Lecture 31 - Hepatobiliary bacteria

Question 1

what bacteria are specific to the liver

Answer 1

1. fusobacterium necrophorum
2. clostridium spp.

Question 2

describe fusobacterium

Answer 2

gram - rod
anaerobe (tolerant)
grows at physiologic pH
ferments lactate

Question 3

habitat of fusobacterium

Answer 3

1. GI tract
2. oral cavity
3. genitourinary tract
4. soil contaminant

Question 4

what are fusobacterium virulence factors

Answer 4

1. hemolysin
2. hemagglutinin
3. adhesins
4. dermonecrotic toxin
5. platelet aggregation factor

Question 5

the endotoxin LPS does what

Answer 5

has necrotic effect on tissue to induce DIC and create an anaerobic environment

Question 6

how does leukotoxin work

Answer 6

protects the bacteria against phagocytosis from lymphoid cells

Question 7

describe how a liver abscess forms due to F. necrophorum

Answer 7

grain feeding and mucosal trauma allow for colonization nd spread via portal vein

Question 8

necrobacillosis

Answer 8

suppurative and necrotic with foul-smelling pus
high morbidity; low mortality

Question 9

fusobacterium in calves

Answer 9

calf diphtheria
damage to mucosa from feed, virus, or allergen and subsequent production of leukotoxin creates lesions in pharynx, larynx, oral cavity

Question 10

fusobacterium in cattle

Answer 10

hepatic necrobacillosis (liver abscess)
economically significant

Question 11

how is fusobacterium diagnosed

Answer 11

1. clinical signs
2. liver abscess at slaughter
3. anaerobic culture

Question 12

T/F: liver function tests are a good indicator of fusobacterium presence

Answer 12

FALSE

Question 13

in humans, fusobacterium is called

Answer 13

lemierre’s syndrome
pharynx and tonsils to jugular vein and abscesses

Question 14

how is fusobacterium treated and prevented

Answer 14

1. abx therapy
2. feedlot management

Question 15

describe clostridium spp.

Answer 15

gram + rods that form endospores and are motile anaerobes

Question 16

what is the habitat of clostridium species

Answer 16

1. GI tract
2. soil, freshwater, sediments

Question 17

what are endospores? what is their significance?

Answer 17

resistant, asexual spores that develop in a bacterial cell that survive conditions the cell would not normally

Question 18

what are the histotoxic clostridium

Answer 18

1. C. novyi
2. C. septicum

Question 19

T/F: histotoxic clostridium affect primarily grazing animals

Answer 19

TRUE

Question 20

infectious necrotic hepatitis

Answer 20

C. novyi type B
sheep
spores migrate to liver and are activated by liver damage (e.g. flukes)

acute death, no signs

Question 21

braxy

Answer 21

C. septicum
sheep
necrotizing abomastitis characterized by anorexia, depression, and fever

Question 22

how to diagnose histotoxic clostridium

Answer 22

1. cytology
2. anaerobic culture
3. fluorescent antibody staining
4. PCR (alpha-toxin)

Question 23

T/F: treatment for histotoxic clostridium is usually ineffective

Answer 23

TRUE

Question 24

while vaccination is available for histotoxic clostridium, what additional prevention measures should be taken for C. novyi

Answer 24

fluke control

Question 25

describe enteropathogenic/toxemic clostridium

Answer 25

species that replicate and produce elaborate toxins in the GI tract that are encapsulated to protect against phagocytosis

Question 26

what are the two important enteropathogenic/toxemic clostridium

Answer 26

1. C. perfringens 2. C. difficile

Question 27

Clostridium perfringens pathogenesis

Answer 27

requires the presence of intestinal clostridia AND altered enteric microenvironment

Question 28

hemorrhagic enteritis

Answer 28

C. perfringens in pigs type C = newborns, death type A = feeders/>2 weeks, chronic D+ and anorexia

Question 29

Lamb dysentery

Answer 29

C. perfringens type B first week of life abdominal distention, pain, and blood-stained feces

Question 30

Hemorrhagic enterocolitis

Answer 30

C. perfringens type C neonatal calves, foals, piglets, and lambs beta toxin susceptible to trypsin (low levels in newborns)

Question 31

C. perfringens diagnostics

Answer 31

1. sudden death in unvaxxed 2. post-mortem exam 3. samples 4. anaerobic culture 5. toxin detection

Question 32

why is it important to collect samples promptly

Answer 32

to avoid invasion of clostridium species from intestine to tissues

Question 33

treatment and control for C. perfringens

Answer 33

1. hyperimmune serum 2. vaccination 3. avoid sudden dietary changes

Question 34

what is a significant clostridial pathogen in human medicine

Answer 34

C. difficile

Question 35

what toxins are produced by C. difficile

Answer 35

A = enterotoxin B = cytoxin

Question 36

T/F: more hosts are colonized with C. dfficile than those that show clinical signs

Answer 36

TRUE

Question 37

T/F: C. difficile causes only hemorrhagic necrotizing enterocolitis

Answer 37

FALSE - range from enterocolitis to pseudomembranous

Question 38

what does C. difficile cause in dogs and horses

Answer 38

dog = chronic D+ foals = hemorrhagic enterocolitis

Question 39

what is an atypical clostridial organism

Answer 39

C. piliforme

Question 40

Tyzzer's Disease

Answer 40

C. piliforme foals 1-4 weeks old causes focal liver necrosis, acute fatal disease after brief illness

Question 41

match the scientific bacterial name to the common disease a. C. novyi b. C. piliforme c. C. septicum d. C. perfringens type B e. C. difficile 1. lamb dysentery 2. chronic D+ in dogs 3. infectious necrotic hepatitis 4. tyzzer's 5. braxy

Answer 41

a. 3 b. 4 c. 5 d. 1 e. 2