Y. pestis on SBA 48h image courtesy of CDC
Y. pestis "fried egg" on SBA at 72h image courtesy of CDC
Culture Characteristics:
- Growth at 22-25oC and at 35oC
- Organism prefers 25oC, so the colonies will grow faster at this temperature
- Growth occurs on most routine media, including sheep blood agar (SBA), chocolate agar (CHOC), MacConkey (MAC) agar, and routine blood culture media
- Non-lactose fermenter on MAC agar
- Growth is slower than other Enterobacteriaceae
Colony Morphology on SBA at 35oC:
- At 24 hours, colonies are pinpoint and translucent with a gray-white color
- Colonies take on a yellow tint as they age, after 48-72 hours, referred to as a "hammered copper" appearance
- An irregular or "fried egg" appearance, shown in the lower image, can also be seen at 48-72 hours
Characeristic Features:
- Growth at 22-25oC is a hallmark feature of this organism
