Infection in a rat model reactivates attenuated virulence after long-term axenic culture of Acanthamoeba spp

Carolina De Marco Veríssimo,Vinícius José Maschio,Marilise Brittes Rott,Ana Paula Folmer Correa,Adriano Brandelli

doi:10.1590/0074-0276130099

Carolina De Marco Veríssimo, Vinícius José Maschio + Show 3 more

Open Access

https://doi.org/10.1590/0074-0276130099

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Abstract

Prolonged culturing of many microorganisms leads to the loss of virulence and a reduction of their infective capacity. However, little is known about the changes in the pathogenic strains of Acanthamoeba after long culture periods. Our study evaluated the effect of prolonged culturing on the invasiveness of different isolates of Acanthamoeba in an in vivo rat model. ATCC strains of Acanthamoeba, isolates from the environment and clinical cases were evaluated. The in vivo model was effective in establishing the infection and differentiating the pathogenicity of the isolates and re-isolates. The amoebae cultured in the laboratory for long periods were less virulent than those that were recently isolated, confirming the importance of passing Acanthamoeba strains in animal models.

Highlights

Acanthamoeba, a genus of free-living amoebae, is widely dispersed in the environment and can be found in natural water bodies, dust, air conditioners, swimming pools and hospitals (Marciano-Cabral & Cabral 2003, Caumo et al 2009, Magliano et al 2009, Carlesso et al 2010)
Acanthamoeba is the agent responsible for granulomatous amoebic encephalitis (GAE), which is a progressive infection of the central nervous system (CNS) that almost exclusively affects immunocompromised individuals
Acanthamoeba were found in the lungs and brain tissue of mice

Summary

Introduction

Acanthamoeba, a genus of free-living amoebae, is widely dispersed in the environment and can be found in natural water bodies, dust, air conditioners, swimming pools and hospitals (Marciano-Cabral & Cabral 2003, Caumo et al 2009, Magliano et al 2009, Carlesso et al 2010). Research on the pathogenic potential of Acanthamoeba is complicated by the changes induced by prolonged axenic laboratory culture, such as the downregulation of its virulence and encystment capacity and its altered sensitivity to drugs (Mazur & Hadas 1994, Hughes et al 2003, Koehsler et al 2008). These adaptations clearly affect studies on the pathogenic potential and drug susceptibility of Acanthamoeba and an effective method to maintain or reactivate the properties of freshly isolated amoebae is highly desirable. The present study evaluated the effect of the prolonged culturing of different isolates of Acanthamoeba on their invasiveness in a rat model

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