ACANTHAMOEBA SPP.

Question 1

Common associated disease or condition names:

Answer 1

Granulomatous amebic encephalitis (GAE), Acanthamoeba keratitis

Question 2

Spinelike pseudopods, known as
_____________, project outward from the base of the organism.

Answer 2

acanthopodia

Question 3

________________ are the specimen of choice for recovery of Acanthamoeba infections of the eye.

Answer 3

Corneal scrapings

Question 4

Suspected corneal scrapings may be cultured on ___________________ plates seeded with gram-negative bacteria (specifically, a viable strain of E. coli).

Answer 4

non-nutrient agar

Question 5

Although primarily used to detect fungi in clinical specimens, ___________ may be used to stain Acanthamoeba cysts present in corneal scrapings.

Answer 5

calcofluor white

Question 6

________________________________ staining is the technique of choice for speciating Acanthamoeba.

Answer 6

Indirect immunofluorescent antibody

Question 7

Trophozoites and cysts enter via the
________________________________ in
the mucosa or skin.

Answer 7

lower respiratory tract or through ulcers

Question 8

Two groups of individuals are at risk for
direct eye invasion

Answer 8

contact lens wearers and those who have experienced trauma to the cornea

Question 9

Contact lens wearers who use homemade, nonsterile saline solutions that are contaminated with Acanthamoeba typically suffer a serious eye infection, known as

Answer 9

Acanthamoeba keratitis

Question 10

It is important to note that unlike N.
fowleri, which is associated with swimming or bathing in contaminated water, Acanthamoeba spp. infection is not associated with water but rather with __________________

Answer 10

contaminated saline

Question 10

Acanthamoeba infections of the cornea of the eye are known as ____________.

Answer 10

amebic keratitis

Question 11

Acanthamoeba shares many characteristics with the gram-negative bacteria ______________, which frequently occurs in standing water as an eye pathogen, but they are usually not recovered simultaneously from the same patient

Answer 11

Pseudomonas aeruginosa

Question 12

It is believed that _____________ inhibits the activity of Acanthamoeba spp.

Answer 12

P. aeruginosa

Question 13

Acanthamoeba is characterized by an active trophozoite stage with characteristic prominent ____________ appendages (acanthopodia);

Answer 13

“thorn-like”

Question 14

Motile trophozoites feed on gramnegative bacteria, blue-green algae, or yeasts and
reproduce by binary fission, but can also adapt to feed on corneal epithelial cells and neurologic tissue through ____________ and ______________________

Answer 14

phagocytosis , secretion of lytic enzymes

Question 15

Small, spiny filaments for locomotion
known as ___________ are evident on phase-contrast microscopy

Answer 15

acanthapodia

Question 16

Entry can occur through the
eye, the nasal passages to the lower respiratory tract, or ulcerated or broken skin

Answer 16

True

Question 17

Acanthamoeba spp. have been implicated as
possible reservoir hosts for medically important bacteria such as Legionella spp., mycobacteria, and gram-negative bacilli such as E. coli.

Answer 17

True

Question 18

Primary amebic infection or secondary bacterial infection may lead to __________________

Answer 18

hypopyon formation

Question 19

Progression of infection may cause ______ and _______, and may ultimately lead to vision loss.

Answer 19

scleritis, iritis

Question 20

The most affected areas of the brain are the posterior fossa structures, thalamus, and the brainstem.

Answer 20

True