Bacterium
Yersinia pestis
Flea-borne plague, safety-pin bipolar rod
yer-SIN-ee-uh PES-tis
High-yield clue
Bipolar 'safety-pin' staining coccobacillus spread by rat fleas, causing swollen tender lymph node (bubo) vocabulary.
Overview
A Gram-negative coccobacillus that causes plague, transmitted by rodent fleas; a high-yield zoonotic and select-agent study organism with a classic bipolar staining look.
Classification
- Gram-negative
- Coccobacillus
- Enterobacterales
- Facultative anaerobe
- Non-motile
Lab & identification clues
- Bipolar 'safety-pin' staining with Giemsa/Wayson vocabulary
- F1 capsular antigen concept
- Slow-growing on standard media note
- Yop virulence protein vocabulary
Associations
- Oriental rat flea (Xenopsylla) vector vocabulary
- Bubonic, septicemic, and pneumonic form vocabulary
- Rodent reservoir and Category A agent framing
Commonly confused with
- Yersinia enterocolitica
- Francisella tularensis
Your notes
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.