Naegleria fowleri causes a deadly disease called primary amoebic meningoencephalitis (PAM). Even though PAM is still considered a rare disease, the number of reported cases worldwide has been increasing each year. Among the factors to be considered for this, awareness about this disease, and also global warming, as these amoebae thrive in warm water bodies, seem to be the key factors. Until present, no fully effective drugs have been developed to treat PAM, and the current options are amphotericin B and miltefosine, which present side effects such as liver and kidney toxicity. Statins are able to inhibit the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, which is a key enzyme for the synthesis of ergosterol of the cell membrane of these amoebae. Therefore, the in vitro activity of a group of statins was tested in this study against two types of strains of Naegleria fowleri. The obtained results showed that fluvastatin was the most effective statin tested in this study and was able to eliminate these amoebae at concentrations of 0.179 ± 0.078 to 1.682 ± 0.775 µM depending on the tested strain of N. fowleri. Therefore, fluvastatin could be a potential novel therapeutic agent against this emerging pathogen.

Amoebae of the genus Acanthamoeba are ubiquitous protists that have been isolated from many sources such as soils, water and the air. They are responsible for infections including fatal encephalitis and a severe keratitis in humans. To date, there is no satisfactorily effective therapeutic agent against this pathogen and the infections it causes are exacerbated by the existence of a resistant cyst stage produced by this amoeba. As dry eye syndrome is a risk factor for Acanthamoeba keratitis, we aimed to evaluate the anti-Acanthamoeba activity of a variety of proprietary eye drops intended to treat dry eye syndrome. From the nine eye drop formulations tested, “Systane Ultra” was determined to be the most active against all tested Acanthamoeba strains. During our investigations into the mode of action of Systane Ultra, we discovered that it decreases mitochondrial membrane potential and ATP levels, induces chromatin condensation, and increases the permeability of the plasma-membrane.

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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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The main corneal infections reported worldwide are caused by bacteria and viruses but, recently, the number of Acanthamoeba keratitis (AK) cases has increased. Acanthamoeba genus is an opportunistic free living protozoa widely distributed in environmental and clinical sources, with two life-cycle stages: the trophozoite and the cyst. AK presents as primary symptoms eye redness, epithelial defects, photophobia and intense pain. An early diagnosis and an effective treatment are crucial to avoid blindness or eye removal but, so far, there is no established treatment to this corneal infection. Diverse research studies have reported the efficacy of commercialized eye drops and ophthalmic solutions against the two life cycle stages of Acanthamoeba strains, that usually present preservatives such as Propylene Glycol of Benzalkonium chloride (BAK). These compounds present toxic effects in corneal cells, favouring the inflammatory response in the so sensitive eye tissue. In the present work we have evaluated the efficacy of nine proprietary ophthalmic solutions with and without preservatives (ASDA Dry Eyes Eyedrops, Miren®, ODM5®, Ectodol®, Systane® Complete, Ocudox®, Matrix Ocular®, Alins® and Coqun®) against the two life cycle stages of three Acanthamoeba strains. Our work has demonstrated the high anti- Acanthamoeba activity of Matrix Ocular®, which induces the programmed cell death mechanisms in Acanthamoeba spp. trophozoites. The high efficacy and the absence of ocular toxic effects of Matrix Ocular®, evidences the use of the Arabinogalactan derivatives as a new source of anti-AK compounds.

Interest in periocular (eyelid and eyelashes margins) hygiene has attracted attention recently and a growing number of commercials eye cleanser and shampoos have been marketed. In the present study, a particular eye cleanser foam, Belcils® has been tested against trophozoites and cysts on the facultative pathogen Acanthamoeba . Viability was tested by the alamarBlue™ method and the foam was tested for the induction of programmed cell death in order to explore its mode of action. We found that a 1% solution of the foam eliminated both trophozoite and cyst stage of Acanthamoeba spp. After 90 min of incubation, Belcils® induced, DNA condensation, collapse in the mitochondrial membrane potential and reduction of the ATP level production in Acanthamoeba . We conclude that the foam destroys the cells by the induction of an apoptosis-like process. The current eye cleanser could be used as part of AK therapy protocol and as prevention from AK infections for contact lens users and post-ocular trauma patients.