Bacillus

Bacillus

General Characters of Bacillus spp

- It is large Gram positive bacilli measuring 1 × 3–4µm, aerobic, spore forming outside the host.
- It is found in soil habitat, spores produced when bacteria are stressed such as drying conditions, unfavorable temperatures.
-Most aerobic spore-forming species are easily isolated and readily grown in the bacteriology laboratory. It is grow at 37C. The majority are mesophiles, with temperature optima between 30 and 45 degrees. They are found growing over a range of pH from 2 to 11.

. Laboratory identification of Bacillus Spp
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Bacillus spp.











The colony of Bacillus spp.

Spore staining

By spore staining technique (Malachite green & safranin) , the spore appears green while the vegetative cells appear red.










s Laboratory identification of B. anthraci

a. Gram stain-large, square-ended, gram-positive in singles or chains, has central spores.
Non-motile. -
- Presence of capsule, capsule appear as clear areas within bacterial cell on gram stain
- Stain bacteria with polychrome methylene blue (M Fadyean s stain) and examined for the characteristic square-ended, blue-black bacilli surrounded by a pink capsule.
b. Colony morphology – non-hemolytic, large, gray to white colonies with a rough texture.