Genus Bacillus

Question 1

Give some examples of biological warfare agents.

Answer 1

Tularemia, plague, botulism, anthrax.

Question 2

Describe the outbreak in Sverdlovsk, Russia in 1979.

Answer 2

94 people sick and 64 dead. Soviets blamed contaminated meat and denied link to biological weapons. Caused by faulty exhaust filter.

Question 3

What happened in 1992 in response to the Sverdlovsk, Russia outbreak?

Answer 3

President Yeltsin admitted outbreak related to military facility. Western scientists find victim clusters downwind from the facility.

Question 4

What happened in South Africa from 1978-1980?

Answer 4

Anthrax used by Rhodesian and S. African apartheid forces. Thousands of cattle died and 182 human deaths. Only in Black Tribal lands.

Question 5

What happened in the U.S. in 2001?

Answer 5

Anthrax located at a postal facility near the White House in D.C.

Question 6

What is the classification of Bacillus based on oxygen requirement?

Answer 6

Aerobic or facultative anaerobic.

Question 7

What are the general characteristics of bacillus?

Answer 7

Spore forming, rod shaped, gram + or gram variable.

Question 8

Where are bacillus organisms found?

Answer 8

Ubiquitous in nature particularly soil, decaying organic matter, dust, water, and some part of normal flora.

Question 9

Describe the temperature requirements of bacillus organisms.

Answer 9

Grows well at 25-37C. Vegetative form killed at 55C in an hour of moist heat. Spores hours in boiling water.

Question 10

Describe the appearance of bacillus organisms on agar.

Answer 10

Rough and textured rather than smooth; most usually produce hemolysis except for bacillus anthracis.

Question 11

Describe the appearance of B. anthracis.

Answer 11

Large, gram + rods with square ends that are arranged in short chains or filaments.

Question 12

What is the oxygen requirement classification of B. anthracis?

Answer 12

Obligate aerobe.

Question 13

What organism of the bacillus genus is not hemolytic?

Answer 13

B. anthracis (gamma-hemolysis on blood agar).

Question 14

What kind of spore does B. anthracis produce and when are they produced?

Answer 14

Produces ovoid endospores that are centrally located in the vegetative cell; produced in vitro not in vivo.

Question 15

Do B. anthracis organisms have a capsule?

Answer 15

Yes.

Question 16

How does B. anthracis present in cattle and sheep?

Answer 16

Sepsis.

Question 17

How does B. anthracis present in horses?

Answer 17

Sepsis and colitis.

Question 18

How does B. anthracis present in humans?

Answer 18

Either cutaneous or systemic.

Question 19

How does B. cereus present in humans?

Answer 19

Gastroenteritis.

Question 20

How does B. licheniformis present in cattle and sheep?

Answer 20

Abortion and mastitis.

Question 21

How does B. subtilis present in cattle and sheep?

Answer 21

Abortion and mastitis.

Question 22

How does Paenibacillus larvae present in honeybees?

Answer 22

American foulbrood disease.

Question 23

Is B. anthracis motile?

Answer 23

No.

Question 24

Describe the distribution of B. anthracis.

Answer 24

Over 1,200 strains distributed worldwide.

Question 25

What are the sporulation requirements of B. anthracis?

Answer 25

Poor nutrient conditions, presence of oxygen.

Question 26

What are the characteristics of bacillus spores?

Answer 26

Very resistant, survive for decades, taken up by hosts and germinate.

Question 27

What is the lethal dose of bacillus spores?

Answer 27

2,500 to 55,000 spores.

Question 28

What are the 2 forms of B. anthracis?

Answer 28

Vegetative, spore.

Question 29

What are the virulence factors of B. anthracis?

Answer 29

Polypeptide capsule, exotoxin complex.

Question 30

What are the components of the exotoxin complex of B. anthracis?

Answer 30

Protective Ag: immunogenic and leads to produce PA63 fragment (binding factor). Edema factor (adenylate cyclase): binds to PA63 on host cell and converts ATP to cAMP. Lethal factor: binds to PA63 on host cell and is membranolytic.

Question 31

What are the methods of transmission of B. anthracis?

Answer 31

Ingestion, inhalation, skin abrasions, mechanical (insects).

Question 32

Describe the pathogenesis of B. anthracis.

Answer 32

Germination of endospores in the mucosa of the throat or in the intestines, persistent bacteremia, vascular permeability, thrombosis, hemorrhage, shock.

Question 33

What is the most common mechanism of transmission of B. anthracis?

Answer 33

Ingestion: herbivores via contaminated soil or heavy rainfall/drought, carnivores via contaminated meat.

Question 34

Describe animal transmission of B. anthracis.

Answer 34

Bacteria present in exudate from mouth, nose, and anus. Spores form and contaminate soil once they are exposed to oxygen. Spores are viable for decades.

Question 35

Sporulation _____________ occur in a closed carcass.

Answer 35

Does not.

Question 36

What species are most susceptible to B. anthracis?

Answer 36

Cattle, sheep, and goats.

Question 37

What species have intermediate susceptibility to B. anthracis?

Answer 37

Horses and humans.

Question 38

What species have the lowest susceptibility to B. anthracis?

Answer 38

Pigs, birds, and carnivores.

Question 39

What are the 3 forms of B. anthracis clinical signs and what species normally get each type?

Answer 39

Peracute: ruminants. Acute: ruminants and equine. Subacute/chronic: swine, dogs, cats.

Question 40

Who are at the greatest risk of developing clinical signs of B. anthracis?

Answer 40

Ruminants.

Question 41

What are the signs seen with peracute, acute, and chronic B. anthracis?

Answer 41

Peracute: sudden death. Acute: tremors, dyspnea, and bloody discharge from body orifices. Chronic (rare): pharyngeal/lingual edema and asphyxiation.

Question 42

How will a ruminant spleen appear in the case of B. anthracis?

Answer 42

Enlarged, dark, and soft-textured.

Question 43

What are the common differentials for B. anthracis in ruminants?

Answer 43

Blackleg, botulism, poisoning (plants, heavy metal, snake bite), lightning strike, babesiosis.

Question 44

What are the symptoms of acute anthrax in equine?

Answer 44

Fever, anorexia, colic, bloody stool, swelling of neck, dyspnea, and asphyxiation, death in 1-3 days.

Question 45

What are the symptoms of subacute to chronic anthrax in pigs?

Answer 45

Localized swelling of the throat, dyspnea, and asphyxiation, anorexia, vomiting/diarrhea.

Question 46

True or false: acute septicemia and sudden death are common results of anthrax in pigs.

Answer 46

False, it is uncommon to see this happen due to anthrax in pigs.

Question 47

Localized anthrax in pigs produces what signs?

Answer 47

Acute pharyngitis; swelling and hemorrhage of the throat/head, lymphadenitis.

Question 48

Carnivores are relatively _______ to anthrax.

Answer 48

Resistant.

Question 49

What are the symptoms of subacute to chronic anthrax in carnivores?

Answer 49

Fever, anorexia, weakness, necrosis and edema of upper GIT, lymphadenopathy/edema of head and neck, death due to asphyxiation, toxemia, or septicemia.

Question 50

Are there vx available for anthrax?

Answer 50

Yes for livestock in endemic areas, no vx for U.S. pets, but used in other countries, working dogs may be at risk.

Question 51

What type of vx is the anthrax vaccine?

Answer 51

Sterne strain which is live encapsulated spores.

Question 52

What are the different types of human anthrax?

Answer 52

Cutaneous (malignant pustule), pulmonary (woolsorters disease), intestinal.

Question 53

How do humans acquire each type of anthrax?

Answer 53

Cutaneous: wound contamination or biting flies. Pulmonary: inhalation of endospores from wool, hair, etc. Intestinal: ingestion of endospores via undercooked meat.

Question 54

Which types of people/occupations are most likely to contract anthrax?

Answer 54

Tanneries/textile mills, wool sorters/bone processors, slaughterhouses, laboratory workers.

Question 55

What are the virulence factors of B. cereus?

Answer 55

Exotoxins which are responsible for gastroenteritis.

Question 56

What is B. thuringiensis?

Answer 56

Insect pathogen of the bacillus genus.

Question 57

What are the virulence factors of B. thuringiensis?

Answer 57

Crystal toxins which disrupt gut when they are digested and liberate Cry toxin.

Question 58

Which bacillus species is used as a larvacide in mosquito control?

Answer 58

B. thuringiensis.

Question 59

Which bacillus species is largely non-pathogenic?

Answer 59

B. subtilis.

Question 60

What are the two forms of B. cereus?

Answer 60

Emetic form, diarrheal form.

Question 61

Describe the emetic form of B. cereus.

Answer 61

Incubation period less than 6 hours, severe vomiting, lasts 8-10 hours.

Question 62

Describe the diarrheal form of B. cereus.

Answer 62

Incubation period longer than 6 hours, diarrhea, lasts 20-36 hours.

Question 63

B. cereus causes what in cattle and sheep?

Answer 63

Abortion; gangrenous mastitis in cattle.