clostridium botulinum

botulism

(a) food-borne botulism

- spores wide spread in soil,contaminate vegetables and meat.

-when these fooa are canned without adequate sterilization, spores survive and germinate in the aerobic environment

- toxin is produced within the canned food and ingested preformed

- the highest-riskfoods are vegetables such as green beans and mushrooms, smoked and salted fish, commercially canned salmon

- toxin is activated by proteases in the gastric fluid and by gastric acidity

- toxin is absorbed in the intestineand is transported systemically via the bloodstream to reach the peripheral neuromuscular synapses

-toxin bind to the neurone

- it prevents the release of Ach across the synaptic cleft

- thus it produce paralysis of the motor system

- botulinum toxin is quick acting

- ip short 12hours

- once fixed it actions is very difficult to reverse with antitoxin treatment

- 1ry symptoms is weakness of flaccid paralysis.

- the cranial nerve are affected first ( blurred vision, inabiity to swallow, difficulty in speech)

- followed by a descending, symmetric paralysis of motornerves

- nausea and vomiting are not usuall prominent

- no fever is apparent

- death is caused by resp failure

(b) infant botulism

-result from germination of spores in the gastrointest tract

- occurs in infants between 2 weeks and 6 months of age

- the disease is characterized by constipation and weak sucking ability and generalized weakness

- almost all cases of the disease recover.