A bacterium which causes plague.
Organism of Oriental plague, carried by rats, and thence transferred to man by bite of rat flea, resulting in bubonic, septicaemic, or pneumonic plague (the latter communicable also by droplet infection). Bubo pus, blood or sputum cultures show the characteristic bipolar stained rods, and first isolation is best at 30°C; the organism is non-motile, and highly virulent to laboratory animals. Good MacConkey growth, not urease producing.