Clostridia

Question 1

2 Types of Anaerobes

Answer 1

1. Aerotolerant
2. Obligate/Strict

Question 2

Why do obligate anaerobes not tolerate any amount of oxygen?

Answer 2

they lack the enzymes to detoxify reactive oxygen species (superoxide dismutase, catalase, peroxidases)

Question 3

How are you able to culture strict anaerobes?

Answer 3

use a reducing agent in the medium

packets in the lab, something to absorb oxygen, reduce hydrogen peroxide, thioglycolate or metallic iron

Question 4

Anaerobiosis

Answer 4

Eh (standard reduction potential) falls below 150mV, anaerobes are able to grow

Question 5

Examples of Conditions which lower Eh values

Answer 5

Loss of vascular supply to tissue
Trauma, foreign bodies
Acid production
Tissue necrosis

Question 6

Are aerotolerant anaerobes gram positive or negative?

Answer 6

gram positive

Question 7

Are obligate anaerobes gram positive or negative?

Answer 7

gram negative

Question 8

Are anaerobe present in normal flora?

Answer 8

yes, they actually make up the majority

Question 9

Are anaerobes opportunistic?

Answer 9

yes! think that they’re normally present (endogenous) and then shit happens

Question 10

Do anaerobes cause infection on their own?

Answer 10

sometimes, but most are mixed infections

Question 11

Clostridia

Answer 11

large gram positive rods, most are motile, non-encapsulated, spore forming

Question 12

Which Clostridia species is NOT motile?

Answer 12

C. perfringens

Question 13

Blackleg disease organism

Answer 13

Clostridium chauvoei
(also C. novyi, septicum, or sordelli)

Question 14

Blackleg Disease Pathogenesis

Answer 14

C. chauvoei produces Phospholipase C (alpha toxin) which degrades phosphatidylcholine, which is the most abundant phospholipid on cell membranes

Question 15

Signs of Blackleg

Answer 15

gas gangrene in muscle tissue, myositis, gram positive bacteria in exudate

Question 16

Malignant edema organism (clostridial myositis)

Answer 16

Clostridium septicum

Question 17

Clostridium septicum pathogenesis

Answer 17

wounds, fractures, etc, but also due to IRRITATED STOMACH LINING by eating dry or icy feed; alpha toxin breaking down cell membranes

Question 18

Braxy

Answer 18

name of C. septicum infection in sheep

Question 19

Which Clostridium species causes red water disease (hemoglobinuria)?

Answer 19

Clostridium hemolyticum

Question 20

Clostridium hemolyticum pathogenesis

Answer 20

liver flukes cause liver infarcts (tracts/necrosis in the liver), bacteria grows and produces alpha toxin which then spreads systemically

Question 21

2 Groups of Disease-Causing Clostridia

Answer 21

1. Invasive group
2. Non-invasive group

Question 22

Which two Clostridia species are non-invasive?

Answer 22

C. tetani and C. botulinum

Question 23

Tyzzer’s Disease is caused by what organism?

Answer 23

Clostridium piliforme

Question 24

Toxin which mediates Tyzzer’s disease?

Answer 24

Iota toxin

Question 25

Appearance of C. piliforme on TEM

Answer 25

slender, thin, and long with peritrichous flagella

Question 26

2 Types of Disease Caused by C. piliforme

Answer 26

1. Necrotizing hepatitis 2. Hemorrhagic enteritis

Question 27

hemorrhagic enteritis

Answer 27

results in melena, diarrhea, and black color caused by the oxidation of iron

Question 28

Diagnosis of Tyzzer's (necrotizing hepatitis) on histopathology

Answer 28

long slender cells with a fuzzy appearance, lots of filaments in weird arrangements in hepatocytes on Giemsa staining

Question 29

Tyzzer's on Necropsy

Answer 29

disseminated small gray-white necrotic lesions with suppurative inflammation

Question 30

Clostridium perfringens

Answer 30

non-motile Clostridia species which causes enterotoxaemia (usually due to overeating)

Question 31

enterotoxaemia

Answer 31

toxin in blood from the gut

Question 32

Most common toxinotype of C. perfringens?

Answer 32

Type A

Question 33

C. perfringens in horses

Answer 33

causes necrotizing myositis, often associated with IM Banamine injection; causes gas; make incisions to expose bacteria to air

Question 34

Pulpy Kidney (Overeating) Disease

Answer 34

occurs in sheep due to Type D C. perfringens which produces lethal epsilon toxin

Question 35

Is C. perfringens a strict or aerotolerant anaerobe?

Answer 35

STRICT anaerobe

Question 36

Why is Type D C. perfringens linked to overeating?

Answer 36

the organism thrives on sugars and starches in the upper portion of the GI tract

Question 37

C. perfringens (Type D) Clinical Signs

Answer 37

colic, muscle tremors, convulsions, frothing, nystagmus, teeth grinding

Question 38

3 Toxins Produced by C. tetani

Answer 38

1. Tetanolysin 2. Tetanospasmin 3. Non-spasminogenic Toxin

Question 39

Tetanospasmin

Answer 39

potent A-B neurotoxin that blocks the release of inhibitory neurotransmitters (GABA and glycine)

Question 40

GABA

Answer 40

chief inhibitory neurotransmitter in the CNS, ensuring muscle relaxation by inhibiting motor neurons

Question 41

tetanic spasm

Answer 41

spastic paralysis, muscles are unable to relax due to the inhibition of GABA

Question 42

2 Forms of Botulism

Answer 42

1. Food-borne 2. Infant

Question 43

Food-borne botulism

Answer 43

intoxication (NOT infection) of preformed botulinum toxin

Question 44

Infant botulism

Answer 44

non-invasive infection of C. botulinum in young infants who have consumed solid foods containing botulinum spores

Question 45

C. botulinum pathogenesis

Answer 45

inhibits excitatory NT Ach in the PNS leading to flaccid paralysis, leading to respiratory arrest

Question 46

Target of Botulinum vs. Tetani

Answer 46

Botulinum = PNS Tetani = CNS

Question 47

DO botulinum and tetani have the same MOA?

Answer 47

yes - essentially the toxin degrade the SNARE proteins which are necessary for the fusion of the vesicle at the synapse for NT release

Question 48

4 Gram-Negative Anaerobic Rods

Answer 48

1. Fusobacterium necrophorum 2. Dichelobacter nodosus 3. Prevotella melaninogenicus 4. Bacteroides fragilis

Question 49

Can gram-negative anaerobic bacteria sporulate?

Answer 49

no!

Question 50

Only gram-negative anaerobic bacteria which can cause disease?

Answer 50

Fusobacterium necrophorum (this is the primary invader which must come first)

Question 51

Bacteriodes fragilis affects what species?

Answer 51

humans (can be domestic animals but not the point)

Question 52

Main disease caused by the gram-negative anaerobic bacteria discussed in class?

Answer 52

FOOT ROT!