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NC Department of Health and Human Services
State Laboratory of Public Health
N.C. Public Health Home

Bioterrorism - Agents of Concern

Yersinia pestis

Yersinia Pestis Colonies

Colony Characteristics

  • Grows well on most non-selective standard lab media.
  • Pinpoint gray/white, non-hemolytic at 24 hours. Typical enteric colony growth by 48 hours. After 48 hours appears gray/white and yellow with a "fried egg" appearance.
  • Appears as small non-lactose fermenting colonies on MacConkey agar.
  • In enriched broth such as BHI, undisturbed growth appears flocculent.
Petis on Horse Blood Agar 48hrs
Y. pestis on Horse Blood Agar @48 hrs
Petis on Horse Blood Agar 72hours
Y. pestis on Horse Blood Agar @72 hrs
Petis on Sheep Blood Agar 48hours
Y. pestis on Sheep Blood Agar @48 hrs
Petis on MacConkey 72 hours
Y. pestis on MacConkey Blood Agar @72 hrs


Yersinia Pestis Microscopic

  • Plump gram negative rod.
  • Commonly displays bipolar staining resembling safety pins.

Oxidase Negative
Non-Motile at Room Temperature
Catalase Positive

Any sample that cannot be ruled out by these methods should be forwarded to the NCSLPH.

SLPH Bioterrorism Information