An Agar Diffusion Method for the Differentiation of Bacillus Anthracis,
Abstract
A method of differentiating Bacillus anthracis from B. cereus and other aerobic spore-formers has been developed based on detection of protective antigen production by individual colonies on solid medium. Single colonies were obtained by inoculating the surface of modified albimi agar with overnight nutrient broth cultures of the various test strains. After incubation at 37 C for 16 to 18 hours, discs of medium bearing individual colonies 3 to 5 mm in diameter were excised with a cork borer and transferred to matching holes in Ouchterlony plates precharged with equine anti-anthrax hyperimmune antiserum. The agar diffusion plates were observed after 24 and 48 hours' incubation at room temperature for precipitate lines that exhibited a Type I pattern of identity with a control preparation of protective antigen placed in an adjacent well. Positive results were obtained with all 14 strains of B. anthracis tested. Negative results were obtained with all tested strains of B. cereus, B. megaterium, B. subtilis, B. cereus var. mycoides, B. circulans, B. thuringiensis, B. polymyxa, B. sphaericus, and B. licheniformis. The growth medium, in addition to supporting elaboration of protective antigen, promoted encapsulation of the nine virulent anthrax strains and inhibited the growth of most of the strains of B. megaterium, B. subtilis, B. polymyxa, and B. sphaericus. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1969
- Accession Number
- AD0864433
Entities
People
- George G. Wright
- Lorell Angelety