6 - Clostridium Botulinum Flashcards by Anne-Sophie Hetu

The four faces of Clostridium botulinum:

1) Intoxication - ingestion (or injection) of the toxin
2) Infant Botulism - Ingestion and intestinal proliferation of the organism, internal production of the toxin (Infection)
3) Wound Botulism - Deep wound results in anaerobic environment
4) Bioterrorism - Deliberate delivery of toxin to large populations

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T OR F: By definition all C.botulinum strains are toxic

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Non-toxic variant strains, though genetically related, are assigned to different species such as: C.__________ and C.______________

sporogenes

subterminale

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Botulinum neurotoxin (BoNT) is an _____ toxin that consists of two subunits

A-B

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The toxin is __________ after production

inactive

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There are 2 types of Cb _____________ and ________________

proteolytic

nonproteolytic

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In nonproteolytic Cb the host’s ______________ cleave the toxin (activating it)

stomach acids

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In proteolytic Cb the bacteria produce a ___________ that activates the neurotoxin

protease

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Following ingestion the toxin molecules are _______________________________

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

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What happens when the Botulism toxin is ingested?

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 proteins and releases acetylcholine into the muscle cells which causes the muscle contraction
BoNT acts as a protease cleaving the SNARE proteins
This deprives the muscle of the acetylcholine signal and result sin flaccid paralysis
Major issues when it comes to lung or heart muscles

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There are several structurally similar, but immunologically distinct BoNTs distinguished using the letters _________

A to G

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Cb strains were grouped into ___ groups based on physiological differences, but these groupings don’t correlate to which groups produce which type of toxin

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Human illness is generally caused by Group _ and Group _ Cb

1 & 2

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Group 1: C. botulinum _ and proteolytic strains of _ and

_ (Human)

A
B
F

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Group 2: C. botulinum _ and non-proteolytic strains of _ and _ (Human)

E
B
F

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T OR F: Group 3: C. botulinum C and D (Animal)

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Group 4: C. botulinum _

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How do you test for Cb toxin?

1) Prepare food, feces, serum or gastric contents
2) Dispense filtrate into 3 tubes
3) no treatment tube, tube boiled for 10 min, trypsin asses to tube
4) Inject 2 mice with each tube
5) Treat No treatment tube with A toxin antiserum, B toxin Antiserum & F toxin Antiserum
6) Inject a mouse with each tube, the one that survives = you have to give that anti-toxin to the patient

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Main properties of Group 1 Cb:
toxin type:
proteolysis:
lipase production:
main physiological property:
optimum growth temp:
minimum growth temp:
causes botulism in:

A, proteolytic B,F
\+
\+
Highly thermoresistant spores
37C
10-12C
Humans

Main properties of Group 2 Cb:
toxin type:
proteolysis:
lipase production:
main physiological property:
optimum growth temp:
minimum growth temp:
causes botulism in:

E, non-proteolytic B,F
-
\+
Moderately thermoresistant spores
25C
2.5-3C
Humans

Cb genomes has a very low ______ content (27-28%)

G+C

Most strains also contain _______ that vary in size

plasmids

The BoNT toxin can be carried either on the ________ or on a _______

chromosome

plasmid

The similarity of the different BoNTs, the ability of different species to produce BoNT, and the fact that some strains contain combinations of bont genes suggests that all bont genes derive from a similar __________ – and move around

ancestor

Easy __________________ can be achieved by mobilization of the plasmids that carry BoNT toxins

horizontal transfer of genes

The possibility of C. ________ picking up a BoNT toxin is a serious concern

difficile

T or F: Cb is found almost ubiquitously in soils, you probably consume several spores daily

How does Cb survives?

By secreting numerous hydrolytic enzymes and then transporting the degradation products into the cell (such as AA, small peptides, carbohydrates)

Over ______ genes for transport systems have been identified

300

Cb lacks several genes for _____________

amino acid synthesis

Cb is a strict ___________

anaerobe (has a fermentative metabolism)

Cb is a ______________ microorganism that secretes various hydrolytic enzymes to uptake nutrients

saprophytic

Classic intoxication case:

harvesting a variety of low acids vegetables and doing home-canned soup, not checking the pH and not boiling for 10 mins before consumption

what is muktuk:

raw or fermented beluga whale blubber

Cb is sensitive to low pH and cannot germinate

4.6

Cb is sensitive to high salt and cannot germinate in more than ___% salt

5.5

In natural environments (or the human gut) Cb is ________________ by other organisms and does not grow and produce toxin

outcompeted

The toxin is heat ________, so if canned goods are boiled for 10 minutes before consumption, this is not a problem

liable

What are some foods associated with C.botulinum:

- fermented fish (E toxin) | - low acid fruits and vegetables (A & B toxin)

In adults how do we treat botulism?

with an antitoxin antibodies

In babies how do we treat botulism?

antibiotics + antitoxins antibodies

Does the baby infected with botulism has fever?

In wound botulism, the __________ makes the toxin

concentration

Clostridium botulinum spores are found to be _________ in the environment

widespread

They are routinely consumed by adults who are resistant to colonization due to _____________________

healthy gut microbiomes

T OR F: Adults must ingest BoNT to become sick, BoNT is produced in foods which become contaminated and have the right conditions for bacterial growth (anaerobic, pH above 4)

T OR F: Infants can become colonized with Clostridium botulinum, BoNT is produced in the child’s gut and child displays Infant Botulism (Infection)