Clostridium botulinum Prepared by: Shiekha AL-Aujan

Clostridium botulinum Characters. Characters. Toxins. Toxins. Pathogenesis. Pathogenesis. Symptoms. Symptoms. Diagnostic laboratory test. Diagnostic laboratory test. Treatment. Treatment. Prevention. Prevention.

Characters A gram-positive, anaerobic bacilli. A gram-positive, anaerobic bacilli. Spore forming. Spore forming. Toxin forming. Toxin forming. Heat sensitive. Heat sensitive. Prefers low acid environment. Prefers low acid environment. Cause Botulism disease. Cause Botulism disease.

Toxins librated during growth. librated during growth. Seven types of toxins (A-G). Seven types of toxins (A-G). Antigenic (light and heavy chain). Antigenic (light and heavy chain). Environmental survival. (Inactivated by heat 100ºC for 20min ). Environmental survival. (Inactivated by heat 100ºC for 20min ). Most potential biological warfare agents. Most potential biological warfare agents. Lethal dose= 1-2  g. Lethal dose= 1-2  g.

Toxins Botulinum toxin is synthesized as a single polypeptide chain ( low potency). Botulinum toxin is synthesized as a single polypeptide chain ( low potency). The toxin is nicked by a bacterial protease (or by gastric proteases) to produce two chains : The toxin is nicked by a bacterial protease (or by gastric proteases) to produce two chains :  a light chain (the A fragment)  a heavy chain (the B fragment) connected by a disulfide bond. connected by a disulfide bond. The A fragment of the nicked toxin, becomes the most potent toxin found in nature The A fragment of the nicked toxin, becomes the most potent toxin found in nature

Active Toxin

Toxins Absorbed in GIT blood peripheral neuromuscular synapse. Absorbed in GIT blood peripheral neuromuscular synapse. Presynaptic block Acetylcholine release (by proteolysis of SNARE proteins in neuron which is important in Ach release) muscle paralysis. Presynaptic block Acetylcholine release (by proteolysis of SNARE proteins in neuron which is important in Ach release) muscle paralysis. SNARE proteins are synaptobrevin, SNAP- 25 and syntaxin. SNARE proteins are synaptobrevin, SNAP- 25 and syntaxin.

Pathogenesis transmitted in three ways: transmitted in three ways: Food or water toxin contamination. Food or water toxin contamination. Wound infected with C. Botulinum. Wound infected with C. Botulinum. Ingestion of C. botulinum. Ingestion of C. botulinum. Most common contaminated food: Vacuum packed, or canned alkaline food. Most common contaminated food: Vacuum packed, or canned alkaline food. E.g. fish, green beans, any home-canned food. E.g. fish, green beans, any home-canned food. Foods eaten without cooking. Foods eaten without cooking.

Pathogenesis of Infant Botulism Cause :infection by C. botulinum. Cause :infection by C. botulinum. Age: weeks of age. Age: weeks of age. Characterized by constipation and weak sucking. Characterized by constipation and weak sucking. It cause “sudden infant death syndrome- SIDS”. It cause “sudden infant death syndrome- SIDS”. found in the stool. found in the stool.

Symptoms appear in hrs. appear in hrs. include : include : Blurry vision, Double vision. Blurry vision, Double vision. Dry mouth. Dry mouth. Trouble swallowing. Trouble swallowing. Trouble breathing. Trouble breathing. Muscle weakness. Muscle weakness. Fever is not a symptom of botulism

Diagnostic laboratory test Toxins found in serum, leftover food. Toxins found in serum, leftover food. Mice injected with toxin die rapidly. Mice injected with toxin die rapidly. In infants, found in stool. In infants, found in stool. brain scan, spinal fluid examination, nerve conduction test. brain scan, spinal fluid examination, nerve conduction test.

Treatment Trivalent (A,B,E) antitoxin must administrated intravenously (recovery takes several weeks) Trivalent (A,B,E) antitoxin must administrated intravenously (recovery takes several weeks) Mechanical respirator is administrated if necessary. Mechanical respirator is administrated if necessary.

prevention Safe home canning. boiling the food for minutes before eating it. children less than 12 months old should not be fed honey ( can contain spores ).

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