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RUSVM Bacteriology Exam 1 > Bacillus > Flashcards

Flashcards in Bacillus Deck (26)
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1
Q

What kind of Bacteria are Bacillus spp.?

A

Large Gram + rods, Endospore forming

Rapidly growing, aerobic or facultative anaerobes

Ubiquitous in nature

Most are soil saprophytes

2
Q

What kind of pathogen is Bacillus Anthracis?

A

An obligate mammalian pathogen

3
Q

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

A

Soil contaminated with spores

4
Q

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

A
  1. Capsule
  2. Anthrax toxin

Both encoded by plasmids

5
Q

How is the B. anthracis capsule produced?

A

Only in vivo

6
Q

What are some characteristics of the B. anthracis capsule?

A

Polymers of D-glutamic acid

Encoded on plasmid

Anti-phagocytic

Stain pink

7
Q

What is a diagnostic feature of B. anthracis?

A

McFadyean reaction on staining with polychromatic methylene blue

8
Q

What are three factors of Anthrax toxin?

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

Together these cause increased vascular permeability and cell necrosis

9
Q

What is the pathogenesis of B. antracis?

A

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

10
Q

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

A

History

Flooding

Soil conditions

Warm temperature

Drought conditions

11
Q

Who are the most susceptible to B. anthracis?

Least susceptible?

A

Cattle most susceptible

Pigs least susceptible

12
Q

How will most cattle with B. anthracis be found?

A

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

13
Q

What is septicemia anthrax?

A

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

14
Q

What is local anthrax?

A

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

15
Q

What can a biological warfare agent exposure lead to?

A

Multiple manifestations

16
Q

What are 6 common forms of anthrax?

A
  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)
17
Q

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

A

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

18
Q

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

A

Dark, unclothed blood, incomplete rigor mortis, Splenomegaly

19
Q

Is Bacillus anthracis reportable? Why?

A

Yes, spores persist for decades in ground

20
Q

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

A

DO NOT conduct field necropsy; call state/federal officials

21
Q

How would you DX anthrax?

A

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

PCR

Aerobic culture of blood

22
Q

What BSL is anthrax?

A

BSL-3

23
Q

List the 3 ways anthrax is a zoonosis

A
  1. Cutaneous=woolsorter’s disease (malignant carbuncle)
  2. Aerogenous=pulmonary anthrax (bioterrorism)
  3. Oral=intestinal and oropharyngeal anthrax
24
Q

Where should antimicrobial susceptibility testing for anthrax be done?

A

Approved referenced labs

25
Q

What drugs would be used to TX anthrax?

A

Penicillin, tetracycline, docycycline, ciprofloxacin

26
Q

How could anthrax be controlled?

A

Vaccinate healthy animals in endemic/high risk areas only