Deck 36: Francisella

Question 1

To cultivate Francisella in the laboratory,a medium supplemented with which of the following ingredient(s)is necessary?

A)Cysteine and cystine
B)Blood and cysteine
C)Dopa-cysteine
D)Nicotinic adenine

Answer 1

A
Blood,chocolate,and MacConkey agars cannot be used for the primary isolation of organisms belonging to the genus Francisella.Francisella is a facultative,intracellular pathogen that requires cysteine and a source of iron for growth.

Question 2

The specimen of choice to collect in suspected cases of Francisella tularensis is:

A)blood.
B)cerebrospinal fluid (CSF).
C)lymph nodes.
D)urine.

Answer 2

C
The most common specimens submitted to the laboratory are scrapings from infected ulcers,lymph node biopsies,and sputum.

Question 3

Tularemia,characterized by glandular,ulceroglandular,oculoglandular,oropharyngeal,systemic,and pneumonic presentations,is caused by which of the following species?

A)Brucella
B)Bordetella
C)Pasteurella
D)Francisella

Answer 3

D
F.tularensis is the agent of human and animal tularemia.Worldwide in distribution,F.tularensis is carried by many species of wild rodents,rabbits,beavers,and muskrats in North America.Humans become infected by handling the carcasses or skin of infected animals,through insect vectors (i.e. ,primarily deerflies and ticks in the United States),by being bitten by carnivores that have themselves eaten infected animals,or by inhalation.

Question 4

Which assay is available to identify F.tularensis serologically?

A)Complement fixation
B)Direct fluorescent antibody test
C)Immunodiffusion assays
D)Enzyme-linked immunosorbent assays (ELISAs)

Question 5

Francisella philomiragia differs from F.tularensis in that it:

A)is oxidase-negative.
B)is hydrogen sulfide-positive.
C)does not hydrolyze gelatin.
D)does not grow in 6% sodium chloride.