Trabajo presentado en la IV International Conference on Antimicrobial Research ICAR, celebrada en Torremolinos (España) del 29 de junio al 1 de julio de 2016.
The free-living amoebae are widely distributed in nature, with many species isolated from earth, air, treated water for consumption, sea water or lake of hot springs. Acanthamoeba is a protozoan of worldwide distribution and although included in the group of free-living amoebae. In humans, some of them can produce different pathologies; mainly keratitis, Granulomatous amoebic encephalitis and skin ulcers. Within its life cycle two distinct forms appear: trophozoites, which are mobile, and cysts, which are uninucleated, circular and immobile and constitute the form of parasite resistance. Trophozoites appear under the amoeboid form, with reproductive capacity. Despite its clinical importance, there is no vaccine available. Current therapeutic approaches for the prevention and treatment of infections are limited or inadequate. We have tested cathelicidins from mammals, reptile and birds from avian, aquatic andterrestrial environments. The antimicrobial activity of these peptides has been tested against trophozoites from two Acanthamoeba species: A. castellanii Neff genotype T4 (ATCC: 30010) and a pathogenic species of genotype T3, isolated from a patient suffering of keratitis For the antimicrobial assay, we used a modification of the method of sulphorhodamine (SRB) usually described to measure activity of peptides against human tumoral cell lines. This method is based on the ability of sulphorhodamineto stain the basic amino acids of cellular proteins remaining in the plates at the end of the assay. Some of the derived peptides exhibited significant antimicrobial activity at micromolar concentrations. Haemolytic activity of peptides was also tested using rabbit erythrocytes. Further studies are underway to determine the underlying mechanism of cell death induced by these antimicrobial peptides. We hope that our preliminary investigation with these novel peptides could provide novel treatment opportunities against Acanthamoeba pathologies.