Assessment of virulence factors of Acanthamoeba spp. isolates

• Grant number: 24/13589-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2024
• End date: September 30, 2025
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Denise de Freitas
• Grantee: João Lucas Benício Alves
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Acanthamoeba are aerobic, unicellular protozoa widely distributed in natural and artificial environments, such as soil, rivers, lakes, swimming pools and air conditioning systems. They can exist in a free or parasitic form, with trophozoites as the active form and cysts as the resistant form. The species are classified into three morphological groups based on cyst morphology and into 23 genotypes by 18S rDNA sequencing. Acanthamoeba, as an opportunistic agent, can cause infections such as keratitis and amoebic granulomatous encephalitis, especially in immunocompromised individuals. Pathogenicity is related to adhesion to the corneal epithelium, toxin production and resistance to immune factors and drugs. Studies have shown an association between phenotypic alterations and pathogenic characteristics of different isolates of this genus, which may be associated with greater severity of Acanthamoeba keratitis. For this reason, this study aims to evaluate the virulence of different Acanthamoeba isolates using parameters such as growth rate, encystment, osmotolerance, thermotolerance and cytopathic effect in cell culture, in order to characterize and associate these phenotypic changes with the pathogenesis of the different isolates, and thus better understand the pathophysiology of Acanthamoeba keratitis.