Yersinia pestis

Gram-negative bacillus that exhibits bipolar staining ("safety pin" appearance)
Colonies have typical "fried-egg" appearance
Transmitted by Xenopsylla cheopis, the Oriental rat flea
Treatment is with gentamicin, streptomycin, doxycycline, ciprofloxacin, TMP-SMX, chloramphenicol
- Beta-lactam antibiotics may appear effective in vitro but are not reliable in vivo