Deck 48: Protozoa From Other Body Sites

Question 1

The Acanthamoeba organism is motile and has spinelike pseudopods,a single round nucleus in the cyst form,and a large karyosome in the nucleus of the troph.An estimated 70% of clinical cases of Acanthamoeba keratitis are misdiagnosed as __________ keratitis.

A)bacterial
B)fungal
C)prion
D)viral

Answer 1

D
An estimated 70% of patients with clinical Acanthamoeba keratitis are misdiagnosed as having viral keratitis.In addition,the average time to diagnosis keratitis as a result of an Acanthamoeba infection can average 2.5 weeks longer for noncontact lens wearers than for contact lens wearers.

Question 2

The CSF would reveal which of the following results in infections caused by N.fowleri?

A)Increased glucose,increased protein,and positive Gram stain
B)Decreased glucose,decreased protein,and negative Gram stain
C)Decreased glucose,increased protein,and negative Gram stain
D)Increased glucose,decreased protein,and positive Gram stain

Answer 2

C
An analysis of the CSF of N.fowleri infections will show decreased glucose and increased protein concentrations.The leukocyte count will range from several hundred to greater than 20,000 cells per mm³.Although Gram stains and bacterial cultures of CSF will be negative,serious patient complications can occur as the result of incorrect therapy if false-positive Gram stains are reported.

Question 3

MATCHING
Match the infectious stage of T.gondii with the appropriate description.
a.Crescent-shaped
b.Oocysts from cat feces
c.Tissue cysts
Tachyzoites

Answer 3

A

Question 4

A 15-year-old male was diving in a lake when he inhaled some of the stagnate water.Five days later he was admitted to the hospital,comatose,and in critical condition.A cerebrospinal fluid (CSF)specimen was taken,and several motile amoebae were observed.The patient would most likely be diagnosed with which of the following conditions?

A)Granulomatous amebic encephalitis
B)Primary amebic meningoencephalitis
C)Secondary amebic encephalitis
D)Chronic granulomatous meningitis

Question 5

Trichomoniasis is the primary nonviral sexually transmitted disease worldwide.One complication of this infection is:

A)keratitis.
B)endometritis.
C)meningitis.
D)appendicitis.

Question 6

The troph of the motile T.vaginalis organism measures 7 to 23 mm long and 5 to 15 mm wide.The recommended treatment of choice for this urogenital infection is:

A)tetracycline.
B)metronidazole.
C)penicillin.
D)ketoconazole.

Question 7

Tissues suspected of containing Acanthamoeba cysts can be observed using various stains.A cyst that stains black has most likely been stained with the __________ stain.

A)methenamine silver
B)periodic acid-Schiff (PAS)
C)Giemsa
D)Wright's

Question 8

A 26-year-old woman has an odorous vaginal discharge,lower abdominal pain,and difficulty urinating.Vaginal secretions are collected and sent to the laboratory for examination 3 hours after collection.No motile organisms are observed on the wet preparation;however,T.vaginalis is suspected.Which one of the following statements explains this discrepancy?

A)The infection is most likely bacterial;therefore a Gram stain should have been performed.
B)The specimen should have been refrigerated before examination;consequently,the organism was compromised.
C)The time between collection and the microscopic examination was prolonged,resulting in loss of motility.
D)No discrepancy is present;this organism in nonmotile.

Question 9

MATCHING
Match the infectious stage of T.gondii with the appropriate description.
a.Crescent-shaped
b.Oocysts from cat feces
c.Tissue cysts
Sporozoites

Question 10

Primates,as well as dogs,sheep,and horses,have died of central nervous system (CNS)infections with which organism?

A)N.fowleri
B)Acanthamoeba spp.
C)Toxoplasma gondii
D)Balamuthia mandrillaris

Question 11

MATCHING
Match the infectious stage of T.gondii with the appropriate description.
a.Crescent-shaped
b.Oocysts from cat feces
c.Tissue cysts
Bradyzoites

Question 12

Laboratory diagnosis of T.gondii is confirmed by:

A)Giemsa stain.
B)tissue culture.
C)serologic testing.
D)Western blot.