Lecture 6- Clostridium Botulinum

Question 1

intoxication

Answer 1

ingestion or injection of the toxin

- intoxication of C. botulinum is fast but not as fast as s aureus

Question 2

infant botulism

Answer 2

ingestion and intestinal proliferation of the organism, internal production of the toxin

• common presentation is poor feeding and constipation
• symptoms include: poor feeding, loss of head control, visual problems, dry mouth, and generalized weakness. May lead to paralysis and respiratory failure
• spores are widespread and infants are thought to be repeatedly exposed
• honey imp. reservoir!

Question 3

wound botulism

Answer 3

deep wound results in anaerobic environment

Question 4

bioterrorism

Answer 4

deliberate delivery of toxin to large populations

Question 5

Pylogeny of C. botulinum

Answer 5

all c.botulinum strains are tocis

Question 6

Botulinium neurotoxin (boNT)

Answer 6

A-B toxin that consists of 2 subunits

- the toxin is inactive after production

Question 7

Nonproteolytic Cb

Answer 7

the hosts stomach acids cleave the toxin activating it

Question 8

Proteolytic Cb

Answer 8

the bacteria produce protease that activates the neurotoxin

Question 9

Where do the C. botulinum toxins go to after being ingested?

Answer 9

the toxin molecules are absorbed by the gut and are spread via the blood to peripheral nerves

Question 10

Describe the pathway of how Botulinum toxin gets inside the cell?

Answer 10

• following ingestion/production the toxin molecules are absorbed by the gut and are spread via the blood to peripheral nerves
• normally the axon terminal of the neuron connects with muscle tissues through SNARE PRO and release acetylcholine into the muscle cells which causes the contraction
• BoNT acts as a protease cleaving the SNARE PRO
• this deprives the muscle of acetylcholine signal and results in flaccid paralysis

Question 11

Name the 4 groups of the botulinum toxins

Answer 11

1. Group 1: C botulinum A and proteolytic strains of B and F (human)
   Group 2: C. botulinum E and glucidolytic strains of B and F (human)
   Group 3: C. botulinum C and D (animal)
   Group 4: C. botulinum G
   Type E toxin generally associated with fish
   Type A & B toxin are associated with fruits and vegetables

Question 12

What are the main properties of toxin Group 1?

Answer 12

• toxin type: A, proteolytic B and F
• proteolysis, lipase production is fast
• highly thermoresistant spores
• optimum growth temp: 37C
• minimum growth temp: 10-12C

Question 13

What are the main properties of toxin Group 2?

Answer 13

• toxin type: E, non-proteolytic B and F
• no proteolysis
• lipase production is fast
• moderately thermoresistant spores
• Optimum growth temp: 25C
• minimum growth temp: 2.5-3C

Question 14

How can BoNT toxin be carried?

Answer 14

carried either on the chromosome or on a plasmid

Question 15

C. botulinum

Answer 15

• survives by secreting numerous hydrolytic enzymes and then transporting the degredation products into the cell
• lacks several genes for aa synthesis
• strict anaerobe
• has fermentative metabolism
• many strains can use aa as their sole source of C and N
• adults must ingest BoNT to become sick, BoNT is produced in foods which become contaminated and have the right conditions for bacterial growth (anaerobic and high pH)

Question 16

Canning and C. botulinum

Answer 16

• spores are highly resistant to temp greater than 115C
• the toxin, however, is heat liable, so if canned goods are boiled for 10 min before consumption, this is not a porblem
• in natural environments, c. botulinum is outcompeted by other organisms and does not grow and produce toxin