Lecture 10 9/27/23

Question 1

What are the general characteristics of anaerobic bacteria?

Answer 1

-need anaerobic environment
-do not tolerate oxygen
-must transport anaerobically
-can be gram pos. or gram neg.
-polymicrobial infections are common

Question 2

What signs are consistent with anaerobic infection?

Answer 2

-foul smelling
-gas buildup
-necrotic tissue
-abscesses
-pyogranulomatous lesions w/ sulfur granules
-infections near mucous membranes
-not responsive to aminoglycosides
-disease despite negative aerobic culture

Question 3

What are the characteristics of Clostridium sp.?

Answer 3

-gram pos
-spore forming
-rods
-produce exotoxins

Question 4

What are the three major types of disease caused by Clostridium sp.?

Answer 4

-neurotoxic
-histotoxic
-enterotoxic

Question 5

Which Clostridium sp. causes all three types of disease?

Answer 5

C. perfringens

Question 6

What are the characteristics of C. tetani?

Answer 6

-causes tetanus
-grows in contaminated wounds
-produces potent neurotoxin
-can affect all species

Question 7

How does the C. tetani neurotoxin act on the body?

Answer 7

prevents release of glycine and GABA neurotransmitters, leading to spastic paralysis

Question 8

What is ascending tetanus?

Answer 8

toxin begins in limb and spreads to other parts of body; limbs affected first

Question 9

What is descending tetanus?

Answer 9

toxin in blood stream affects head and neck first; spread to limbs secondary

Question 10

How is C. tetani diagnosed?

Answer 10

clinical signs and wound history

Question 11

How can tetanus be treated?

Answer 11

-antitoxin
-anti-tetanus serum
-antimicrobials
-surgical debridement
-supportive care

Question 12

How can C. tetani be controlled?

Answer 12

-toxoid immunization
-post exposure prophylaxis
-proper wound management and aseptic techniques

Question 13

What are the characteristics of C. botulinum?

Answer 13

-causes botulism via botulinum neurotoxin
-disease caused by food intoxication
-most powerful exotoxin
-inhibits neurotransmitter release
-flaccid paralysis
-select agent

Question 14

How is C. botulinum diagnosed?

Answer 14

-demonstration of toxin in serum
-bioassay/neutralization tests
-ELISA

Question 15

How is C. botulinum treated?

Answer 15

-antitoxin
-therapeutic drugs
-supportive care

Question 15

How is C. botulinum controlled?

Answer 15

-toxoid vx. for high risk animals, but no routine vx.
-avoid feeding soiled food

Question 16

Which histotoxic Clostridia are of importance?

Answer 16

-C. chauvoei
-C. septicum
-C. novyi
-C. perfringens

Question 17

What disease is caused by C. chauvoei?

Answer 17

black leg

Question 18

What are the characteristics of black leg?

Answer 18

-ingested endospores lead to trauma and tissue necrosis
-distinctive smells of fermentation end products
-characteristic edematous and emphysematous swellings

Question 19

What diseases are caused by C. septicum?

Answer 19

-malignant edema
-braxy
-necrotic dermatitis

Question 20

What are the two types of malignant edema infections?

Answer 20

-exogenous through wounds
-endogenous through dormant spores in meat/tissue

Question 21

What infections are caused by C. novae?

Answer 21

-exogenous gas gangrene
-endogenous black disease
-endogenous liver damage and bacillary hemoglobinuria

Question 22

How can the histotoxic Clostridium sp. be diagnosed?

Answer 22

-gram stain
-fluorescent antibody staining test

Question 23

What antibiotic is used against histotoxic Clostridium sp.?

Answer 23

penicillin

Question 24

How can histotoxic Clostridium sp. be controlled?

Answer 24

routine vx

Question 25

What are the characteristics of C. perfringens?

Answer 25

-classified based on combinations of four toxins (alpha, beta, iota, epsilon) -all species have alpha toxin -cause enteric disease

Question 26

Which C. perfringens type is most important?

Answer 26

Type D

Question 27

What are the characteristics of C. perfringens type D?

Answer 27

-causes enterotoxemia -fluid-distended intestine with petechial hemorrhage -focal symmetrical encephalomalacia -pulpy kidney

Question 28

How is C. perfringens diagnosed?

Answer 28

-gram stain -anaerobic culture -toxin detection

Question 29

How is C. perfringens treated?

Answer 29

hyperimmune serum

Question 30

How is C. perfringens controlled?

Answer 30

-immunization -avoiding sudden changes in diet and stress

Question 31

What are the characteristics of C. difficile?

Answer 31

-causes enterocolitis -proliferate rapidly once antimicrobial treatment kills flora and is removed -risk factors include recent antibiotic use, old age, and hospitalization

Question 32

How is C. difficile diagnosed?

Answer 32

-culture -toxin antigen detection

Question 33

How is C. difficile treated?

Answer 33

-supportive care -stopping antimicrobials in most cases -using antimicrobials in severe cases -probiotics -fecal transplantation

Question 34

What are the characteristics of C. spiroforme?

Answer 34

-commensal that produces Iota toxin -causes enterotoxemia and explosive diarrheal disease in rabbits -some antibiotics are contraindicated and will instead induce disease

Question 35

What are the characteristics of C. piliforme?

Answer 35

-gram-neg. -causes Tyzzer's disease in lab animals -acute, fatal diarrhea and focal liver necrosis -cannot be cultured

Question 36

Which gram-negative non-spore forming anaerobe is of importance?

Answer 36

Fusobacterium necrophorum

Question 37

What are the characteristics of Fusobacterium necrophorum?

Answer 37

mucosal membrane and skin commensal -involved in liver abscess and foot rot

Question 38

How is Fusobacterium necrophorum diagnosed?

Answer 38

-anaerobic culture -PCR

Question 39

How is Fusobacterium necrophorum treated?

Answer 39

antimicrobials

Question 40

How is Fusobacterium necrophorum controlled?

Answer 40

-hygiene and management -vx to prevent foot rot