Parasit Acanthamoeba spp. Flashcards
is a ubiquitous, free-living
ameba that is the etiologic agent of AK and GAE
Acanthamoeba spp.
diseases caused by Acanthamoeba spp. (2)
Acanthamoeba keratitis and Granulomatous amebic encephalitis
Acanthamoeba is
characterized by an ________________ stage
with characteristic prominent “thorn-like”
appendages _______________________
active trophozoite, acanthopodia
Motile trophozoites of Acanthamoeba spp. feed on __________________________
gram negative bacteria, blue-green algae, or yeasts
Acanthamoeba spp. trophozoite reproduce by _________
Mitosis
Examples of naturally-occurring bacterial endosymbionts in Acanthamoeba
spp. (3)
o Legionella spp.
o mycobacteria,
o gram-negative bacilli such as E. coli
infective stage of the Acanthamoeba spp.
Trophozoite stage
Incubation period of PAM
2-15 days (Average 5 days)
What Acanthamoeba spp.
Associated with the
use of improperly disinfected soft contact
lenses, particularly those which are rinsed with
tap water or contaminated lens solution.
Acanthamoeba keratitis
GAE usually occurs
in _______________________ hosts
immunocompromised
most virulent Acanthamoeba spp; binds more firmly to host cell membrane surfaces
T4 genotype
Acanthamoeba spp. that are Usually more associated with ocular
infection and keratitis
A. castellani & A. polyphaga
Acanthamoeba spp. that are Usually more associated with Acanthamoeba
granulomatous encephalitis
A. culbertsoni
Acanthamoeba spp. incubation period from initial inoculation
is about ______
10 days
Virulence factors of Acanthamoeba spp. (3)
o Mannose-binding protein
o Contact-dependent metalloproteinase
and several
o Contact-independent serine
proteinases
Acanthamoeba spp. Virulence factor
mediates adhesion by recognizing and binding to mannose
residues on the surface of host cells, particularly on corneal epithelial cells
Mannose-binding protein
The likely method taken by Acanthamoeba spp. to enter the CNS
Hematogenous
Acanthamoeba spp. neural tissue postmortem reveals cerebral hemispheres that are
___________________, with areas of ____________________
edematous and soft
hemorrhage and focal abscesses
Acanthamoeba spp. most affected areas of the brain are the ___________________________________
posterior fossa structures,
thalamus, and the brainstem.
Acanthamoeba keratitis is diagnosed by
______________________________ for
recoverable ameba with characteristic staining
patterns on histologic analysis.
epithelial biopsy or corneal scrapings
Acanthamoeba Disease
destruction of brain tissue and the
associated meningeal irritation.
Granulomatous Amebic Encephalitis
Medical treatment of AK (acanthamoeba keratitis)
clotrimazole combined with pentamidine, isethionate, and neosporin
Clinically apparent neurologic disease in
GAE usually heralds a fatal outcome within
_____________________
3 to 40 days
if the acanthamoeba infection is confined to more superficial areas. _____________________is the procedure of
choice.
Deep lamellar keratectomy
In GAE, Parasite adhesion and damage to
endothelial cell is made possible by secreting
the _________________________
mannose-binding protein
