6. bacillus athracis

MICROORGANISM

1. RATHEESH R.L bacillus

2. It is generally classified as -GRAM POSITIVE BACILLI -GRAM NEGATIVE BACILLI

3. GRAM POSITIVE BACILLI BACILLUS CORNEY BACTERIUM CLOSTRIDIUM MYCOBACTERIUM

4. GRAM NEGATIVE BACILLI IT INCLUDES ENTEROBACTERIA FAMILY AND VIBRIOS

5. GRAM POSITIVE BACILLI BACILLUS The medically important species is BACILLUS ANTHRACIS

6. MORPHOLOGY It’s aerobic G + ve , non motile and non spore forming. Size varies from 4-8 to 1-1.5mm They may be arranged in singles or in pairs or in short chains.

7. CULTURAL CHARACTERISTICS They are aerobic and facilitative anaerobic, grow optimum at the temperature of 37 degree C, and PH 7.75

8. NUTRIENT AGAR MEDIUM colonies will be formed which are irregualar , round, grayish white colour , froasred glass appearance measuring 2-3 mm in diameter. under microscope the edges of colonies will show tangled mass of long hair like curls, so it is called MEDUSA HEAD

9. NUTRIENT BROTH It shows floccular turbidity or no turbidity

10. BLOOD AGAR MEDIUM NO HEMOLYSIS WILL OCCUR

11. GELATIN STAB CULTURE INVERTED FIT TREE APPEARANCE WILL OCCUR

12. PATHOGENESIS Anthrax is primarily a disease of domesticated and wild animals, particularly herbivorous animals, such as cattle, sheep, horses, and goats. Humans become infected incidentally when brought into contact with diseased animals, which includes their flesh, bones, hides, hair and excrement.

13. The most common form of the disease in humans is  cutaneous anthrax , which is usually acquired via injured skin or mucous membranes. A minor scratch or abrasion, usually on an exposed area of the face or neck or arms, is inoculated by spores from the soil or a contaminated animal.

14. The spores germinate, vegetative cells multiply, and a characteristic  gelatinous edema develops at the site. This develops into  papule  within 12-36 hours after infection. The papule changes rapidly to a  vesicle , then a pustule  (malignant pustule ), and finally into a  necrotic ulcer  from which infection may disseminate, giving rise to  septicemia .

15. Another form of the disease,  inhalation / pulmonary anthrax  ( woolsorters ' disease), results most commonly from inhalation of spore-containing dust where animal hair or hides are being handled. The disease begins abruptly with high fever and chest pain.

16. Gastrointestinal anthrax  : Intestinal anthrax results from the ingestion of poorly cooked meat from infected animals. Gastrointestinal anthrax is rare but may occur as explosive outbreaks associated with ingestion of infected animals. It is manifested by diarrhea and malena  

17. LABORATORY DIAGNOSIS It mainly includes 1. hematological investigations and 2. bacteriological investigations

18. HEMATOLOGICAL INVESTIGATIONS It shows an increase in the leucocyte count.

19. BACTERIOLOGICAL INVESTIGATIONS The specimen is collected depending upon the nature of infection. Swabs, pus from pustules, blood in septicemia, sputum in pulmonary anthrax, gastric aspirates, feces or food in intestinal anthrax.

20. MICROSCOPY After gram staining under microscope it shows gram positive bacilli in chains When the blood films are stained with polychrome methylene blue for 5-10 seconds , it shows a purplish material around the bacilli. It is a characteristic feature of B.anthracis and is known as Mc Fadyean’s reaction.

21. CULTURE The specimen is inoculated in nutrient agar medium or blood agar medium at 37 degree C for 12-24 hrs , medusa head colonies will appear. Gelatin stab culture: shows inverted fit tree appearance

22. BIO CHEMICAL TESTS 1. SUGAR FERMENTATION TEST: PRODUCTION OF ACID ONLY 2. CATALASE TEST: POSITIVE 3. NITRATE REDUCTION TEST : POSITIVE 4. GELATIN LIQUEFACTION TEST: POSITIVE

23. ANIMAL INOCULATION TEST In this test a small amount of exudate is injected s/c into the guinea pig or mouse. The animal dies within 40-72 hrs shows the presence of B.anthracis .

24. SEROLOGICAL TESTS Infected tissue is washed with saline and boiled for 5minutes and filtered. The filtrate is layered over anthrax anti-serum in a narrow test tube If the filtrate contains anthrax antigen, a ring appearance will occur in the test tube.

25. TREATMENT The drug includes Penicillin Ciprofloxacin Streptomycin tetracycline

26. VACCINES Salvo’s immune serum is used in serious toxic cases Cell free vaccine used in high risk groups Non-living vaccine is using among agricultural workers.