Clostridium

Question 1

Clostridium oxygen requirements

Answer 1

Most strains are strict anaerobes

Question 2

Clostridium found…

Answer 2

In soil and water, some are normal intestinal flora (difficile)

Question 3

Clostridium culture/morphology

Answer 3

Endospore forming

Question 4

Clostridium virulence factors

Answer 4

Many strains produce powerful toxins and exoenzymes (botulinum and tetanus)

Question 5

4 different Clostridium strains

Answer 5

1. Clostridium botulinum
2. Clostridium Tetani
3. Clostridium Perfinges
4. Clostridium difficile

Question 6

Clostridium botulinum mechanism of action

Answer 6

Incredibly powerful exotoxins-works at neuromuscular junction and in the autonomic nervous system to prevent the release of acetylcholine (flaccid paralysis)
AB toxin that has one part for binding, one part for activity

Question 7

Clostridium botulinum diseases

Answer 7

Causes botulism- in US usually following ingestion of inadequately processed home-canned food. Incubation of ingested toxin to produce disease 8hrs-8days.
—Symptoms: nausea, vomiting, and diarrhea followed by symmetric, descending paralysis (eyes, throat, neck, trunk, then limbs. Death caused by paralysis of respiratory muscles

Question 8

Clostridium tetani exotoxins/ virulence factors

Answer 8

A-hemolysin

Tetanospasmin

Question 9

Clostridium tetani tetanospasmin

Answer 9

Binds to sailings acid gangliosides in CNS to prevent the release of inhibitory neurotransmitter GABA and glycine from synapses in spinal chord. Leads both sets of muscles (agonist and antagonis) contracting at the same time and spastic paralysis. Contractions can be so strong to break bones/ joints, such as the spine.

Question 10

Clostridium tetani pathogenesis

Answer 10

Spores enter body through wounds- incubation average 5-15 days (LONGER incubation shows better prognosis) symptoms start with cramps and twitching muscles around wound, headache and sore neck. Death (if occurs) happens within 4 days due to respiratory failure.

Question 11

Clostridium perfingens toxins

Answer 11

All types produces alpha toxin: lethal, necrotizing lecithinase (outer zone of hemolysis)
Enzymes that destroy cell structure: gelatinase, collagenase, protease, DNAase, neuraminidases
A few types produce enterotoxin responsible for causing intoxication-type food poisoning in meats, poultry and gravy (cholera-similar action)

Question 12

Clostridium perfingens gas gangrene

Answer 12

Anaerobic cellulitis: gas accumulation, discoloration, malodorous brown, purulent discharge— invasion of healthy muscle tissue surrounding the wound site (myonecrotic)

Question 13

Clostridium difficile pathogenesis

Answer 13

GI infection can be caused by antibiotic use killing off normal microflora- allowing Clostridium difficile to reign supreme. Can result in distress, up to pseudomembranous colitis (colonic plaques)

Question 14

Clostridium difficile toxins

Answer 14

Two exotoxins, both of which inactivate Rho proteins by adding glucose, as well as enterotoxin A that stimulates fluid and electrolyte losses from the intestinal tract.

Question 15

Clostridium tetani treatment

Answer 15

Administer antitoxin (toxin that’s already in the CNS can’t be neutralized) maintain open airway, remove infected tissue, VACCINATION (though need booster every 10 years)

Question 16

Clostridium botulinum treatment

Answer 16

Administer antitoxin before moves into tissues- requires aggressive respiratory support, otherwise complete respiratory failure. Wound treatment: debridement and antibiotics: hyperbaric chamber (anaerobe)

Question 17

Clostridium difficile treatment

Answer 17

Metronidazole and vancomycin: fluid and electrolyte replacement