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Kaufman AR, Tu EY. Advances in the management of Acanthamoeba keratitis: A review of the literature and synthesized algorithmic approach. Ocul Surf 2022; 25:26-36. [DOI: 10.1016/j.jtos.2022.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 04/10/2022] [Accepted: 04/12/2022] [Indexed: 01/01/2023]
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Bradley CS, Sicks LA, Pucker AD. Common Ophthalmic Preservatives in Soft Contact Lens Care Products: Benefits, Complications, and a Comparison to Non-Preserved Solutions. CLINICAL OPTOMETRY 2021; 13:271-285. [PMID: 34522149 PMCID: PMC8434857 DOI: 10.2147/opto.s235679] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/24/2021] [Indexed: 05/23/2023]
Abstract
PURPOSE Preservatives are essential for preventing contact lens (CL)-related microbial keratitis (MK). The purpose of this review is to summarize the current knowledge related to the use of common ophthalmic preservatives in CL care products with respect to both safety and efficacy. METHODS Manuscripts written in English were obtained by searching PubMed.gov with the term contact lens plus antimicrobial, benzalkonium chloride, biguanide, Aldox, polyquaternium, preservative, thimerosal, EDTA (ethylenediaminetetraacetic acid), chlorhexidine, or blister pack. RESULTS This review found that first-generation preservatives are no longer used in CL multipurpose solutions (MPS) due to their high levels of ocular toxicity. Modern, high-molecular-weight preservatives, including polyquaternium-1 (PQ-1) and biguanides (PHMB), are generally effective against bacteria, minimally effective against fungi, and not effective against Acanthamoeba. PQ-1 and PHMB are likely safe when used with CLs, but they may cause ocular adverse events, with roughly equal risk between the two preservatives. Some CL MPS contain both PQ-1 and PHMB, but no increased risk of adverse events has been reported when combining the two. Hydrogen-peroxide (H2O2) solutions are effective against all common ocular microbes, including Acanthamoeba, and they have been proven safe with proper compliance. Povidone-iodine (P-I) solutions are not currently commercially available in North America, but they have been shown in other countries to be safe and effective. CONCLUSION Patients should be monitored when using PQ-1 or PHMB-containing solutions since they have been associated with ocular adverse events. If events are detected, patients should be switched to an alternative solution. H2O2 or P-I solutions are preferred for any patient who may expose their CLs to water because they are the only solution categories effective against Acanthamoeba.
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Affiliation(s)
| | | | - Andrew D Pucker
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
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Lindsay RG, Watters G, Johnson R, Ormonde SE, Snibson GR. Acanthamoeba keratitis and contact lens wear. Clin Exp Optom 2021; 90:351-60. [PMID: 17697181 DOI: 10.1111/j.1444-0938.2007.00172.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Acanthamoeba keratitis is a rare but serious complication of contact lens wear that may cause severe visual loss. The clinical picture is usually characterised by severe pain, sometimes disproportionate to the signs, with an early superficial keratitis that is often misdiagnosed as herpes simplex virus (HSV) keratitis. Advanced stages of the infection are usually characterised by central corneal epithelial loss and marked stromal opacification with subsequent loss of vision. In this paper, six cases of contact lens-related Acanthamoeba keratitis that occurred in Australia and New Zealand over a three-year period are described. Three of the patients were disposable soft lens wearers, two were hybrid lens wearers and one was a rigid gas permeable lens wearer. For all six cases, the risk factors for Acanthamoeba keratitis were contact lens wear with inappropriate or ineffective lens maintenance and exposure of the contact lenses to tap or other sources of water. All six patients responded well to medical therapy that involved topical use of appropriate therapeutic agents, most commonly polyhexamethylene biguanide and propamidine isethionate, although two of the patients also subsequently underwent deep lamellar keratoplasty due to residual corneal surface irregularity and stromal scarring. Despite the significant advances that have been made in the medical therapy of Acanthamoeba keratitis over the past 10 years, prevention remains the best treatment and patients who wear contact lenses must be thoroughly educated about the proper use and care of the lenses. In particular, exposure of the contact lenses to tap water or other sources of water should be avoided.
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Affiliation(s)
- Richard G Lindsay
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia.
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Wekerle M, Engel J, Walochnik J. Anti-Acanthamoeba disinfection: hands, surfaces and wounds. Int J Antimicrob Agents 2020; 56:106122. [PMID: 32739477 DOI: 10.1016/j.ijantimicag.2020.106122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/16/2020] [Accepted: 07/23/2020] [Indexed: 12/19/2022]
Abstract
Acanthamoebae are facultative parasites causing rare but serious infections such as keratitis and encephalitis and are also known as vectors for several bacterial pathogens, including legionellae and pseudomonads. Acanthamoeba cysts are particularly resilient and enable the amoebae to withstand desiccation and to resist disinfection and therapy. While the search for new therapeutic options has been intensified in the past years, hand and surface disinfectants as well as topical antiseptics for preventing infections have not been studied in detail to date. The aim of this study was to screen well-known and commonly used antimicrobial products in various formulations and different concentrations for their efficacy against Acanthamoeba trophozoites and cysts, including aliphatic alcohols, quaternary ammonium compounds (QACs), peracetic acid (PAA), potassium peroxymonosulfate sulfate (PPMS) and octenidine dihydrochloride (OCT). Of all products tested, OCT and QACs showed the highest efficacy, totally eradicating both trophozoites and cysts within 1 min. The determined 50% effective concentration (EC50) for cysts was 0.196 mg/mL for OCT and 0.119 mg/mL for QACs after 1 min of exposure. PAA and PPMS showed reliable cysticidal efficacies only with prolonged incubation times of 30 min and 60 min, respectively. Aliphatic alcohols generally had limited efficacy, and only against trophozoites. In conclusion, OCT and QACs are potent actives against Acanthamoeba trophozoites and cysts at concentrations used in commercially available products, within contact times suitable for surface and hand disinfection as well as topical antisepsis.
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Affiliation(s)
- Maximilian Wekerle
- Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Kinderspitalgasse 15, 1090 Vienna, Austria
| | - Jan Engel
- Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Kinderspitalgasse 15, 1090 Vienna, Austria
| | - Julia Walochnik
- Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Kinderspitalgasse 15, 1090 Vienna, Austria.
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Miraflow, Soft Contact Lens Cleaner: Activity Against Acanthamoeba Spp. Eye Contact Lens 2015; 41:240-4. [PMID: 25603444 DOI: 10.1097/icl.0000000000000112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Miraflow is a cleaner for soft contact lens which contains 20% isopropyl alcohol. The purpose of this study was to determine the activity against Acanthamoeba trophozoites and cysts for Miraflow. In addition, to determine the activity of combined Miraflow and multipurpose solutions (MPSs) against Acanthamoeba cysts. METHODS Two simulated-use studies were conducted. The significance in the log reduction in the number of trophozoites and cysts of A. castellanii strains ATCC 50514 and ATCC 50370 or A. polyphaga ATCC 30461 after exposure to Miraflow alone was determined by the Spearman-Karber method. To examine the activity against Acanthamoeba of combined Miraflow and an MPS, the log reduction in the number of cysts after a 1-min exposure to Miraflow followed by a 4-hr exposure to MPS (ReNu fresh) was also determined. RESULTS Short-time exposure of 30 sec to Miraflow demonstrated activity against the Acanthamoeba trophozoites. However, a 1-min treatment was only relatively effective (1.1 log reduction) against the cysts of A. castellanii ATCC 50514, but no statistically significant reduction was observed for the cysts of the other 2 strains. The combined use with Miraflow and MPS demonstrated activity against the cysts, and a 3.0, 1.0, or 1.5 log reduction in the numbers was obtained for A. castellanii ATCC 50514, A. castellanii ATCC 50370, and A. polyphaga ATCC 30461, respectively. CONCLUSIONS Exposure to combined Miraflow and MPS resulted in reductions in the number of Acanthamoeba cysts.
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Tu EY, Shoff ME, Gao W, Joslin CE. Effect of low concentrations of benzalkonium chloride on acanthamoebal survival and its potential impact on empirical therapy of infectious keratitis. JAMA Ophthalmol 2013; 131:595-600. [PMID: 23519403 DOI: 10.1001/jamaophthalmol.2013.1644] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE The significant antiacanthamoebal effect of benzalkonium chloride, at or below concentrations used for preservation of common ophthalmic preparations, should be understood both when choosing empiric antibiotic therapy for infectious keratitis and when assessing the persistent rise in Acanthamoeba cases in the United States since 2003. OBJECTIVE To characterize the antiacanthamoebal efficacy of low concentrations of benzalkonium chloride (BAK) for drug preservation and therapeutic effect against Acanthamoeba. DESIGN Experimental study with a review of the literature. SETTING Laboratory. EXPOSURES A concentration of 10(4) trophozoites of 3 well-characterized clinical strains of Acanthamoeba were exposed at 0.5, 2.0, 3.5, 5.0, and 6.5 hours to BAK (0.001%, 0.002%, and 0.003%), moxifloxacin hydrochloride (0.5%), and moxifloxacin (0.5%) + BAK (0.001% and 0.003%) with hydrogen peroxide (3%) and amoeba saline controls. MAIN OUTCOMES AND MEASURES Amoeba survival was calculated using the most probable number method recorded as log kill values. The relationship of BAK concentration and exposure time as well as the relative effect of BAK and moxifloxacin on acanthamoebal survival were analyzed. RESULTS Amoebicidal activity of BAK is both time dependent and concentration dependent in pooled and strain-stratified analyses (P < .001). Moxifloxacin demonstrated no significant independent inhibitory effect or additive effect to BAK efficacy on acanthamoebal survival. The profound antiacanthamoebal effect of BAK, 0.003%, was similar to that of hydrogen peroxide for certain strains. CONCLUSIONS AND RELEVANCE Low concentrations of BAK, previously demonstrated to concentrate and persist in ocular surface epithelium, exhibit significant antiacanthamoebal activity in vitro at or below concentrations found in commercially available ophthalmic anti-infectives. The unexplained persistence of the Acanthamoeba keratitis outbreak in the United States, clusters abroad, and clinical studies reporting resolution or modification of Acanthamoeba keratitis without specific antiacanthamoebal therapy suggests that other contributing factors should be considered, including changes in the formulations used for empirical therapy of presumed infectious keratitis occurring in the same period.
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Affiliation(s)
- Elmer Y Tu
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA.
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Kobayashi T, Gibbon L, Mito T, Shiraishi A, Uno T, Ohashi Y. Efficacy of commercial soft contact lens disinfectant solutions against Acanthamoeba. Jpn J Ophthalmol 2011; 55:547-557. [DOI: 10.1007/s10384-011-0062-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Accepted: 04/19/2011] [Indexed: 10/18/2022]
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Thomas V, McDonnell G, Denyer SP, Maillard JY. Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality. FEMS Microbiol Rev 2010; 34:231-59. [DOI: 10.1111/j.1574-6976.2009.00190.x] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Abstract
PURPOSE To report bilateral Acanthamoeba keratitis after wearing an overnight reverse geometric contact lens for 5 days. METHODS Case report and review of the medical literature RESULTS A 22-year-old woman developed bilateral corneal ulcers during orthokeratology. A slit-lamp examination showed round epithelial abrasion, radial infiltration, and disciform keratitis in both corneas. Visual acuity OD was hand motion and OS was counting fingers. Bilateral Acanthamoeba keratitis was diagnosed by culture by using non-nutrient agar overlaid with viable Escherichia coli. Small, round, and double-walled cysts were observed in non-nutrient agar under an inverted phase contrast microscope. Topical 0.02% polyhexamethylene biguanide, Cravit (0.5% levofloxacin), and Tobra (0.5% tobramycin) were administered. After 1 month of treatment, the corneal ulcer had healed, and the patient's best-corrected visual acuity was 20/100 OD and 20/25 OS. CONCLUSIONS Acanthamoeba keratitis can simultaneously affect both eyes during overnight orthokeratology.
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Acanthamoeba: a review of its potential to cause keratitis, current lens care solution disinfection standards and methodologies, and strategies to reduce patient risk. Eye Contact Lens 2009; 34:247-53. [PMID: 18779663 DOI: 10.1097/icl.0b013e31817e7d83] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The recent outbreaks of Acanthamoeba keratitis (AK), a rare but serious infection of the cornea, has increased the attention on the pathology of the organism and safety standards as they relate to soft contact lens (SCL) disinfection and solution formulations. OBJECTIVE To review the pathologic potential of Acanthamoeba to produce keratitis in patients at risk, discuss the complex issues involved in Acanthamoeba SCL disinfection efficacy standards and testing methods, and present strategies for patients as well as governmental agencies to reduce the risk for future outbreaks of this organism. METHODS Studies that investigated the pathology and occurrence of AK and the various methods for testing SCL disinfection products for efficacy against Acanthamoeba were reviewed and the results were summarized. RESULTS.: Acanthamoeba is a ubiquitous organism in nature and has pathogenic and nonpathogenic strains. Trophozoites--not cysts--bind to specific mannosylated proteins on the corneal surface abraded by SCL wear. These bound trophozoites produce a cytotoxic serine protease enzyme that destroys corneal integrity and provides the mechanism for Acanthamoeba to produce keratitis. To date, nowhere in the world are Acanthamoeba challenges included in product approval of SCL disinfection products. Nonstandardized microbiologic methods for SCL disinfection efficacy against Acanthamoeba continue to produce highly variable data from study to study. There are no detailed and standardized methods as yet for trophozoite cell culture, trophozoite-to-cyst conversion, product challenge with amoeba, neutralization of the test sample's antimicrobial activity, and accurate quantification of viable survivor cells. CONCLUSIONS Reducing the incidence of AK is multifaceted and includes education of SCL wearers in the hygienic wear and care of their lenses, implementation of standardized and rigorous SCL solution disinfection requirements, and can also include improvements in the antimicrobial quality of municipal water supplies.
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Hiti K, Walochnik J, Maria Haller-Schober E, Faschinger C, Aspöck H. Efficacy of contact lens storage solutions against different acanthamoeba strains. Cornea 2006; 25:423-7. [PMID: 16670479 DOI: 10.1097/01.ico.0000214204.22200.7f] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE This study was undertaken in order to determine the susceptibility of acanthamoebae to various contact lens disinfecting systems, with respect to type of disinfectant and exposure time. METHODS Ten contact lens solutions, including one new system, were tested for their effectivities against cysts of three Acanthamoeba strains. Of main interest was an incubation time of 8 hours (overnight disinfection) and cyst quantities of 10 and 10, respectively. RESULTS Boston Advance (polyaminopropyl biguanide 0.0005%, chlorhexidine 0.003%) for the storage of rigid gas permeable contact lenses destroyed the cysts of all strains at either concentration within one hour of exposure. Meni Care Plus (polyhexamethylene biguanide 0.0005%) also destroyed 10 cysts of all strains, however, 10 cysts only of two strains within one hour; after an exposure time of 8 hours all cysts were killed. The disinfecting solutions for soft contact lenses did not kill 10 cysts of either strain after 8 hours of incubation time. CONCLUSION Two of the tested contact lens solutions (the ones for rigid gas permeable lenses) destroyed the cysts of all strains. One of these, containing a combination of two amoebicidal ingredients even after only one hour of exposure time.
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Affiliation(s)
- Klaus Hiti
- Department of Ophthalmology, University of Graz, Austria
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Hiti K, Walochnik J, Faschinger C, Haller-Schober EM, Aspöck H. One- and two-step hydrogen peroxide contact lens disinfection solutions against Acanthamoeba: How effective are they? Eye (Lond) 2004; 19:1301-5. [PMID: 15543174 DOI: 10.1038/sj.eye.6701752] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Effective contact lens disinfection solutions are important to keep the storage case free of acanthamoebae and thus prevent an infection of the eye. The aim of our study was to evaluate the effectivity of two new one-step hydrogen peroxide disinfecting solutions against Acanthamoeba spp. and compare it to the effectivity of other commercially available systems. METHODS Nine one-step 3% hydrogen peroxide systems including the new systems Silver Sept (platinum and silver disk for intensifying disinfection) and Blue Vision (newly composed catalytic tablet) and 2 two-step systems (0.6 and 3.0% H(2)O(2)) were tested for their effectivity against cysts of two Acanthamoeba keratitis isolates at different concentrations. RESULTS After a soaking time of 8 h (overnight soaking of contact lenses) the 2 two-step systems completely destroyed the cysts of both Acanthamoeba strains, even at the highest concentration of cysts tested. The nine tested one-step systems showed weaker effects. The new Blue Vision system was able to eradicate the cysts of one strain at the low concentration of cysts. CONCLUSIONS One-step hydrogen peroxide systems do not have sufficient effects on Acanthamoeba cysts and therefore may not protect the contact lens user from a possible infection of the eye. Further development of tablets like the ones used in the Blue Vision system may result in better cysticidal effects for one-step systems.
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Affiliation(s)
- K Hiti
- 1Department of Ophthalmology, University of Graz, Austria
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Hughes R, Heaselgrave W, Kilvington S. Acanthamoeba polyphaga strain age and method of cyst production influence the observed efficacy of therapeutic agents and contact lens disinfectants. Antimicrob Agents Chemother 2004; 47:3080-4. [PMID: 14506012 PMCID: PMC201123 DOI: 10.1128/aac.47.10.3080-3084.2003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effects of age in culture and the type of medium used for induction of Acanthamoeba polyphaga (Ros) cysts on susceptibilities to polyhexamethylene biguanide (PHMB; 3 micro g/ml), chlorhexidine digluconate (30 micro g/ml), myristamidopropyl dimethylamine (20 micro g/ml), H(2)O(2) (3%), and two multipurpose contact lens solutions (MPS-1 and MPS-2, based on 1 micro g of PHMB per ml) were examined. Strain Ros-02 was cryopreserved on isolation in 1991, while strain Ros-91 had been in continuous axenic culture. Significant differences in susceptibilities to the disinfectants were found depending on the medium used for cyst preparation and the age of the test strain, with Ros-02 generally being more resistant. For example, the killing of Ros-91 cysts produced from an axenic culture of trophozoites in the presence of 50 mM MgCl(2) by MPS-2 was 4 logs, but the killing of Ros-02 by MPS-2 was only 2 logs (P < 0.05) and killing of both strains with cysts obtained from monoxenic cultures with Escherichia coli was only 1 log (P < 0.001). Assays repeated with different batches of the various cyst types gave consistent results. A batch of Ros-91 cysts stored at 4 degrees C and tested over an 8-week period with MPS-1 showed progressively increasing susceptibility to disinfection, although there was no loss of viability during storage (P < 0.01). These observations have important implications for the standardization and interpretation of Acanthamoeba disinfectant and therapeutic agent testing.
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Affiliation(s)
- Reanne Hughes
- Department of Microbiology and Immunology, University of Leicester, Leicester LE1 9HN, United Kingdom.
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Affiliation(s)
- A Pinna
- Institute of Ophthalmology, University of Sassari, Viale San Pietro 43A, 07100 Sassari, Italy;
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Hiti K, Walochnik J, Haller-Schober EM, Faschinger C, Aspöck H. Viability of Acanthamoeba after exposure to a multipurpose disinfecting contact lens solution and two hydrogen peroxide systems. Br J Ophthalmol 2002; 86:144-6. [PMID: 11815336 PMCID: PMC1771011 DOI: 10.1136/bjo.86.2.144] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIM Contact lens cases contaminated with Acanthamoeba are a major risk factor for an infection of the eye. In this study the anti-Acanthamoeba activity of three different contact lens storage solutions was tested. METHODS A new multipurpose contact lens storage solution (Meni Care Plus) and a two step (Titmus H(2)O(2)) and one step (Oxysept Comfort) hydrogen peroxide system were tested for their effects on trophozoites and cysts of three different Acanthamoeba species: A castellanii, A hatchetti, and A lenticulata. RESULTS After a soaking time of 8 hours (overnight soaking of contact lenses) the Titmus H(2)O(2) 0.6% solution showed very good amoebicidal effects, while Oxysept Comfort 3% H(2)O(2) could not effectively destroy the cysts of any of the three tested species. Viable cysts of the species A lenticulata and A hatchetti were still present after exposure to Meni Care Plus (0.0005% PHMB) for 8 hours. CONCLUSION Not all of the three tested contact lens storage solutions have sufficient amoebicidal effects. The two step peroxide system Titmus H(2)O(2) is a very effective disinfectant contact lens solution in order to avoid a possible Acanthamoeba infection of the eye.
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Affiliation(s)
- K Hiti
- Department of Ophthalmology, University of Graz, Austria
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Hughes R, Kilvington S. Comparison of hydrogen peroxide contact lens disinfection systems and solutions against Acanthamoeba polyphaga. Antimicrob Agents Chemother 2001; 45:2038-43. [PMID: 11408220 PMCID: PMC90597 DOI: 10.1128/aac.45.7.2038-2043.2001] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acanthamoeba is a free-living amoeba causing a potentially blinding infection of the cornea. Contact lens wearers are most at risk and account for some 95% of cases. Hydrogen peroxide is used for contact lens disinfection due to its broad antimicrobial activity. Lenses must be neutralized before use to avoid pronounced stinging and possible corneal damage. Neutralization is achieved by adding a catalyst during the disinfection process (one-step) or afterwards (two-step). Here, the activities of commercial peroxide systems and individual solutions against trophozoites and cysts of Acanthamoeba polyphaga were compared. All disinfection systems were active against trophozoites, giving a > or = 3-log (99.9%) kill within 1 h. Of the four one-step systems, only one showed some cysticidal activity, giving a 1.28 +/- 0.41-log reduction. Both two-step systems were cysticidal, giving a > or = 3-log kill at 4 h. All system peroxide solutions were cysticidal, giving a > or = 3-log kill by 4 to 6 h. Variation in the cysticidal rate was observed with two solutions that gave a 1.8- to 2.1-log kill at 4 h compared with 3.0 to 4.0 for the rest (P < 0.05). No cysticidal activity was found with the peroxigen sodium perborate or the contact lens protein remover subtilisin A. Two-step systems are cysticidal providing contact times of at least 4 h are employed. Variation in cyst killing occurs between peroxide solutions, possibly due to formulation differences. One-step systems are less effective against Acanthamoeba cysts due to rapid peroxide neutralization. The cysticidal activity of one-step systems could be improved if neutralization rates were retarded.
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Affiliation(s)
- R Hughes
- Department of Microbiology and Immunology, University of Leicester, Leicester LE1 9HN, United Kingdom
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Dini LA, Cockinos C, Frean JA, Niszl IA, Markus MB. Unusual case of Acanthamoeba polyphaga and Pseudomonas aeruginosa keratitis in a contact lens wearer from Gauteng, South Africa. J Clin Microbiol 2000; 38:826-9. [PMID: 10655392 PMCID: PMC86214 DOI: 10.1128/jcm.38.2.826-829.2000] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/1999] [Accepted: 11/19/1999] [Indexed: 11/20/2022] Open
Abstract
Acanthamoeba species can cause a chronic, progressive ulcerative keratitis of the eye which is not responsive to the usual antimicrobial therapy and is frequently mistaken for stromal herpes keratitis. An unusual case of coinfection with Acanthamoeba polyphaga and Pseudomonas aeruginosa as causes of corneal keratitis in a contact lens wearer from Gauteng, South Africa, is reported. These two pathogens have previously been assumed to be selectively exclusive. Cysts of the isolated acanthameba tolerated an incubation temperature of 40 degrees C, indicating a pathogenic species. This case highlights the importance of culture methods in the diagnosis of corneal infection and the choice of treatment regimen. The patient's history of careless contact lens-disinfecting habits emphasizes the need to adhere strictly to recommended methods of contact lens care.
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Affiliation(s)
- L A Dini
- Department of Clinical Microbiology and Infectious Diseases, South African Institute for Medical Research and University of the Witwatersrand, University of the Witwatersrand, Johannesburg, South Africa.
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Hargrave SL, McCulley JP, Husseini Z. Results of a trial of combined propamidine isethionate and neomycin therapy for Acanthamoeba keratitis. Brolene Study Group. Ophthalmology 1999; 106:952-7. [PMID: 10328395 DOI: 10.1016/s0161-6420(99)00515-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
PURPOSE To characterize patients with Acanthamoeba keratitis and to evaluate the safety and efficacy of propamidine isethionate 0.1% ophthalmic solution (Brolene) when administered concomitantly with neomycin-polymyxin B-gramicidin ophthalmic solution (Neotricin) in the treatment of Acanthamoeba keratitis. DESIGN Prospective, noncomparative case series. METHODS The authors report the clinical characteristics and outcomes of patients who entered this multicentered, open-label, clinical trial. Eighty-three patients with Acanthamoeba keratitis representing 87 infected eyes entered the trial. RESULTS Sixty (69%) of the 87 eyes enrolled had data analyzed for treatment efficacy and safety. Of these 60 eyes, 50 (83%) experienced treatment success. Thirty (60%) patients successfully treated adhered to treatment protocol guidelines. Patients who broke protocol had disease exacerbation during the maintenance therapy phase. The only eyes lost/enucleated were 7 of 17 in which penetrating keratoplasty was performed before eradication of the infectious agent. CONCLUSION Propamidine isethionate and neomycin are an effective treatment for Acanthamoeba keratitis. Penetrating keratoplasty should be performed only for visual rehabilitation and not to "debulk" an active infection. The authors advocate treating patients with topical medications, mainly Brolene, until all organisms are eradicated. There should be no signs of infection for at least 3 months in the patients not receiving antiamebic medications before penetrating keratoplasty is performed.
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Affiliation(s)
- S L Hargrave
- Department of Ophthalmology, The University of Texas Southwestern Medical Center at Dallas, 75235-9057, USA
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Abstract
Acanthamoeba species are an important cause of microbial keratitis that may cause severe ocular inflammation and visual loss. The first cases were recognized in 1973, but the disease remained very rare until the 1980s, when an increase in incidence mainly associated with contact lens wear was reported. There is an increased risk when contact lens rinsing and soaking solutions are prepared with nonsterile water and salt tablets. The clinical picture is often characterized by severe pain with an early superficial keratitis that is often treated as herpes simplex infection. Subsequently a characteristic radial perineural infiltration may be seen, and ring infiltration is common. Limbitis and scleritis are frequent. Laboratory diagnosis is primarily by culture of epithelial samples inoculated onto agar plates spread with bacteria. Direct microscopy of samples using stains for the cyst wall or immunostaining may also be employed. A variety of topically applied therapeutic agents are thought to be effective, including propamidine isethionate, clotrimazole, polyhexamethylene biguanide, and chlorhexidine. Various combinations of these and other agents have been employed, often resulting in medical cure, especially if treatment is commenced early in the course of the disease. Penetrating keratoplasty is preferably avoided in inflamed eyes, but may be necessary in severe cases to preserve the globe or, when the infection has resolved, to restore corneal clarity for optical reasons.
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Khunkitti W, Lloyd D, Furr JR, Russell AD. Aspects of the mechanisms of action of biguanides on trophozoites and cysts of Acanthamoeba castellanii. J Appl Microbiol 1997; 82:107-14. [PMID: 9147866 DOI: 10.1111/j.1365-2672.1997.tb03304.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A non-radioactive method was used to investigate the uptake by Acanthamoeba castellanii of chlorhexidine diacetate (CHA) and polyhexamethylene biguanide (PHMD). Based on the Giles et al. (1974) hypothesis, the uptake of CHA by trophozoites appeared to be of the L3 pattern whereas that of cysts was C2. Unlike CHA, trophozoites took up PHMB with an L2 pattern at low concentrations followed by a C-type pattern at higher concentrations, the uptake by cysts was found to be of the C2 pattern with a plateau effect at high concentrations. A diphasic leakage effect was found in trophozoites whereas a relatively low peak of maximal leakage occurred from cysts treated with high biocide concentrations. The amount of pentose release depended on the formulation ingredients. No correlation between pentose leakage and trophozoicidal or cysticidal activity was found.
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Affiliation(s)
- W Khunkitti
- Welsh School of Pharmacy and School of Pure and Applied Biology, University of Wales, Cardiff, UK
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22
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Jones L, Jones D, Houlford M. Clinical comparison of three polyhexanide-preserved multi-purpose contact lens solutions. Cont Lens Anterior Eye 1997; 20:23-30. [PMID: 16303344 DOI: 10.1016/s1367-0484(97)80032-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/1996] [Revised: 11/18/1996] [Indexed: 11/23/2022]
Abstract
This study investigated the clinical differences between three commercially available polyhexanide (PHMB) preserved disinfection systems containing varying percentages of PHMB, when used with FDA group II and group IV disposable contact lenses. After 1 month of wear the product with the highest concentration of PHMB ('All-in-One') was graded as being less comfortable on insertion (P<0.003), had lower overall satisfaction (P<0.05) when compared with the other two products. Corneal staining was also significantly higher with this product after both 14 days (P<0.001 with group II and P<0.02 with group IV) and 28 days (P<0.00001 with group II and P<0.03 ith group IV).
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23
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Abstract
The contact lens industry has grown rapidly over the past four decades due to the wide-spread demands of the American population for a convenient alternative to spectacle wear for the correction of myopia. Unfortunately, many people who wear contact lenses are not aware of the potential risks associated with them, and consumer education about lens care has not been adequate. This article reviews the role of disinfection in contact lens wear, summarizes the current available contact lens disinfection systems, and provides recommendations for safe contact lens use.
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Affiliation(s)
- S B Levey
- Cornea Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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24
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Khunkitti W, Lloyd D, Furr JR, Russell AD. The lethal effects of biguanides on cysts and trophozoites of Acanthamoeba castellanii. THE JOURNAL OF APPLIED BACTERIOLOGY 1996; 81:73-7. [PMID: 8675485 DOI: 10.1111/j.1365-2672.1996.tb03284.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The effects of a range of biocides on trophozoite and encysted forms of Acanthamoeba castellanii were investigated. Viable acanthamoebae were enumerated by a plaque assay technique. The cyst form of Acanthamoeba castellanii was more resistant to all biocides tested than the trophozoite form. Of the biocides tested, chlorhexidine diacetate (CHA) and polyhexamethylene biguanide (PHMB) were the most effective. Their lethal effects were time- and concentration-dependent. CHA was very effective when formulated in 0.1% EDTA combined with Tris buffer pH 7.8 whereas PHMB activity was reduced by 0.1% EDTA. Three per cent dimethylsulphoxide (DMSO) enhanced the activity of CHA but not of PHMB.
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Affiliation(s)
- W Khunkitti
- Welsh School of Pharmacy, University of Wales College of Cardiff, UK
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25
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Mathers WD, Sutphin JE, Folberg R, Meier PA, Wenzel RP, Elgin RG. Outbreak of keratitis presumed to be caused by Acanthamoeba. Am J Ophthalmol 1996; 121:129-42. [PMID: 8623882 DOI: 10.1016/s0002-9394(14)70577-x] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
PURPOSE A sharp increase of Acanthamoeba keratitis from two cases per year to 30 cases per year at our institution prompted this study to determine whether there was a change in the clinical characteristics, basic epidemiology, and outcome of this disease. METHODS We reviewed all cases of Acanthamoeba keratitis diagnosed at the University of Iowa Hospitals and Clinics from mid-1993 through 1994. RESULTS We screened 217 patients with keratitis by tandem scanning confocal microscopy and suspected Acanthamoeba in 51 patients. Diagnosis was confirmed by cytology in 43 patients (48 eyes). There were no positive cultures. Patients examined within four weeks of onset of symptoms were younger (mean age, 32.6 +/- 15.4 years) and wore contact lenses (11 of 18 patients), and infrequently herpes simplex keratitis (four of 18 patients) was diagnosed. Patients examined after four weeks were older (mean age, 54.0 +/- 19.5 years), infrequently wore contact lenses (six of 25 patients), and often had herpes simplex keratitis (12 of 25 patients). CONCLUSIONS Corneal examination with tandem scanning confocal microscopy was associated with a marked increase in the detection of Acanthamoeba, strongly suggesting that the disease is more prevalent than suspected. Acanthamoeba may account for many cases of clinically presumed herpes simplex keratitis, the leading cause of corneal blindness in the United States. Acanthamoeba should be considered in the differential diagnosis of any unexplained keratitis, even those of short duration.
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Affiliation(s)
- W D Mathers
- Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City 52242-1091, USA.
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26
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Zanetti S, Fiori PL, Pinna A, Usai S, Carta F, Fadda G. Susceptibility of Acanthamoeba castellanii to contact lens disinfecting solutions. Antimicrob Agents Chemother 1995; 39:1596-8. [PMID: 7492111 PMCID: PMC162788 DOI: 10.1128/aac.39.7.1596] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A corneal isolate of Acanthamoeba castellanii was exposed to commercial contact lens disinfecting solutions containing hydrogen peroxide, benzalkonium chloride, polyaminopropyl biguanide, polyquaternium 1, and chlorhexidine-thimerosal. The minimum trophozoite amebicidal concentration and exposure times required to kill trophozoites and cysts were determined. Solutions containing hydrogen peroxide or chlorhexidine-thimerosal were active against both trophozoites and cysts. The benzalkonium chloride-based solution was effective only against trophozoites. Solutions containing polyaminopropyl biguanide or polyquaternium 1 were completely ineffective. The need for adequate exposure times must be stressed.
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Affiliation(s)
- S Zanetti
- Institute of Microbiology and Virology, University of Sassari, Italy
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Vesaluoma M, Kalso S, Jokipii L, Warhurst D, Pönkä A, Tervo T. Microbiological quality in Finnish public swimming pools and whirlpools with special reference to free living amoebae: a risk factor for contact lens wearers? Br J Ophthalmol 1995; 79:178-81. [PMID: 7696241 PMCID: PMC505052 DOI: 10.1136/bjo.79.2.178] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To assess the possible risk of microbial keratitis associated with swimming or bathing in public pools, the microbiological quality as well as the presence of free living amoebae in 16 halogenated swimming pools and whirlpools, located in Helsinki, Finland, was determined. Five additional whirlpools situated in the ferries cruising from Finland to Sweden were included in the study. Other parameters investigated were the total bacterial count, identification of Pseudomonas aeruginosa and Staphylococcus aureus, measurement of free residual and combined chlorine, potassium permanganate index, urine, pH, and turbidity. Amoebae were detected in 41% of the pool water samples studied. Seven of 11 whirlpools and four of 10 swimming pools were shown to contain amoebae. An Acanthamoeba species was isolated from only one outdoor swimming pool; the other amoebae belonged to the genera Vexillifera, Flabellula, Hartmannella, and Rugipes. Although not a single verified case of Acanthamoeba keratitis has been found in Finland, the findings show that there is a theoretical risk of amoebic and bacterial keratitis associated with swimming or bathing in properly cleaned public pools. Consequently, we do not recommend swimming or bathing with contact lenses.
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Affiliation(s)
- M Vesaluoma
- Department of Ophthalmology, Helsinki University Central Hospital, Finland
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28
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Stewart GL, Shupe K, Kim I, Silvany RE, Alizadeh H, McCulley JP, Niederkorn JY. Antibody-dependent neutrophil-mediated killing of Acanthamoeba castellanii. Int J Parasitol 1994; 24:739-42. [PMID: 7928077 DOI: 10.1016/0020-7519(94)90129-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Neutrophils from naive rats lysed low numbers of Acanthamoeba castellanii in the presence of normal rat serum and significantly higher numbers of the parasite in the presence of serum from immunized rats. With normal rat serum, neutrophils from rats immunized with crude parasite extract or from naive rats killed similar percentages of A. castellanii. However, neutrophils from immunized rats killed a significantly greater percentage of parasites in the presence of serum from immunized rats than was seen with any other combination of serum and neutrophils. The addition of supernatant from cultures of concanavalin A-stimulated rat spleen cells to incubations of the parasite in the presence of neutrophils from naive or immunized rats and immune serum resulted in the highest levels of amoebolysis seen in this study. This study has shown that neutrophils from naive rats or from rats immunized with A. castellanii antigen display a very limited amoebolytic capability which is significantly augmented in the presence of serum from immunized rats and further boosted by the addition of supernatant from Con A-stimulated rat spleen cell cultures.
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Affiliation(s)
- G L Stewart
- Center for Parasitology, University of Texas at Arlington 76019
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29
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Kersley HJ. Acanthamoeba - Why now? Eye (Lond) 1993. [DOI: 10.1038/eye.1993.167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Saunders PP, Proctor EM, Rollins DF, Richards JS. Enhanced killing of Acanthamoeba cysts in vitro using dimethylsulfoxide. Ophthalmology 1992; 99:1197-200. [PMID: 1513571 DOI: 10.1016/s0161-6420(92)31823-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Acanthamoeba keratitis is difficult to treat and requires prolonged therapy despite the well-documented in vitro effectiveness of a variety of drugs. The authors propose that this may be due to the cysts formed by the organism in response to hostile conditions. Consequently, the study concentrates on increasing penetration of drugs effective against the parasite into the cysts using dimethylsulfoxide (DMSO). METHODS The organism is forced to encyst in vitro on solid media by nutrient deprivation. In the first set of experiments, serial dilutions of a standard treatment regimen are applied to the organisms, and these treated cysts are then subcultured onto nutrient-rich material and observed for growth. The experiments are then repeated with DMSO added to the serially diluted standards. In a second set of experiments, the effects of retreatment on a larger concentration of organisms is examined. RESULTS When applied to a cyst-only population of Acanthamoeba, none of three standard drugs, propamidine isethionate 0.1%, neomycin 1%, or miconazole 1%, was cysticidal. When combined with DMSO 30%, propamidine isethionate was clearly cysticidal even in low dilution. This was confirmed by the retreatment experiments using a larger, standardized cyst population. CONCLUSION The authors propose that DMSO is acting as a "carrier" for the propamidine isethionate and increases its penetration into the normally drug-resistant cyst form of the organism. Because DMSO has been used topically in the past and shown to be quite safe, this may be a viable new therapy for this difficult condition.
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Affiliation(s)
- P P Saunders
- Department of Ophthalmology, University of British Columbia, Vancouver, Canada
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