VMC 311: Systematic Veterinary Bacteriology and Mycology (2+1)

DIAGNOSIS

Direct microscopy

• Demonstration of characteristic drumstick spores of C.tetani by Gram stained smears of material from a wound (but it is not confirmative, because C.tetanomorphum and C.tetanoides also produce drumstick spores).

Isolation

• Necrotic tissue from a wound or wound exudates can be heated to 80⁰C for 20mts and used to inoculate a blood agar plate and another blood agar plate containing stiff agar.
• A tube of thioglycollate medium or cooked meat broth could also be inoculated and sub cultured into blood agar.
• The plates are to be incubated anaerobically for 2-3 days. Growth is noticed using a hand lens as a filamentous growth spreading through out the medium.
• The edges of this growth give pure culture on sub cultivation.
• Confirmation is done by identification of toxin.
• The toxin present in animal’s serum or in filtrate from cooked meat broth or thioglycolate medium can be inoculated in to mice S/C or I/M-ly and identified by neutralization or protection tests using specific antitoxin.