In Vitro Evaluation of Combined Commercialized Ophthalmic Solutions Against Acanthamoeba Strains.

Acanthamoeba is a free-living amoebae genus which is present worldwide in natural and artificial environments. These amoebae are clinically important as causative agents of diseases in humans and other animals such as a fatal encephalitis or a sight threatening Acanthamoeba keratitis (AK). Lately; studies have focused on the search of novel therapeutic options for AK but also to prevent infections. Furthermore; the evaluation of commercialized products seems to be an option for this case since not clinical assays would be required. Thus; we aimed to test the amoebicidal activity of different mixtures of two commercial ophthalmic solutions: Systane® Ultra; which has already shown anti-Acanthamoeba properties; and Naviblef® Daily Care. In addition, we tested their cytotoxic effect against murine macrophages. At the individual level; Naviblef® Daily Care showed to be the most active product against Acanthamoeba spp. Nevertheless; the combinations of Systane® Ultra and Naviblef® Daily Care; showed an improvement in the activity against trophozoites and cysts of Acanthamoeba castellanii Neff. Moreover; the concentration necessary to generate cytotoxic effect against murine macrophages (J774.1) was much higher than the required for the amoebicidal and cysticidal effect achieved in the most effective mixtures.

Isolation and Molecular Identification of Naegleria australiensis in Irrigation Water of Fuerteventura Island, Spain.

INTRODUCTION: Saline groundwater desalination has recently emerged as an alternative source of irrigation water in arid and semiarid regions due to the gradual reduction in the quantity and quality of conventional water resources for agricultural use. In Fuerteventura Island (Spain), an extremely arid territory in the European Union, brackish water desalination is one of the few available water sources for agricultural production. Very little research has been conducted on the microbiological quality of this water mainly used for irrigation of vegetable crops. Free-living amoebae (FLA) are widely distributed protozoa in the environment and have been isolated from many environmental sources such as dust, soil and water. Among the pathogenic genera included in this group, Acanthamoeba spp., Naegleria fowleri and Balamuthia mandrillaris have been reported to be causative agents of lethal encephalitis, disseminated infections and keratitis. Particularly, Naegleria fowleri is a pathogenic FLA species which causes primary amoebic meningoencephalitis (PAM). MATERIALS AND METHODS: In the present study, the presence of pathogenic FLA strains on desalinated brackish water samples for irrigation has been evaluated during 7 months. RESULTS: From the analysed samples, only one was positive for Naegleria australiensis. This is the first report of Naegleria spp. in desalinated brackish water for irrigation in Spain.

Isolation of thermotolerant Vermamoeba vermiformis strains from water sources in Lanzarote Island, Canary Islands, Spain.

In this study, twenty water samples were collected in the island of Lanzarote, Canary Islands, Spain in order to check for the presence of V. vermiformis strains in these samples. Water samples were cultured on 2% Non-Nutrient Agar (NNA) plates covered with a thin layer of heat killed E. coli and checked daily for the presence of Vermamoeba. After a week, V. vermiformis amoebae were observed in 2 of the 20 processed samples (10%) incubated at room temperature and 37°C. Molecular characterization was carried out by amplifying the 18S rDNA gene and DNA sequencing in order to confirm the identity of the isolated amoebic strains. To the best of our knowledge, this is the first report on the presence of FLA in environmental sources in Lanzarote Island and the first report of Vermamoeba vermiformis in water sources in this island. Furthermore, the two strains isolated in this study were collected in recreational areas with close contact with humans and thus awareness should be raised.

Isolation and Molecular Identification of Vermamoeba vermiformis Strains from Soil Sources in El Hierro Island, Canary Islands, Spain.

Free-living amoebae (FLA) are widely distributed protozoa in the environment and have been isolated from many sources such as dust, soil and water. Furthermore, some genera/species of FLA such as Naegleria fowleri, Balamuthia mandrillaris and Acanthamoeba spp. are also able to cause opportunistic infections in humans and other animals. More recently, FLA have been reported to be environmental carriers of pathogenic bacteria, fungi and viruses, and thus have gained further importance from the public health point of view. Among them, Acanthamoeba spp. and Vermamoeba vermiformis have been described in many occasions as the most common carriers of pathogens of high medical relevance such as Legionella pneumophila and Mycobacterium spp. In this study, 24 soil samples were collected from the island of El Hierro, Canary Islands, Spain, in order to check for the presence of V. vermiformis strains in these samples. Soil samples were cultured on 2 % non-nutrient agar plates covered with a thin layer of heat-killed E. coli and checked daily for the presence of Vermamoeba. After a week, V. vermiformis amoebae were observed in 5 of the 24 processed samples (20.8 %) incubated at room temperature and 37 °C. Molecular characterization was carried out by amplifying the 18S rDNA gene and DNA sequencing, confirming that the isolated strains belonged to Vermamoeba vermiformis species. The high percentage of V. vermiformis in the studied soil sources should raise awareness in the region since these amoebae are potential environmental carriers of pathogens of high medical relevance.

Acanthamoeba genotypes T2, T4, and T11 in soil sources from El Hierro island, Canary Islands, Spain.

The genus Acanthamoeba includes pathogenic strains which are causative agents of keratitis and encephalitis that often may end fatal in humans and other animals. In the present study, forty soil samples were collected in the island of El Hierro, Canary Islands, Spain, and checked for the presence of Acanthamoeba. Samples were cultivated onto 2 % non-nutrient agar plates seeded with a layer of heat killed Escherichia coli. Amplification by PCR and sequencing of the DF3 region of the 18S rDNA of Acanthamoeba was carried out in order to confirm morphological identification of the amoebae. Furthermore, Acanthamoeba spp. was isolated from 47.5 % of soil samples. Moreover, genotypes T2, T4, and T11 were identified in these samples. To the best of our knowledge, this is the first study to establish genotypes T2, T4, and T11 in soil sources from El Hierro island.