Clostridium

Question 1

What is botulism?

Answer 1

A rare and potentially fatal paralytic illness

Caused by the botulinum toxin produced by the bacteria Clostridium botulinum

Question 2

What bacteria causes botulism?

Answer 2

Clostridium botulinum

Produces botulinum toxin

Question 3

What are the types of botulism?

Answer 3

Foodborne botulism - ingestion of food containing botulinum toxin
Wound botulism - spores enter body via wound
Infant botulism - bacteria develop in infant intestine and releases toxin into intestine

Question 4

What group of people are most commonly affected by wound botulism?

Answer 4

People who inject street drugs

Question 5

How long does it take for symptoms of botulism to appear after ingestion of toxin?

Answer 5

Symptoms usually appear between 18-36 hours after ingestion of toxin

However this can range from a few hours to several days, depending on the amount of toxin consumed

Question 6

What is the ultimate effect of botulinum toxin?

Answer 6

Prevent release of acetylcholine at the neuromuscular junction, resulting in flaccid paralysis

Question 7

What is infant botulism, what age does it affect and why?

Answer 7

Infant botulism - spores develop in the infant intestine and release botulinum toxin

Affects children under 6 months of age. After this age protective immune system mechanisms have developed which prevent damage

Question 8

What is the mortality rate for botulism?

Answer 8

5-10%

Question 9

What is the usual first symptom of infant botulism?

Answer 9

Constipation

Question 10

How can Clostridium botulinum be classified?

Answer 10

C. botulinum can be divided into four phenotypically distinct groups, denoted I-IV

Can also be classified into 7 serotypes, denoted A-G, based on the toxin it produces. There are 7 different antigenically and serologically different botulinum toxins

Question 11

How many botulinum toxins are there?

Answer 11

There are 7 serologically and antigenically different botulinum toxins, denoted A-G

In 2013 it was revealed an 8th toxin, H, had been discovered. Little information has been released since this announcement

Question 12

What is the eighth botulinum toxin and why is little known about it?

Answer 12

In October 2013, it was revealed an 8th botulinum toxin had been discovered. This was the first new botulinum toxin to be discovered in 40 years

Further information has not been released due to fears the toxin could be abused as a bioweapon and due to lack of a known antitoxin

Question 13

What are the proteolytic and non-proteolytic botulinum toxins?

Answer 13

Types A, and some of B & F are proteolytic

Types E, and some of B, C, D & F are non-proteolytic

Question 14

Why do non-proteolytic botulinum toxins often go undiscovered?

Answer 14

Proteolytic botulinum toxins (A and some of B & F) produce a putrefactive smell and digest meat

Non-proteolytic botulinum toxins (E and some of B, C, D, & F) do not produce a smell so go undiscovered if they are in your food

Question 15

Which botulinum toxin types affect humans?

Answer 15

Humans: A, B, E, and (rarely) F. Type F is associated with contaminated fish

Animals: C & D

None: G

Question 16

Why is it recommended not to give honey to children under 1 year old?

Answer 16

It is hard to treat this food for botulism (heat to 85C for more than 5 minutes)

Children under 1 year (particularly < 6 months) are more at risk for infant botulism because they lack proper protective mechanisms

Question 17

How can heat be used to destroy botulism toxin?

Answer 17

Toxin can be easily destroyed by heating food to 85C for more than 5 minutes

Question 18

What type of bacteria is Clostridium botulinum?

Answer 18

Large, Gram positive, rod-shaped (bacilli), motile, obligate anaerobe (oxygen is poisonous to cell) that forms spores

Question 19

When do bacteria form spores and where are C. botulinum spores found?

Answer 19

Spores are formed when bacteria are under stress

C. botulinum spores are found in the soil and in silt (sediment of streams/lakes/coastal waters). Spores can live for many years

Question 20

When does Clostridium botulinum produce botulinum toxin?

Answer 20

Toxin is produced in favourable conditions: warm temperature, moisture, protein source, anaerobic environment. Spores become active and produce toxin

Spores can produce toxin but conditions needed for this (anaerobic, low-salt, -sugar, -acid environment at ambient temperatures) are rarely obtained. This means botulism is uncommon

Question 21

How many toxin types do C. botulinum normally produce?

Answer 21

Usually, bacteria only produce one toxin type

However bacteria that produce multiple have been reported. These are donated like: Bf, where type B toxin was found in excess of type F

Question 22

What are the symptoms of botulism?

Answer 22

Flaccid paralysis

Blurred/double vision
Ptosis (drooping eyelid)
Nausea, vomiting, diarrhoea and/or constipation
Cramps
Respiratory difficulty

Question 23

What is the usual direction of spread of paralysis in botulism cases?

Answer 23

Paralysis typically starts in the facial muscles and then spreads to the limbs.

In severe forms, paralysis reaches respiratory muscles which results in respiratory failure and death.