Clostridia

Question 0

C. perfringens toxins

Answer 0

produces 12 toxins
alpha-toxin (lecithinase): damages cell membranes and causes gas gangrene
phospholipase type C
hydrolyzes phosphatidylcholine and sphingomyelin that leads to cell death
muscle tissue is destroyed

Question 1

Describe C. perfringens

infection via, type of damage, toxin cause what

Answer 1

associated with wounds/damaged tissue
local damage and systemic effects
toxins cause cellulitis which can lead to gas gangrene

Question 2

C. perfringens infections can lead to what?

Answer 2

tissue damage

food poisoning

Question 3

C. perfringens tissue infections treatment and prevention

Answer 3

removal of infected muscle
antibiotics to control infection
prompt care is imperative- restore arterial blood supply
antitoxin from horses has relatively little effect
untreated 100% fatality rate- renal failure and shock usually result

Question 4

C. perfringens food poisoning

how common, toxin, symptoms, treatment

Answer 4

3rd most common type of food poisoning in US
produces enterotoxin in intestines after being consumed
diarrhea in 12-24 hrs
disappears in 1-3 days

Question 5

Describe C. botulinum

unique features, causative agent of disease

Answer 5

heat resistant spores may survive food processing
causative agent of botulism- preformed toxin, organisms don’t need to be present
bioweapon/bioterrorism threat

Question 6

C. botulinum toxins

how many, structure

Answer 6

8 neurotoxin (BoNT) serotypes A-G
very poisonous
900kDa protein complex
150kDa toxic componet
750kDa non-toxic binding component

Question 7

C. botulinum mechanism of action

type of paralysis, path of paralysis

Answer 7

prevents release of acetylcholine
flaccid paralysis in 12-36 hrs
cranial nerves affect first
paralysis desends

Question 8

Types of botulism

Answer 8

3 types
food borne
wound (rare)
infant (floppy baby, no honey, favorable outcome)

Question 9

C. botulinum treatment

mortality rate, antitoxin, antibiotics, damage

Answer 9

mortality rate 25%
administer antitoxin immediately
trivalent antitoxin from horses, administer ASAP
some muscle may be permanently damaged
no antibiotics

Question 10

Describe C. tetani

infection association, toxin, symptoms

Answer 10

infection associated with traumatic wounds (neonatal contamination of umbilical cord at delivery)
toxin: tetanospasmin
lockjaw is first symptom (80% of cases)
rigid/spastic paralysis
opisthotonos: characteristic arc

Question 11

C. tetani tetanospsmin mechanism of action

Answer 11

toxin invades neurons close to site of wound
toxins travel through neurons of periphery to cranial nerves
inhibits release of GABA (spastic paralysis)
paralysis descends down body

Question 12

C. tetani treatment and prevention and mortality

Answer 12

DPT vaccine
11% mortality
antitoxin along with penicillin G
cleaning of wound to prevent new bacteria growth
again antibiotics aren’t very affective and antitoxin must be administered before onset of symptoms

Question 13

Name the basic features of Clostridium

Answer 13

Gram positive rods
strictly anaerobic
produce endospores and toxins

Question 14

What are the common Clostriduim species we discussed?

Answer 14

4 of them
   C. difficile
   C. perfringens
   C. botulinum
   C.tetani

Question 15

Briefly describe the spore/vegetative cell cycle

Answer 15

vegetative cell is active
becomes spore in unfavorable conditions
spore part buds off then cell reuptakes it and peptidoglycan coat forms around spore
spore becomes active in favorable conditions

Question 16

Describe C. difficile

Answer 16

PMC
leading cause of nosocomial (antibiotic induced) diarrhea
spores are resistant to antibiotics
invasion of bowel wall doesn’t occur

Question 17

C. difficile: describe symptoms, toxin, toxin affects and toxin detection

Answer 17

diarrhea
2 toxins
toxin A: enterotoxin, prevents Na uptake= fluid loss
toxin B: cytotoxin, results in cell death
toxins act in cytoplasm and glycosylate GTP binding proteins-damages cell’s cytoskeleton
ELISA detection of toxin A