A short note on botulism

Cl.botulinum

Ø  Causes  botulism( Sausage poisoning/fatty poisoning)

Ø  A paralytic disease mainly through food poisoning

MORPHOLOGY

·        Gm+  ve rod shape bacteria

·        Non capsulated

·        Motile  by peritrichous flagella

·        Produce spores

CULTURAL CHARACTERS

§  Strict anaerobe

§  Optimum temperature  for growth is 35 oC

§  Shows good growth in ordinary media

§  Sporulate better in alkaline glucose  gelatin media at  20-25 C .

RESISTANCE

·        Spores are  heat    resistant   and     radiation  resistant   .

 CLASSIFICATION

·        Cl.botulinum are classified into 8 types on  basis  of immunological difference in toxins .

·        C2  -cytotoxin

·        Others  produce  neurotoxin, powerful exotoxin.

FEATURES OF EXOTOXIN

·        It is not released during life time of organism and appears in medium only the

 death or autolysis of cell.

·        It is produced intracellularly

·        It is initially synthesized as inactive form. Enzymes such as trypsin convert it into active form

·        Toxin isolated as pure crystalline protein with molecular weight  70,000 Daltons

·        It is neuro toxin

·        Stable  toxin

·        Toxin  can be inactivated  at 80 o C for 30- 40 min  100o C for 10mins

·        Toxn resist digestion

·        It is absorbed through small intestine in active form .

·        It blocks  the release of  acetylcholine at synapse and  neuro muscular junctions .

Symptoms

·        Diplopia

·        Dysphagia  

·        Dysarthria                   

·        Decending paralysis  which may end in death by respiratory paralysis 

Pathogenecity 

There are three types of botulism: Food borne botulism, Wound botulism, Infant botulism

Food borne botulism occur due to ingestion of food containing toxin. Main sources are meat products, fish, canned food. Human disease caused by types A,B,E,F

Features include vomiting, thirst, constipation, coma which may lead to death within 1-7 days after the onset of disease.

Wound botulism is caused by type A, which may result from wound infection.

Infant botulism occurs to infants below 6 months. Manifestations include weakness, poor feeding,  pooled oral secretions

Lab diagnosis:

Specimen: food/feces                          

Include microscopy, animal inoculation, serological techniques

Propylaxis

Proper preservation of food

Proper canning

Vaccination          

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