Deck 15: Bacillus and Similar Organisms

Question 1

Which of the following types of anthrax occurs after ingesting the spores and affects the abdominal or oropharyngeal area? (Patients usually die from toxemia and overwhelming sepsis.)

A) Cutaneous
B) Pulmonary
C) Gastrointestinal
D) Bubonic

Answer 1

C
Gastrointestinal anthrax can be fatal as a result of toxemia and an overwhelming sepsis that cannot be controlled.

Question 2

Which of the following is described as a spore-forming, gram-positive Bacillus that is beta-hemolytic, motile, Voges-Proskauer (VP)-positive, and citrate-positive and causes two types of food poisoning as a result of toxin release?

A) Corynebacterium diphtheria
B) Bacillus anthracis
C) Bacillus cereus
D) Corynebacterium jeikeium

Answer 2

C
B.cereus is another important species to identify.It is resistant to penicillin, beta-hemolytic, and motile, and it produces a wide zone of lecithinase on egg yolk agar.

Question 3

Suspect spore-forming, gram-positive Bacillus species that is nonhemolytic, nonmotile, and penicillin-susceptible and that produces a wide zone of lecithinase on egg yolk agar can be identified as:

A) Corynebacterium diphtheria.
B) Bacillus anthracis.
C) Bacillus cereus.
D) Corynebacterium jeikeium.

Answer 3

B
B.anthracis should be suspected if typical nonhemolytic "Medusa head" colonies are observed on 5% sheep blood agar and if the organism is subsequently found to be nonmotile and lecithinase-positive.

Question 4

A patient diagnosed with Bacillus anthracis is allergic to penicillin.Which antibiotic can be given that will be therapeutically effective?

A) Ampicillin
B) Ciprofloxacin
C) Imipenem
D) Vancomycin

Question 5

Enzyme-linked immunosorbent assays (ELISAs)are available that can serologically identify which Bacillus species?

A) B. cereus
B) B. subtilis
C) B. thuringiensis
D) B. anthracis

Question 6

A U.S.Food and Drug Administration (FDA)-cleared immunochromatographic test produces a red line on the cassette and can presumptively identify which gram-positive Bacillus that is nonhemolytic and morphologically has a "Medusa head" appearance when grown on 5% sheep blood agar?

A) Bacillus subtilis
B) B. cereus
C) B. mycoides
D) B. anthracis

Question 7

Induction of sporulation by Bacillus species can be accomplished with _____ agar.

A) 5% sheep blood
B) PLET acetate
C) bicarbonate
D) urea

Question 8

Induction of capsule formation by B.anthracis can be accomplished with _____ agar.

A) 5% sheep blood
B) PLET acetate
C) bicarbonate
D) urea

Question 9

Media that can be used for isolating Bacillus anthracis include:

A) Thayer-Martin agar.
B) 5% sheep blood agar.
C) MacConkey agar.
D) Columbia blood agar with colistin-nalidixic acid (CNA).

Question 10

A gram-positive Bacillus, which is beta-hemolytic on 5% sheep blood agar, produces a wide zone of lecithinase on egg yolk agar, is nonmotile, and was isolated from the stool of a patient with abdominal pain and watery diarrhea.Because of the patient's existing immunocompromised state, the physician administered penicillin as the antibiotic therapy.The patient's condition did not improve after 7 days of treatment.Which one of the following statements explains the reason for the antibiotic failure?

A) The course was too abbreviated and should be given for 14 days.
B) The patient may be allergic to penicillin and its therapeutic effects.
C) Penicillin is ineffective against gram-positive organisms.
D) The organism produces beta-lactamase, which renders the drug inactive.