Anaerobes

Question 1

Characteristics of Anaerobic Bacteria

Answer 1

1. most infections are of endogenous origin
2. Require anaerobic environment/devitalized tissue
3. Obligate anaerobes do not tolerate oxygen

Question 2

Gram Positive Anaerobes

Answer 2

spore forming (ex Clostridium)

Question 3

Gram Negative Anaerobes

Answer 3

not spore forming (ex Fusobacterium necrophorum)

Question 4

Sign of Anaerobic Infection

Answer 4

infection not responding to treatment with aminoglycosides

Question 5

What is a predisposing factor to infection with Clostridium?

Answer 5

necrosis

Question 6

Major types of Disease caused by Clostridium

Answer 6

1. neurotoxic- toxic to nerves
2. Histotoxic- affect tissues
3. Enterotoxic- damage GI tract

Question 7

Neurotoxic Clostridium

Answer 7

C. botulinum, C. tetani, C. perfringens

Question 8

Histotoxic Clostridium

Answer 8

C. chauvoei, S. septicum, C. novyi,

Question 9

Enterotoxic Clostridium

Answer 9

C. perfringens, C. difficile

Question 10

Clostridium tetani

Answer 10

causes tetanus. Produces potent neurotoxin. More common in horses.

Question 11

Clostridium tetani pathogenesis

Answer 11

1. wound infection
2. toxin produced in wound
3. toxin enters motor nerves
4. retrograde transport
5. prevents release of neurotransmitters glycine and GABA
6. spastic paralysis

Question 12

What neurotoxin is produced by Clostridium tetani?

Answer 12

Tetanospasmin

Question 13

Ascending tetanus

Answer 13

occurs in less susceptible animals (dogs and cats)

Question 14

Descending Tetanus

Answer 14

occurs in more susceptible species (horses and humans)

Question 15

Clostridium tetani Diagnosis

Answer 15

clinical signs and history of recent wound. Culture often unrewarding and serology not useful

Question 16

Clostridium tetani Treatment

Answer 16

antitoxin, antimicrobial, supportive care

Question 17

Clostridium tetani Control

Answer 17

immunization, wound management, aseptic techniques

Question 18

Clostridium botulinum

Answer 18

causes botulism.

Question 19

Botulism

Answer 19

caused by food intoxication due to consumption of food contaminated with botulinum neurotoxin. Inhibits neurotransmitter release (acetylcholine) and causes flaccid paralysis

Question 20

Botulism clinical signs

Answer 20

symmetrical flaccid paralysis of muscles. Because of the lack of pathological changes and sometimes apparently vague symptomology such as downer cow, it can be missed as a diagnosis

Question 21

Botulism Diagnosis

Answer 21

not always practical.

Question 22

Botulism Treatment

Answer 22

antitoxin neutralizes unbound toxin only and is useful only if animal is still actively absorbing toxin, once toxin enters blood stream it is quickly bound to receptors

Question 23

Black Leg

Answer 23

caused by Clostridium chauvoei. Endospores are ingested and migrate through lymphatics or blood stream to muscle. Metabolic products of fermentation often have distinctive smells. Activation of endogenous spores in muscle

Question 24

Clostridium septicum

Answer 24

causes malignant edema (gas gangrene). Also causes Braxy in sheep and necrotic dermatitis in chicken

Question 25

Clostridium septicum Diagnosis

Answer 25

1. direct gram staining | 2. direct fluorescent antibody test

Question 26

Clostridium perfringens Type D

Answer 26

causes enterotoxin in sheep and goat (overeating disease). Focal symmetrical encephalomalacia. Rapid postmortem autolysis of the kidneys resulting in a pulpy kidney

Question 27

Clostridium difficile

Answer 27

Causes enterocolitis. Dysbiosis/dysbacteriosis

Question 28

Clostridium difficile Risk Factors

Answer 28

recent antibiotic use, old age, hospitalization

Question 29

Dysbiosis

Answer 29

general microbial imbalance of the body

Question 30

C. difficile Diarrhea Treatment

Answer 30

1. antimicrobials in severe cases 2. Probiotics- lactobacillus, Saccharomyces replaces flora 3. Avoid anti-diarrheals- result in accumulation of toxin 4. Fecal transplantation

Question 31

Clostridium spiroforme

Answer 31

causes explosive diarrhea in rabbits 4-8 weeks old. Antibiotics, lincomycin, clindamycin, and erythromycin are contraindicated in rabbits.

Question 32

Why are antibiotics contraindicated in rabbits?

Answer 32

they induce Clostridium-related enterotoxemia due to their selective effect on normal gram-positive bacteria

Question 33

Clostridium Piliforme

Answer 33

gram negative Clostridium that causes Tyzzers disease in lab animals. Cannot be cultured

Question 34

Tyzzers Disease

Answer 34

disease of lab animals caused by Clostridium piriforme. Associated with focal liver necrosis.

Question 35

Fusobacterium necrophorum

Answer 35

involved in liver abscess and foot rot in cattle and sheep

Question 36

General guidelines for treatment

Answer 36

aminoglycosides, sulfonamides are not effective. Antimicrobials. Depends on condition

Question 37

Anaerobic Bacteria Transmission

Answer 37

spread by direct extension from mucosal surfaces

Question 38

General Guidelines for Prevention

Answer 38

vaccination for foot rot. Hygiene and management of wounds

Question 39

Characteristics of necrosis

Answer 39

1. provides an initial opportunity for Clostridium to grow 2. the host response to many Clostridial infections 3. facilitates the rapid spread of infection through the body

Question 40

Anaerobic species

Answer 40

``` Clostridium tetani Clostridium botulinum Clostridium perfringes Clostridium difficile C. septicum C. chauveoi C. novyi ```

Question 41

What toxin is in all Clostridium perfringens?

Answer 41

Alpha Toxin

Question 42

Most lethal endotoxin produced by Clostridium perfringens

Answer 42

Epsilon toxin