Clostridia

Question 1

What are the two pathogenic steps in establishing clostridia botulinum infections?

Answer 1

1) Toxins preformed in foods (botulin toxin)

2) Ingestion of microorganisms with adherence, colonization, and toxin formed in the gut (infant boluism)

Question 2

What is the metabolic status of clostridium?

Answer 2

Obligate anaerobe

Question 3

What is the morphology of clostridium?

Answer 3

gram positive rods with spores.

Question 4

How does clostridium test for oxidase and catalase?

Answer 4

Negative for both–because they are OBLIGATE ANAEROBES

Question 5

Which species of clostridium are noninvasive?

Answer 5

clostridium botulinum
clostridium tetani
clostridium difficile

Question 6

Which species of clostridium are invasive?

Answer 6

Clostridium perfringens
Clostridium septicum (in cancer)

Question 7

What are the effects of botulism toxin?

Answer 7

flaccid paralysis

Question 8

What are the effects of exotoxins A and B?

Answer 8

Diarrhea in pseudomembranous colitis from C. difficile

Question 9

What are the effects of alpha toxin?

Answer 9

lecithinase, which lyses host cell membranes and causes gas gangrene from clostridium perfringens

Question 10

Describe the morphology of Clostridium tetani

Answer 10

Gram + rod with a highly diagnostic “terminal spore”.

Question 11

How is clostridium tetani contracted?

Answer 11

through spores in the soil

Question 12

How many serological types of clostridium tetani are there?

Answer 12

One

Question 13

How many subunits does the tetanus toxin have? What does it do?

Answer 13

2 subunits. Binds to the neurotransmitter synapses, preventing neurotransmitter release of GABA and glycine

Question 14

What is the incubation period for tetanus?

Answer 14

4 days to weeks

Question 15

What are the symptoms of tetanus? (fevers, senses)

Answer 15

No fever, no sensory deficit, violent muscle spasms leading to respiratory failure and arched back

Question 16

How do you diagnose tetanus?

Answer 16

Mostly clinical symptoms and history because the organism is difficult to culture

Question 17

What are the treatment options for tetanus?

Answer 17

anti-toxin
penicillin
wound debridement
immunization
respiratory support if needed

Question 18

What is the dosage schedule of tetanus?

Answer 18

3 doses in the first six months
booster at 1 year
booster every 10 years

Question 19

How would you treat a dirty wound with uncertain immunization?

Answer 19

anti-tetanus toxin

Complete immunization

Question 20

What is the morphology of clostridium botulinum?

Answer 20

Gram + rod with subterminal oval spores

Question 21

How would you get rid of botulism toxin?

Answer 21

heat labile–cook to inactivate the toxin

Question 22

What are the three types of botulism?

Answer 22

Food botulism
Wound associated botulism- spore germination in wound
Infant botulism - Ingestion and colonization of GI tract

Question 23

What are the different serotypes of botulism toxin?

Answer 23

A, B, and E are the most common

A-G toxins

Question 24

What is the mechanism of action for botulism toxin?

Answer 24

absorption in intestine, carried to peripheral nerve synapses, and blockage of acetylcholine

Question 25

What are the symptoms of botulism?

Answer 25

``` flaccid paralysis (symmetrical), no fever, normal mental status dysphagia dry throat diluted pupils NO SENSORY defect ```

Question 26

What is the incubation period of botulism toxin?

Answer 26

18-36 hours

Question 27

How do you diagnose botulism?

Answer 27

Clinical diagnosis Detection of botulism toxin Electromyography

Question 28

Is a culture of clostridium botulinum from a patient sample sufficient for a diagnosis?

Answer 28

No. Need the presence of toxin.

Question 29

How do you treat Clostridium botulism?

Answer 29

Lavage--emptying of stomach Treatment with antitoxin, must be serotype specific Supportive care

Question 30

How can you prevent botulism?

Answer 30

Cooking food

Question 31

What is a common source of contamination with infant botulism?

Answer 31

honey

Question 32

What are the symptoms of infant botulism?

Answer 32

Constipation Flaccidity Cranial nerve deficit

Question 33

What is the morphology of Clostridium difficile?

Answer 33

Gram + rod

Question 34

What does exotoxin A bind to?

Answer 34

Enterotoxin that binds to the gut receptor

Question 35

What does exotoxin B bind to?

Answer 35

ADP-ribosylates Rho, damaging the colonic mucosa and formation of pseudomembrane

Question 36

What are the clinical symptoms of C difficile?

Answer 36

diarrhea with pseudomembrane visualized on colonoscopy | Diarrhea can be bloody sometimes

Question 37

How do you diagnose C difficile?

Answer 37

History of antibiotic use (ampicillin, cephalosporin, clindamycin) Eotoxin B detected in stool samples Sigmoidoscopy to visualize stool samples

Question 38

How can you treat C. difficile?

Answer 38

Stop the offending antibiotics | Treat with metronidazole, vancomycin, or fidaxomicin

Question 39

What are the causes of clostridium perfringens?

Answer 39

Surgical disease | Food poisoning-self limiting

Question 40

What are the symptoms of clostridium perfringens?

Answer 40

gas gangrene and tissue necrosis

Question 41

Where can clostridium perfringens be found?

Answer 41

soil, but also human GI tract+vagina

Question 42

What are the other species of clostridium that can also cause gas gangrene?

Answer 42

C septicum, C bifermentans and C ramosum, all anaerobes

Question 43

What is the morphology of clostridium perfringens?

Answer 43

A gram + rod

Question 44

What toxins does clostridium perfringens secrete?

Answer 44

lecithinase (alpha toxin) collagenase hyaluronidase (breaks down host matrix)

Question 45

What are the growth byproducts of C perfringens?

Answer 45

h2 and co2 gases

Question 46

What is unique about the growth of clostridium perfringens?

Answer 46

Rapid growth

Question 47

Are a lot of spores needed for clostridium perfringens food poisoning?

Answer 47

Yes, 10^8

Question 48

How does clostridium perfringens cause food poisoning?

Answer 48

After spores are ingested, the enterotoxin associated with the spore coat is released into the intestine

Question 49

What are the symptoms of clostridium perfringens gas gangrene?

Answer 49

Depends on where the bug is located. If gas gangerene is in skin=cellulitis. Necrotizing cellulitis, necrotizing fasciitis, myositis, myonecrosis

Question 50

What are the symptoms of clostridium perfringens food poisoning?

Answer 50

Abdominal cramps and watery diarrhea, usually resolved by 24 hours. It is the 2nd or 3rd most common cause of food poisoning

Question 51

How would you diagnose clostridium perfringens?

Answer 51

Crepitus, discoloration, and edema of the skin, which should be painful. Gram stain of fluid Culture of wound X-ray for gas in tissues If food poisoning, detect through ELISA enterotoxin in feces/food

Question 52

How would you treat gas gangerene by C. Perfringens?

Answer 52

Surgical-wound debridement Penicillin to kill remaining bacteria Hyperbaric oxygen if available. Fatal if untreated

Question 53

Why wouldn't you want to culture a clostridium tetanus wound?

Answer 53

Because the culture would only be positive 39% of the time.

Question 54

Which serotypes are most common in food botuulism?

Answer 54

A,B, and E. ABE likes to eat a lot which gives him food botulism. This is important because antitoxins are serotype specific

Question 55

Which serotypes are common in infant botulism?

Answer 55

F, A, B.

Question 56

Why wouldn't you want to culture a clostridium tetanus wound?

Answer 56

Because the culture would only be positive 39% of the time.

Question 57

Which serotypes are most common in food botuulism?

Answer 57

A,B, and E. ABE likes to eat a lot which gives him food botulism. This is important because antitoxins are serotype specific

Question 58

Which serotypes are common in infant botulism?

Answer 58

F, A, B.

Question 59

Which antibiotics are notorious for causing C. Diff infections?

Answer 59

Cephalosporins, fluoroquinolones, and Clindamycin

Question 60

Which species of clostridium are non-motile?

Answer 60

Clostridium perfringens