Experimental infection of T4 Acanthamoeba genotype determines the pathogenic potential
Daniella de Sousa Mendes Moreira Alves1, Aline Silva Moraes2, Luciano Moreira Alves3
1Instituto de Patologia Tropical e Saúde Pública (IPTSP), Universidade Federal de Goiás, Rua 235, s/n, Setor Universitário, Goiânia, GO, 74650-050, Brazil. alveslm@gmail.com.
Abstract:
T4 is the Acanthamoeba genotype most related to cases of granulomatous amoebic encephalitis (GAE) in immunocompromised patients and of keratitis in contact lens wearers. The determination of the pathogenic potential of Acanthamoeba clinical and environmental isolates using experimental models is extremely important to elucidate the capacity of free-living organisms to establish and cause disease in hosts. The aim of this study was to compare and evaluate the histopathology and culture between two different routes of experimental infection of T4 Acanthamoeba isolated from environmental and clinical source in mice (intracranial and intraperitoneal). Swiss isogenic healthy mice were inoculated with 10(4) trophozoites by intracranial (IC) and intraperitoneal (IP) routes and observed during 21 days. The brains from animals inoculated by the IC route were collected and from the animals of the IP inoculation group, the brains, livers, kidneys, spleens, and lungs were removed. The organs were prepared and appropriately divided to be evaluated with histopathology and culture. There was no significant difference between the inoculation routes in terms of isolates recovery (χ(2) = 0.09; p = 0.76). In the IC group, isolate recovery rate was significantly higher in histopathology than the one achieved by culture (χ(2) = 6.45; p < 0.01). Experimental infection revealed that all isolates inoculated could be considered invasive because it was possible to recover evolutive forms of Acanthamoeba in both routes. This work represents the first in vivo pathogenicity assay of primary isolation source in Central region of Brazil showing in vivo pathogenicity and hematogenous spread capacity of these protozoa, improving the knowledge on free-living amoebae isolates.
Insights
This study investigated Acanthamoeba T4 genotype pathogenicity in mice using intracranial and intraperitoneal infections. Both routes demonstrated Acanthamoeba invasiveness, with histopathology proving more effective for isolate recovery in brain infections.
Area of Science:
- Medical Microbiology
- Parasitology
- Infectious Diseases
Background:
- Acanthamoeba genotype T4 is linked to severe human diseases like granulomatous amoebic encephalitis (GAE) and keratitis.
- Understanding the pathogenic potential of Acanthamoeba isolates is crucial for disease prevention and treatment strategies.
- Experimental models are essential for evaluating the ability of free-living amoebae to cause infection in hosts.
Purpose of the Study:
- To compare the efficacy of histopathology and culture in detecting Acanthamoeba T4 infection.
- To evaluate and compare the pathogenicity of Acanthamoeba T4 isolates from environmental and clinical sources.
- To assess two different experimental infection routes (intracranial and intraperitoneal) in mice.
Main Methods:
- Swiss mice were inoculated with 10(4) Acanthamoeba T4 trophozoites via intracranial (IC) and intraperitoneal (IP) routes.
- Animals were observed for 21 days post-inoculation.
- Brains (IC group) and multiple organs (IP group: brains, livers, kidneys, spleens, lungs) were collected for histopathology and culture analysis.
Main Results:
- No significant difference was observed in Acanthamoeba isolate recovery rates between the IC and IP inoculation routes.
- Histopathology yielded a significantly higher isolate recovery rate compared to culture in the IC group (p < 0.01).
- All inoculated Acanthamoeba isolates were deemed invasive, with recoverable forms found in both infection routes.
Conclusions:
- Both intracranial and intraperitoneal inoculation routes effectively demonstrate the invasiveness of Acanthamoeba T4.
- Histopathology is a more sensitive method than culture for detecting Acanthamoeba in brain tissue following IC infection.
- This study provides the first in vivo pathogenicity data for Acanthamoeba T4 isolates from Brazil's Central region, highlighting their invasive potential and capacity for hematogenous spread.
