Spore forming, G +ve aerobic bacilli

Spore forming, G +ve aerobic bacilli:

Bacillus species:

General characteristics and morphology:
The genus bacillus includes large aerobic, gram-positive rods occurring in chains. Most members of this genus are saprophytic organism prevalent in soil, water and air, and on vegetation, such as Bacillus cereus and Bacillus subtilis. Some are insect pathogens.
B. cereus can grow in foods and produce an enterotoxin and cause food poisoning.
B. anthracis which causes anthrax, is the principal pathogen of the genus.
This genus form heat-resistant spores, chemical disinfected and UV-light, and it can be killed by exposing to moist heat and at 121?C for 20 min. and 1 hr. in 160?C dry heat. The spores are found in air, soil and water. They are straight bacilli with round or square ends producing endospore, centrally located in non motile spp. and of the same width of bacillus body.
B. anthracis are non motile, non hemolytic arranged in chains (Streptobacilli) encapsulated.
B. subtilis are motile, hemolytic, spore can survive 50 years in soil.
Bacillus anthracis:
This causative organisms of anthrax in cattle, sheep and other animals, it is infected for man, generally by spore entering through injured skin causing cotaneous anthrax or by inhalation of spores causing pulmonary anthrax from infected animal or intestinal anthrax which is rare and cause when man eat the meat of animals dying by anthrax.
1. Morphology:
G +ve, anarerobic, large arranged in filamentous chain, but may form single or in pairs in animal blood, it forms spores, non motile, surrounded by irregular capsule when stained by polychrome.
Methelin blue (McFadyeans reaction) ? methylen blue (cell), Capsule ? red color.
2. Culture characteristics:
Aerobic, temp. range for growth from 15-45?C at 37?C, grow on ordinary nutrient agar colonies are irregular round, 2-3 mm in diameter, grayish and give the medusa head appearance, colonies on blood are non-hemolytic, stabbing semi solid medium showing non-motile bacteria, whereas related non pathogenic spp. are motile by swarming B. subtilis.