9. clostridium tetani

MICROORGANISM

1. Ratheesh r.l CLOSTRIDIUM TETANI

2. morphology Gram positive, motile, Rod shaped, slightly curved bacilli measuring 2.5 X 0.4-0.5 mu m, occurring singly or in chains. Spores are presenting in the terminal part and gives a drum stick appearance.

3. Cultural characteristics They are anaerobic, growing maximum in the temperature of 37 degree C, at the pH of 7.4 They grow well in the ordinary media and the growth can be improved by adding serum or blood into this ordinary media.

4. Nutrient agar medium They produce swarming growth in this medium Colonies formed will be round, grayish-yellow color, transparent with granular surface. The size of colonies will be 2-5 mm in diameter.

5. Blood agar medium They produce a zone of alpha hemolysis around the colonies in the blood agar medium. Later it changes to beta hemolysis due to the presence of haemolysin .( Hemolysins   or haemolysins are lipids and proteins that cause lysis of red blood cells by destroying their cell membrane .)

6. Cooked meat medium The medium after incubation become turbid with gas formation. The meat is not digested, but turns to black color during prolonged incubation.

7. Lactose egg yolk medium No opalescence ( transmission of light through it) is produced in the medium.

8. pathogenicity C. tetani  affects humans by causing the disease called tetanus. The spores enter its host through open wounds, lacerations, or burns where many cells are dead. This provides the necessary environment for  C. tetani  to begin to spread to the human body. In the presence of anaerobic conditions (lacking oxygen), the spores can germinate. This is when the spores produce toxins that are harmful to the human nervous system.

9. The toxin tetanospasmin travels through the body via the nervous system, where its goal is to reach the spinal cord. Here is where the toxin really begins to attack the body. The toxin interferes with the neurotransmitters and, thus, blocks messages to the brain. This leads to unwanted muscle contractions and spasms, and in bad cases, individuals can experience severe seizures.

10. The clinical pattern of generalized tetanus consists of severe painful spasms and rigidity of the voluntary muscles. The characteristic symptom of "lockjaw" involves spasms of the masseter muscle. It is an early symptom which is followed by progressive rigidity and violent spasms of the trunk and limb muscles. Spasms of the pharyngeal muscles cause difficulty in swallowing. Death usually results from interference with the mechanics of respiration.

11. Earlier the masseter muscle are affected but as the spasm progresses to extensor muscles of the body, the body becomes arched in OPISTHOTONUS POSITION

12. LABORATORY DIAGNOSIS Hematological investigation no significant changes Bacteriological investigations 1.microscopy studies 2.culture studies 3.biochemical tests 4.animal inoculation test

13. microscopy studies Smears made from the wound swab, necrotic material from wound, pus or tissue from the wound. While gram staining it shows gram positive bacilli with drum stick appearance.

14. culture studies When the specimen is inoculated in the blood agar medium, the organism will produce large colonies after 1-2 days at 37 degree C of anaerobic incubation.

15. biochemical tests 1. Sugar fermentation test: positive 2 . Indole test: positive 3. H 2 S Production test: negative 4. Gelatin liquefication test: positive 5. MR & VP Test( Methyl Red and Voges-Proskauer Test Protocols ) : negative

16. animal inoculation test Two mice are selecting for the study One is protected with 1000 units of tetanus anti-toxin intraperitoneally 1 hr before the study and other one is unprotected. 0.2 ml of 2-10 days old cooked meat broth culture filtrate is injected S/C in the tail of the rats.

17. In positive cases the stiffness and spasm of tail develops in the test animal within 12-24 hrs and which subsequently spread to the body and death occurs in 1-2 days. However in control animal no changes will occur.

18. treatment Surgical methods include removal of dead, damaged or necrosed tissue, contaminated tissue, blood clots and foreign bodies from the wound. Antibiotics for the treatment includes penicillin and erythromycin

19. vaccines Active vaccines are TT and DPT Passive vaccine is anti-tetanus serum