Experimental infection of T4 Acanthamoeba genotype determines the pathogenic potential

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.

Evaluating Alternate Methods of Determining the Antimicrobial Efficacy of Contact Lens Care Products against Acanthamoeba Trophozoites

“…In this endeavor, we have analyzed the antimicrobial activity of a wider range of marketed CLC products than other recent method advancement attempts [12,14]. Further, this novel method development examines more individual strains of Acanthamoeba within one body of work, which are the most common pathogens associated with AK and are strains that are well-established laboratory and clinical strains thoroughly described in the literature [20][21][22], which is more than other method development attempts [12,14,15,23,24].…”

Viability test exclusively is not adequate to evaluate the T4 Acanthamoeba keratitis’ treatment

“…25 Only the IP1S1 (swiming pool) isolate showed no reduction in cysts quantification after the treatment regimens (1h and 24h). The increase in cysts quantification in control group (1h) of 1P1S1 isolate could also be related to the resistance of this isolate previously described by our team as invasive 26 demonstrating the ability of its trophozoites to multiply from the initial inoculum, which would make it difficult to reduce the cysts concentration by drugs action. One of the risk factors for keratitis is the practice of swimming wearing contact lenses.…”

Schwann Cell Autophagy and Necrosis as Mechanisms of Cell Death by Acanthamoeba

“…The primary Acanthamoeba site of infection can be the respiratory tract, were amoebae reach the olfactory neuroepithelium, leading to interactions with the blood–brain barrier and, finally, CNS invasion [ 2 , 5 , 6 ]. Moreover, through in vivo experimental models, blood flow dissemination of amoebae inoculated in the peritoneum [ 7 ] or intranasal route of healthy [ 4 ] and diabetic mice [ 8 ] has been reported.…”