoan Infection in patients infected with human immunodeficiency virus. The diagnosis of this Infection requires a high index of suspicion because the clinical and histologic manifestations may be confused with those of disseminated fungal or algal disease. Clinicians and laboratory personnel should be aware of this potentially fatal condition so that appropriate diagnostic studies can be performed and treatment can be urgently administered. Early initiation of therapy may alter the clinical outcome of the disease.
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successful treatment of disseminated Acanthamoeba Infection in an immunocompromised patient
The New England Journal of Medicine, 1994Co-Authors: Cathy A Slater, Joshua Z Sickel, Govinda S Visvesvara, Rufino C Pabico, Anthony A GaspariAbstract:Disseminated Acanthamoeba Infection, an amebic Infection characterized by granulomatous infiltrates in the brain and skin, usually occurs in immunocompromised or debilitated patients and generally progresses to death. There has been no effective therapy. We report on a patient who had undergone renal transplantation and was receiving triple immunosuppressive therapy when widespread granulomatous skin lesions caused by Acanthamoeba rhysodes developed. Antimicrobial therapy was initiated with a four-week course of intravenous pentamidine isethionate, topical chlorhexidine gluconate, and 2 percent ketoconazole cream. The result was a dramatic improvement in the skin lesions. Cyclosporine levels remained stable, but therapy was complicated by signs of . . .
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disseminated Acanthamoeba Infection masquerading as bacillary angiomatosis in a patient with aids case report and literature review
International Journal of Surgical Pathology, 1994Co-Authors: Ghada E Khalife, Govinda S Visvesvara, Stefan E Pambuccian, Bruce HortenAbstract:Disseminated Acanthamoeba Infections and bacillary angiomatosis are among the un usual opportunistic Infections encountered in patients with AIDS. We report a fatal case of disseminated Acanthamoeba palestinensis Infection involving the skin, palate, brain, lungs, and testes in a patient with AIDS in whom the mucocutaneous lesions were initially interpreted clinically and pathologically as bacillary angiomatosis. Int J Surg Pathol 2(1):11-16, 1994
T K Beattie - One of the best experts on this subject based on the ideXlab platform.
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the effect of surface treatment of silicone hydrogel contact lenses on the attachment of Acanthamoeba castellanii trophozoites
Eye & Contact Lens-science and Clinical Practice, 2009Co-Authors: T K Beattie, Alan TomlinsonAbstract:OBJECTIVE: To determine if plasma surface treatment of Focus Night & Day silicone hydrogel contact lenses affects the attachment of Acanthamoeba. METHODS: Unworn lotrafilcon A contact lenses with (Focus Night & Day) and without surface treatment and Acuvue, conventional hydrogel lenses, were quartered before 90-min incubation with Acanthamoeba castellanii trophozoites. After incubation and rinsing, the trophozoites attached to one surface of each quarter were counted by direct light microscopy. Sixteen replicates were observed for each lens type. Logarithmic transformation of data allowed the use of parametric analysis of variance. RESULTS: No significant difference in attachment was established between the untreated lotrafilcon A and the conventional hydrogel lenses (P<0.001); however, surface treatment of the native Focus Night & Day material produced a significant increase in attachment (P<0.001). CONCLUSIONS: Commercially available Focus Night & Day lenses are subjected to a plasma surface treatment to reduce lens hydrophobicity; however, this procedure results in an enhanced Acanthamoebal attachment. It is possible that the silicone hydrogel lens could be at a greater risk of promoting Acanthamoeba Infection if exposed to the organism because of the enhanced attachment characteristic of this material. Eye care professionals should be aware of the enhanced affinity that Acanthamoeba show for this lens and accordingly emphasise to patients the significance of appropriate lens hygiene. This is particularly important where lenses are worn in a regime that could increase the chance of exposure to the organism, i.e., 6 nights/7 days extended wear or daily wear, where lenses will be stored in a lens case, or where lenses are worn when in contact with potentially contaminated water sources, i.e., swimming or showering.
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attachment of Acanthamoeba to first and second generation silicone hydrogel contact lenses
Ophthalmology, 2006Co-Authors: T K Beattie, Alan Tomlinson, Angus McfadyenAbstract:Purpose To investigate the attachment of Acanthamoeba to first- and second-generation silicone hydrogel contact lenses, and to determine if patient wear or the presence of a bacterial biofilm coating affects attachment characteristics. Design Experimental study. Participants and Controls Attachment to the silicone hydrogel lenses was compared with that to a conventional hydrogel control lens. Sixteen replicates (n = 16) were carried out for unworn, worn, and biofilm-coated lenses of each type. Methods Unworn, worn, and Pseudomonas aeruginosa biofilm–coated first-generation (lotrafilcon A) and second-generation (galyfilcon A) silicone hydrogel and conventional hydrogel (etafilcon A) lens quarters were incubated for 90 minutes in suspensions of plate-cultured Acanthamoeba castellanii trophozoites. Main Outcome Measures Trophozoites attached to one surface of each lens quarter were counted by direct light microscopy. Logarithmic transformation of data allowed the use of parametric analysis of variance for statistical analysis. Results Attachment of Acanthamoeba was affected significantly by lens material type ( P P = 0.126). Patient wear and the presence of a bacterial biofilm had no significant effect on attachment to the lotrafilcon A lens ( P = 0.426) but did significantly increase attachment to the galyfilcon A ( P P = 0.009) lenses; attachment to the latter 2 lenses was still significantly less than that found with the first-generation silicone hydrogel ( P Conclusions Acanthamoeba demonstrated a significantly greater affinity for the first-generation silicone hydrogel lens as compared with the second-generation silicone hydrogel and the conventional hydrogel. If exposed to Acanthamoeba (e.g., when showering or swimming, through noncontinuous wear and ineffective lens care regimes), first-generation silicone hydrogel lenses may promote a greater risk of Acanthamoeba Infection due to the enhanced attachment characteristics of this lens material. However, prospective studies in patients are required to determine if these experimental results are clinically significant.
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enhanced attachment of Acanthamoeba to extended wear silicone hydrogel contact lenses a new risk factor for Infection
Ophthalmology, 2003Co-Authors: T K Beattie, Angus Mcfadyen, David V Seal, Alan Tomlinson, A M GrimasonAbstract:Abstract Purpose To establish if silicone hydrogel (S-H) contact lenses could be a risk factor for Acanthamoeba Infection by facilitating the attachment of trophozoites to their surface and transfer to the cornea and to determine the effect Acanthamoeba culture technique, patient wear, and Pseudomonas biofilm coating have on attachment to the S-H lens. Design Experimental material study. Participants and controls Attachment to a S-H lens was compared with that of a conventional hydrogel control lens. Sixteen replicates were carried out for both lens types under each test condition. Methods Unworn S-H (PureVision; Bausch & Lomb, Kingston-Upon-Thames UK) and conventional hydrogel (Acuvue; Vistakon, Johnson & Johnson, Jacksonville, FL USA) lens quarters were incubated for 90 minutes in suspensions of liquid or plate-cultured Acanthamoeba castellanii trophozoites. Unworn, worn, and Pseudomonas biofilm coated S-H and hydrogel quarters were incubated for 90 minutes with plate-cultured trophozoites. Main outcome measures Trophozoites attached to one surface of each lens quarter were counted by direct light microscopy. Logarithmic transformation of data allowed the use of a parametric analysis of variance. Results Lens polymer had a significant effect on attachment ( P P = 0.013), with higher numbers of liquid-cultured organisms attaching to both lens types. A significant increase in attachment was demonstrated with worn and Pseudomonas biofilm-coated hydrogel lenses ( P Conclusions Acanthamoebal attachment to the S-H lenses was significantly greater than to the conventional hydrogel. Liquid-cultured trophozoites demonstrated a higher affinity for the lenses tested. Wear and bacterial biofilm coating had no effect on attachment to S-H lenses. The increased attachment found with the S-H lens may be an inherent characteristic of the polymer or a side effect of the surface treatment procedure to which the lenses are exposed. It is possible that S-H lenses are at greater risk of promoting Acanthamoeba Infection if exposed to the organism because of the enhanced attachment characteristic of this new material.
Angus Mcfadyen - One of the best experts on this subject based on the ideXlab platform.
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attachment of Acanthamoeba to first and second generation silicone hydrogel contact lenses
Ophthalmology, 2006Co-Authors: T K Beattie, Alan Tomlinson, Angus McfadyenAbstract:Purpose To investigate the attachment of Acanthamoeba to first- and second-generation silicone hydrogel contact lenses, and to determine if patient wear or the presence of a bacterial biofilm coating affects attachment characteristics. Design Experimental study. Participants and Controls Attachment to the silicone hydrogel lenses was compared with that to a conventional hydrogel control lens. Sixteen replicates (n = 16) were carried out for unworn, worn, and biofilm-coated lenses of each type. Methods Unworn, worn, and Pseudomonas aeruginosa biofilm–coated first-generation (lotrafilcon A) and second-generation (galyfilcon A) silicone hydrogel and conventional hydrogel (etafilcon A) lens quarters were incubated for 90 minutes in suspensions of plate-cultured Acanthamoeba castellanii trophozoites. Main Outcome Measures Trophozoites attached to one surface of each lens quarter were counted by direct light microscopy. Logarithmic transformation of data allowed the use of parametric analysis of variance for statistical analysis. Results Attachment of Acanthamoeba was affected significantly by lens material type ( P P = 0.126). Patient wear and the presence of a bacterial biofilm had no significant effect on attachment to the lotrafilcon A lens ( P = 0.426) but did significantly increase attachment to the galyfilcon A ( P P = 0.009) lenses; attachment to the latter 2 lenses was still significantly less than that found with the first-generation silicone hydrogel ( P Conclusions Acanthamoeba demonstrated a significantly greater affinity for the first-generation silicone hydrogel lens as compared with the second-generation silicone hydrogel and the conventional hydrogel. If exposed to Acanthamoeba (e.g., when showering or swimming, through noncontinuous wear and ineffective lens care regimes), first-generation silicone hydrogel lenses may promote a greater risk of Acanthamoeba Infection due to the enhanced attachment characteristics of this lens material. However, prospective studies in patients are required to determine if these experimental results are clinically significant.
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enhanced attachment of Acanthamoeba to extended wear silicone hydrogel contact lenses a new risk factor for Infection
Ophthalmology, 2003Co-Authors: T K Beattie, Angus Mcfadyen, David V Seal, Alan Tomlinson, A M GrimasonAbstract:Abstract Purpose To establish if silicone hydrogel (S-H) contact lenses could be a risk factor for Acanthamoeba Infection by facilitating the attachment of trophozoites to their surface and transfer to the cornea and to determine the effect Acanthamoeba culture technique, patient wear, and Pseudomonas biofilm coating have on attachment to the S-H lens. Design Experimental material study. Participants and controls Attachment to a S-H lens was compared with that of a conventional hydrogel control lens. Sixteen replicates were carried out for both lens types under each test condition. Methods Unworn S-H (PureVision; Bausch & Lomb, Kingston-Upon-Thames UK) and conventional hydrogel (Acuvue; Vistakon, Johnson & Johnson, Jacksonville, FL USA) lens quarters were incubated for 90 minutes in suspensions of liquid or plate-cultured Acanthamoeba castellanii trophozoites. Unworn, worn, and Pseudomonas biofilm coated S-H and hydrogel quarters were incubated for 90 minutes with plate-cultured trophozoites. Main outcome measures Trophozoites attached to one surface of each lens quarter were counted by direct light microscopy. Logarithmic transformation of data allowed the use of a parametric analysis of variance. Results Lens polymer had a significant effect on attachment ( P P = 0.013), with higher numbers of liquid-cultured organisms attaching to both lens types. A significant increase in attachment was demonstrated with worn and Pseudomonas biofilm-coated hydrogel lenses ( P Conclusions Acanthamoebal attachment to the S-H lenses was significantly greater than to the conventional hydrogel. Liquid-cultured trophozoites demonstrated a higher affinity for the lenses tested. Wear and bacterial biofilm coating had no effect on attachment to S-H lenses. The increased attachment found with the S-H lens may be an inherent characteristic of the polymer or a side effect of the surface treatment procedure to which the lenses are exposed. It is possible that S-H lenses are at greater risk of promoting Acanthamoeba Infection if exposed to the organism because of the enhanced attachment characteristic of this new material.
G S Visvesvara - One of the best experts on this subject based on the ideXlab platform.
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Acanthamoeba Infection presenting as skin lesions in patients with the acquired immunodeficiency syndrome
Archives of Pathology & Laboratory Medicine, 1993Co-Authors: B Tan, C M Weldonlinne, D P Rhone, C L Penning, G S VisvesvaraAbstract:Acanthamoeba organisms are a well-known, although rare, cause of central nervous system Infection in immunodeficient hosts, including those with the acquired immunodeficiency syndrome. Extracerebral acanthamebiasis, with the exception of contact lens-associated keratitis, is reported but little emphasized in the literature. We describe two patients with the acquired immunodeficiency syndrome in whom skin lesions were the primary manifestations of Acanthamoeba Infection. Central nervous system disease was proved in one patient and suspected, but unproved, in the other. The skin lesions exhibited an intact epidermis with suppurative inflammation of the subcutis, associated with numerous amebic cysts and trophozoites. The amebic cyst walls stained with periodic acid-Schiff and Gomori's methenamine-silver stains, creating confusion with Blastomyces dermatitidis yeast in one instance. Immunofluorescence studies and culture identified the organisms as an Acanthamoeba species. Preliminary studies in one of the cases suggested a previously undescribed Acanthamoeba species as the etiologic agent. Our experience emphasizes that skin lesions may be the presenting sign of disseminated Acanthamoeba Infection in patients with the acquired immunodeficiency syndrome.
