Bacillus

Question 1

What kind of Bacteria are Bacillus spp.?

Answer 1

Large Gram + rods, Endospore forming

Rapidly growing, aerobic or facultative anaerobes

Ubiquitous in nature

Most are soil saprophytes

Question 2

What kind of pathogen is Bacillus Anthracis?

Answer 2

An obligate mammalian pathogen

Question 3

What is the source of infection for herbivores in Bacillus anthracis infection?

Answer 3

Soil contaminated with spores

Question 4

What are the two main virulence factors of B. anthracis?

Answer 4

1. Capsule
2. Anthrax toxin

Both encoded by plasmids

Question 5

How is the B. anthracis capsule produced?

Answer 5

Only in vivo

Question 6

What are some characteristics of the B. anthracis capsule?

Answer 6

Polymers of D-glutamic acid

Encoded on plasmid

Anti-phagocytic

Stain pink

Question 7

What is a diagnostic feature of B. anthracis?

Answer 7

McFadyean reaction on staining with polychromatic methylene blue

Question 8

What are three factors of Anthrax toxin?

Answer 8

1. Edema factor
2. Lethal factor
3. Protective factor

Together these cause increased vascular permeability and cell necrosis

Question 9

What is the pathogenesis of B. antracis?

Answer 9

Spore Ingestion/exposure
Endospores germinate
Intracellular survival allow growth initiation
Capsule and edema factor inhibit phagocytosis
Vegetative cells grow rapidly
Complete anthrax toxin causes cell death and affects vascular permeability

Question 10

What are some predisposing factors that increase B. anthracis exposure?

Answer 10

History

Flooding

Soil conditions

Warm temperature

Drought conditions

Question 11

Who are the most susceptible to B. anthracis?

Least susceptible?

Answer 11

Cattle most susceptible

Pigs least susceptible

Question 12

How will most cattle with B. anthracis be found?

Answer 12

Found dead with unclothed blood and dark bloody fluid exuding form body cavities

Question 13

What is septicemia anthrax?

Answer 13

Death in 1-5 days, with massive spleen, extensive hemorrhages, bloody urine, blood from large bowel

Question 14

What is local anthrax?

Answer 14

Less susceptible species; severe edema at entry site, malignant carbuncle in skin (woolsorter’s disease of people)

Question 15

What can a biological warfare agent exposure lead to?

Answer 15

Multiple manifestations

Question 16

What are 6 common forms of anthrax?

Answer 16

1. Per acute septicemia=ruminants
2. Acute septicemia=horses
3. Pulmonary=man (wool sorters)
4. Pharyngeal=pigs, dogs
5. Intestinal=man, pigs, horse
6. Cutaneous=man (malignant carbuncle)

Question 17

What are some antemortem signs of per acute/acute septicemia of anthrax?

Answer 17

Rapidly fatal, high fever, bleeding from orifices, shock, respiratory distress

Question 18

What are some postmortem signs of per acute/acute septicemia of anthrax?

Answer 18

Dark, unclothed blood, incomplete rigor mortis, Splenomegaly

Question 19

Is Bacillus anthracis reportable? Why?

Answer 19

Yes, spores persist for decades in ground

Question 20

What should you do if you suspect anthrax as a differential DX:

Answer 20

DO NOT conduct field necropsy; call state/federal officials

Question 21

How would you DX anthrax?

Answer 21

McFadyean’s methylene blue; blue staining of organisms with a pink capsule

PCR

Aerobic culture of blood

Question 22

What BSL is anthrax?

Answer 22

BSL-3

Question 23

List the 3 ways anthrax is a zoonosis

Answer 23

1. Cutaneous=woolsorter’s disease (malignant carbuncle)
2. Aerogenous=pulmonary anthrax (bioterrorism)
3. Oral=intestinal and oropharyngeal anthrax

Question 24

Where should antimicrobial susceptibility testing for anthrax be done?

Answer 24

Approved referenced labs

Question 25

What drugs would be used to TX anthrax?

Answer 25

Penicillin, tetracycline, docycycline, ciprofloxacin

Question 26

How could anthrax be controlled?

Answer 26

Vaccinate healthy animals in endemic/high risk areas only