The potential pathogenicity of chlorhexidine-sensitive Acanthamoeba strains isolated from contact lens cases from asymptomatic individuals in Tenerife, Canary Islands, Spain

Pathogenic strains of the genus Acanthamoeba are causative agents of a serious sight-threatening infection of the eye known as Acanthamoeba keratitis. The prevalence of this infection has risen in the past 20 years, mainly due to the increase in number of contact lens wearers. In this study, the prevalence of Acanthamoeba in a risk group constituted by asymptomatic contact lens wearers from Tenerife, Canary Islands, Spain, was evaluated. Contact lenses and contact lens cases were analysed for the presence of Acanthamoeba isolates. The isolates' genotypes were also determined after rDNA sequencing. The pathogenic potential of the isolated strains was subsequently established using previously described molecular and biochemical assays, which allowed the selection of three strains with high pathogenic potential. Furthermore, the sensitivity of these isolates against two standard drugs, ciprofloxacin and chlorhexidine, was analysed. As the three selected strains were sensitive to chlorhexidine, its activity and IC50 were evaluated. Chlorhexidine was found to be active against these strains and the obtained IC50 values were compared to the concentrations of this drug present in contact lens maintenance solutions. It was observed that the measured IC50 was higher than the concentration found in these maintenance solutions. Therefore, the ineffectiveness of chlorhexidine-containing contact lens maintenance solutions against potentially pathogenic strains of Acanthamoeba is demonstrated in this study.

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Presence of Acanthamoeba in the ocular surface in a Spanish population of contact lens wearers

Acta Parasitologica ◽

10.1515/ap-2018-0045 ◽

2018 ◽

Vol 63 (2) ◽

pp. 393-396 ◽

Cited By ~ 2

Author(s):

Javier Rodríguez-Martín ◽

Pedro Rocha-Cabrera ◽

María Reyes-Batlle ◽

Atteneri López-Arencibia ◽

Ines Sifaoui ◽

...

Keyword(s):

Molecular Analysis ◽

Canary Islands ◽

Contact Lens ◽

Ocular Surface ◽

Poor Prognosis ◽

Contact Lenses ◽

Opportunistic Pathogens ◽

Causative Agents ◽

Axenic Conditions ◽

Healthy Contact

Abstract Pathogenic strains of Acanthamoeba are causative agents of a sight-threatening infection of the cornea known as Acanthamoeba keratitis (AK) which mainly affects contact lens wearers and it is commonly related to poor hygiene of contact lenses and their cases. Moreover, treatment of AK is complex due to the existence of a highly resistant cyst stage and if not diagnosed early has poor prognosis, leading to blindness and/or keratoplasty. Even though AK is increasing worldwide as well as awareness among patients and clinicians, it is still a poorly studied pathogen. Additionally, a remaining question to be answered is whether these opportunistic pathogens are present in the ocular surface of healthy contact lens wearers since they are the main group at risk.In order to carry out this study, sterile Schirmer strip tests were collected from a group of individuals all of them contact lens wearers who were attending a local ophthalmology clinic in Tenerife, Canary Islands, Spain. The collected samples (100 eyes of 50 patients) were cultured in 2% Non-Nutrient Agar (NNA) plates and positive plates (16) were then cultured in axenic conditions for further analyses. Molecular analysis classified all isolated strains belonged to Acanthamoeba genotype T4 and osmotolerance and thermotolerance assays revealed that all strains were potentially pathogenic. In conclusion, the ocular surface of contact lens wearers included in this study was colonized by potentially pathogenic strains of Acanthamoeba and should be considered as a risk for AK infection in this region and worldwide.

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Molecular Identification of Pathogenic Free-Living Amoeba from Household Biofilm Samples in Iran: A Risk Factor for Acanthamoeba Keratitis

Microorganisms ◽

10.3390/microorganisms9102098 ◽

2021 ◽

Vol 9 (10) ◽

pp. 2098

Author(s):

Maryam Norouzi ◽

Reza Saberi ◽

Maryam Niyyati ◽

Jacob Lorenzo-Morales ◽

Hamed Mirjalali ◽

...

Keyword(s):

Contact Lenses ◽

Opportunistic Infections ◽

Acanthamoeba Keratitis ◽

Free Living ◽

Pathogenic Potential ◽

Ability Test ◽

Soft Contact Lenses ◽

Increased Risk ◽

Free Living Amoeba ◽

Causative Agents

Free-living amoeba (FLA) are ubiquitously distributed in the environment. However, they are also the causative agents of opportunistic infections in humans and other animals. A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. Moreover, FLA have been detected in various biofilms around the world. Therefore, the present study aimed to check for presence of FLA in samples from household biofilms in Iran and to characterize them at the molecular level. A total of 69 biofilm samples collected from showerheads, kitchen areas, and bathroom sinks were analyzed. Positive samples for FLA were characterized at the morphological and molecular levels. Furthermore, the results of morphology analysis indicated that 26.08% (18/69) of biofilm samples were positive for Acanthamoeba spp., Vermamoeba genus, and Vahlkampfiids. According to sequence analysis, five strains of Acanthamoeba isolates related to the T4 genotype and two strains belonged to the T2 genotype. In addition, the pathogenic potential of Acanthamoeba-positive isolates was conducted using the tolerance ability test. The results of BLASTn of Vermamoeba sequences were similar to what was expected for Vermamoeba vermiformis. The above-mentioned reasons revealed that the relative high contamination of household biofilm samples with FLA may pose a risk for people using soft contact lenses and for patients with traumatic cataract. Our finding proposes that filtration should be performed in shower heads and indicates the need to monitor people at increased risk of Acanthamoeba keratitis.

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Keeping an Eye on Contact Lenses: Safety, Options Shape Contact Lens Decisions

PsycEXTRA Dataset ◽

10.1037/e543682006-003 ◽

1998 ◽

Author(s):

Dixie Farley

Keyword(s):

Contact Lens ◽

Contact Lenses

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Optimum Infinite is a new era of oxygen permeability material for contact lenses

The Eye ◽

10.33791/2222-4408-2020-1-44-46 ◽

2020 ◽

Vol 22 (129) ◽

pp. 44-46

Author(s):

Mark Eddleston

Keyword(s):

Contact Lens ◽

Oxygen Permeability ◽

Contact Lenses ◽

New Era ◽

Lens Material ◽

Insight Into

Optimum Infinite is a new GP contact lens material, with an oxygen permeability of 180 barrer and was launched by Contamac at the GSLS 2019. This article provides an insight into the development and characteristics of this breakthrough material.

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