The page below is a sample from the LabCE course Preliminary Identification of the Primary Select Agents of Bioterrorism. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Preliminary Identification of the Primary Select Agents of Bioterrorism (online CE course) »
How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 97 CE courses, most popular
$95 Add to cart
Pick Your Courses
Up to 8 CE hours
$50 Add to cart
Individual course$20 Add to cart

B. anthracis image courtesy of CDC

Bacillus anthracis

Clinical specimens where organism may be encountered:

  • CSF
  • Blood
  • Stool (rare)
  • Vesicle fluid, skin swab, or biopsy

Gram stain morphology from clinical specimens:

  • Large, gram-positive rods with square or concave ends in short chains
  • Spores are usually NOT present
  • Capsule may be viewed in smears from infected tissue, but this is NOT reliable

Gram stain morphology from culture material:

  • Large, gram-positive rods with square or concave ends, often in long chains (more than 2-4 cells)
  • Cells easily decolorize as the culture ages
  • Does NOT form capsules in culture
  • Central to sub-terminal, oval spores, with NO significant swelling of the cell

It must be noted that spore production increases with the age of the culture. Do NOT keep these cultures in the laboratory for longer than 24 hours for this reason!