Effects of Multipurpose Solutions on the Viability and Encystment of Acanthamoeba Determined by Flow Cytometry

Imayasu, Masaki; Tchedre, Kissaou; Cavanagh, Harrison D

doi:10.1097/icl.0b013e31828af147

Cited by 10 publications

(5 citation statements)

References 27 publications

(39 reference statements)

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“…In this endeavor, we have analyzed the antimicrobial activity of a wider range of marketed CLC products than other recent method advancement attempts [12,14]. Further, this novel method development examines more individual strains of Acanthamoeba within one body of work, which are the most common pathogens associated with AK and are strains that are well-established laboratory and clinical strains thoroughly described in the literature [20][21][22], which is more than other method development attempts [12,14,15,23,24].…”

Section: Discussionmentioning

confidence: 99%

“…Further, Trypan Blue staining methods depend solely upon a hemocytometer cell count, and thus, are less accurately quantified [30]. Additionally, it must be stated that staining methods that involve flow cytometry depend on cell permeability to dyes to facilitate accurate counting, which are difficult to accurately align with the use of flow and have failed to appropriately address trophozoite permeability in the presence of biocides [23,24,31]. Most importantly, to our knowledge, none of these methods can be or were directly compared to widely-reported testing methods to ensure an equal comparison, indicating a major flaw of method development so far.…”

Section: Discussionmentioning

confidence: 99%

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Evaluating Alternate Methods of Determining the Antimicrobial Efficacy of Contact Lens Care Products against Acanthamoeba Trophozoites

2021

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Acanthamoeba keratitis (AK) is a serious ocular infection caused by a ubiquitous free-living amoeba, Acanthamoeba. This infection often results in extensive corneal damage and blindness, and is notoriously difficult to cure. While Acanthamoeba is an abundant organism, AK is most associated with contact lens hygiene noncompliance and inadequate contact lens care (CLC) disinfection regimens. Thus, accurate and timely antimicrobial efficacy testing of CLC solutions is paramount. Published methods for antimicrobial efficacy testing of Acanthamoeba trophozoites requires 14 days for results. Presently, alternate and/or rapid methods for evaluating CLC products rarely demonstrate equivalent results compared to commonly-reported methods. Propidium iodide is a cellular stain that can only bind to cells with damaged outer membranes. We evaluated propidium iodide staining as an alternative method for determining the relative antimicrobial efficacy of 11 different CLC products against Acanthamoeba trophozoites. Following exposure to a CLC product, the fluorescence intensity of propidium iodide in an Acanthamoeba population demonstrated a strong correlation to the log reduction determined by established, growth-based Acanthamoeba testing used to evaluate the antimicrobial efficacy of CLC products. Thus, propidium iodide was found to be an effective rapid tool for determining cell death in Acanthamoeba trophozoites following exposure to CLC solutions.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Evaluating Alternate Methods of Determining the Antimicrobial Efficacy of Contact Lens Care Products against Acanthamoeba Trophozoites

2021

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“…As mentioned previously, in 2007 an outbreak of Acanthamoeba keratitis, was linked to use of Complete MoisturePlus (AMO, Santa Ana, CA). Laboratory investigations later revealed that a component of the solution, proplylene glycol, induced encystment of Acanthamoeba trophozoites, potentially rendering the organism more resistant to disinfection …”

Section: Epidemiology Of Acanthamoeba Keratitismentioning

confidence: 99%

“…Laboratory investigations later revealed that a component of the solution, proplylene glycol, induced encystment of Acanthamoeba trophozoites, potentially rendering the organism more resistant to disinfection. [109][110][111][112] Following the recall of Complete MoisturePlus, there was a drop in the number of cases in the US, however this decrease did not reach the low level prior to the product launch. 113 There seemed to be some residual increased risk that was not present in the early 2000s.…”

Section: Contact Lens Solutions and Their Usementioning

confidence: 99%

Strategies for the prevention of contact lens‐related Acanthamoeba keratitis: a review

Carnt

Stapleton

2015

Ophthalmic Physiologic Optic

100

129

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Purpose: Acanthamoeba keratitis is a severe, often sight threatening, corneal infection which in Western countries is predominantly seen in daily wear of contact lenses. This review aims to summarise the pathobiology and epidemiology of contact lens-related Acanthamoeba keratitis, and to present strategies for prevention, particularly with respect to modifiable risk factors in contact lens wear. Recent Findings: The virulence of Acanthamoeba and resistance to treatment in keratitis appears to be linked with the production of a low molecular weight pro-tease MIP133 by the organism, in response to binding to corneal epithelial cells through a mannose binding protein, and to the ability of the organism to convert from the trophozoite to the resistant cyst form. Recent epidemiological studies in contact lens relate disease have confirmed the link between solution topping up and Acanthamoeba keratitis and have reinforced the importance of avoidance of tap water, either as part of the care for the contact lens or storage case, handling lenses with wet hands or showering while wearing lenses. In the most recent analysis from the USA, there were no strong effects for solution type, water source or water disinfection process. Wearer age, lens wear time and history to appear to be linked with Acanthamoeba keratitis. Daily disposable contact lens use would be expected to reduce the prevalence of Acanthamoeba disease although this is unproven. Summary: While Acanthamoeba keratitis remains challenging to diagnose and manage, strategies to limit the disease severity in contact lens wearers should include attention to recently identified risk factors, particularly those related to water contact. Public health awareness measures, the use of daily disposable contact lenses, a better understanding of the contribution of the host immunity and the development of standardised methods for culture of amoeba and testing of contact lens care systems against Acanthamoeba in the licensing process may be of value. Alternative treatments for the future may include those which target the mannose binding protein or the genes which control conversion to the cyst form.

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“…AK is a sight-threatening condition, and outbreaks have been linked to specific contact lens solutions ( 3 ), hard water with lime scale ( 4 ), and biofilm contamination of domestic and recreational water ( 5 , 6 ). The expanding problem of algal bloom and nutrient pollution in Iowa waters might also be contributing to an increase in pathogenic Acanthamoeba species and the rising number of AK cases ( 6 ).…”

mentioning

confidence: 99%

Notes from the Field: Acanthamoeba Keratitis Cases — Iowa, 2002–2017

Scruggs¹,

Quist²,

Salinas³

et al. 2019

MMWR Morb. Mortal. Wkly. Rep.

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Effects of Multipurpose Solutions on the Viability and Encystment of Acanthamoeba Determined by Flow Cytometry

Cited by 10 publications

References 27 publications

Evaluating Alternate Methods of Determining the Antimicrobial Efficacy of Contact Lens Care Products against Acanthamoeba Trophozoites

Evaluating Alternate Methods of Determining the Antimicrobial Efficacy of Contact Lens Care Products against Acanthamoeba Trophozoites

Strategies for the prevention of contact lens‐related Acanthamoeba keratitis: a review

Notes from the Field: Acanthamoeba Keratitis Cases — Iowa, 2002–2017

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