1. Bacillus Balsam Miri

2. Bacillus species are large, Gram-positive, endospore-forming rods
Bacillus species are large, Gram-positive, endospore-forming rods. They are catalase positive, aerobic or facultative anaerobic and motile with the exception of B. anthracis and B.mycoides. Bacillus includes both free-living and pathogenic species. Under stressful environmental conditions, the cells produce oval endospores that can stay dormant for extended periods,The spore is a dehydrated cell with thick walls and additional layers that form inside the cell membrane. It can remain inactive for many years, but if it comes into a favorable environment, it begins to grow again.

3. Two Bacillus species are considered medically significant: B
Two Bacillus species are considered medically significant: B. anthracis, which causes anthrax, and B. cereus, which causes a foodborne illness

5. Bacillus anthracis Genome structure
B. anthracis has a single chromosome which is a circular, It also has two circular, extrachromosomal, double-stranded DNA plasmids, pXO1 and pXO2. Both the pXO1 and pXO2 plasmids are required for full virulence

6. pXO1 plasmid
The pXO1 plasmid contains the genes that encode for the anthrax toxin components: (protective antigen, PA), (lethal factor, LF), and (edema factor, EF).

7. pXO2 plasmid
pXO2 encodes the synthesizes polyglutamate capsule. This capsule allows B. anthracis to evade the host immune system by protecting itself from phagocytosis.

8. Manifestations in human disease
Three forms of human anthrax disease are recognized based on their portal of entry.
Cutaneous, the most common form (95%), causes a localized, inflammatory, black, necrotic lesion (eschar).
Pulmonary, the highly fatal form, is characterized by sudden, massive chest edema followed by cardiovascular shock.
Gastrointestinal, a rare but also fatal (causes death to 25%) type, results from ingestion of spores.

11. Natural habitat
Most of the bacillus species are saprophytes widely distributed in air, soil and water. B. anthracis endospores can survive in soil for up to 50 years. It is thought that incubator areas exist where, for short periods, germination of spores and multiplication of vegetative cells can occur. These areas have a warm climate and alkaline soil.

12. Growth characteristics
B. anthracis a facultative anaerobe, grows on common media between 15C and 40C. Colonies grown in air have a dull surface and wavy margin formed by strands of bacterial chains (medusa-head) Cells are nonencapsulated. Sporulation occurs under abundant oxygen and never in vivo. Organisms in infected tissue exposed to air sporulate after several hours.

14. Resistance
Vegetative cells in unopened carcasses may survive for up 1-2 weeks, but spores can persist decades in a stable, dry environment. Spores are killed by autoclaving (121 C/15 min) and dry heat (150 C/60 min), but not by boiling for less than 10 min. They are not highly susceptible to phenolic, alcoholic disinfectants. Heat fixation of smears does not kill spores.

15. Transmission
Infection takes place by ingestion of contaminated feed or water or via wound infection and insect bites. Human infection occur via skin wounds, inhalation (wool-sorter ,s disease) and ingestion.

16. Pathogenicity and Pathogenesis
The majority of Bacillus species have little or no pathogenic effect. Some specie causes disease in insects such as B. larvae. B. anthracis is the major animal pathogen in the genus, the cause of anthrax in both animals and human. B. cereus produces food poisoning in man and rare infection in animals. B.licheniformis has been reported as causing abortion in cattle and sheep

17. Pathogenicity and Pathogenesis
B. anthracis toxin is leucocidal, increase vascular permeability and produces capillary thrombosis causing shock. The polypeptide capsule is antiphagocytic. To be fully virulent, B. anthracis must produce both the toxin and capsule.
Anthrax can occur in virtually all mammalian species but birds are highly resistant. Cattle, sheep and goats are most susceptible to infection, horses and humans occupy an intermediate position, while pigs and carnivores are comparatively resistant.

18. Pathogenicity and Pathogenesis
Anthrax is a peracute disease in cattle and sheep, characterized by septicemia and sudden death. Postmortem finding include exudation of tarry blood from body orifice, failure of blood to clot, incomplete rigor mortis and splenomegaly in cattle. In the less susceptible animals inflammatory edema of face, throat and neck is a common finding and colic in horses.
B. cereus produces an enterotoxin that is responsible for food poisoning in man.

20. Laboratory Diagnosis Specimens
A postmortem examination is usually unnecessary and should never be carried out unless the carcass can be taken to a place where, subsequently, the surrounding area can be decontaminated. Endospores are not formed in the animal body but sporulation is triggered when vegetative cells are exposed to air, as happens during necropsy. If anthrax is suspected in cattle or sheep, thin blood smears should be made from blood taken from ear or tail vein. In horses and pigs edematous fluid can be collected from localized sites. If the carcass has been opened, spleen material may be collected.

21. Direct Examination
B. anthracis produce a capsule in vivo and either Giemsa or polychrome methylene blue stains are used to demonstrate the capsule which is of diagnostic importance. Polychrome methylene blue – stained smears reveal square-ended, blue rods in short chains surrounded by pink capsular material. The capsule is red in Giemsa-stained smear .

22. Treatment
Bacillus anthracis is susceptible to penicillin, chloramphenicol, streptomycin,tetracycline and erythromycin. Treatment should continue for at least 5 days. In acute anthrax, antimicrobial treatment is often unsuccessful.

23. Bacillus cereus
B.Cereus can cause opportunistic infections, most abortion and bovine mastitis In human, B. cereus is responsible for several forms of food poisoning manifested by diarrhea or vomiting.

24. Comparsion Generally motile Nonmotile Noncapsulated Capsulated
bacillus anthrasis
Other bacilli
Generally motile
Noncapsulated
Grow in short chains
Not present
Hemolysis well marked
Rapid liquefaction 
Usually grows
Nonmotile
Capsulated
Grow in long chains
Medusa head colony
Weak or no hemolysis
slow gelati liquefaction
No growth at 45C◦