Micro| Yersinia Species

3.23 Yersinia Species Microbiology review for the USMLE Step 1 Exam Yersinia are gram-negative, non-motile bacteria that cause zoonotic diseases. Yersinia produce urease enzyme to survive in the stomach and are facultative intracellular bugs. Three species of yersinia causing disease in humans are Yersinia pestis, Yersinia enterocolitica, and Yersinia pseudotuberculosis. The Yersinia species inhibit phagocytosis, the capsule contains F1 and V proteins and the injectosome injects Yersinia outer proteins. Yersinia pestis spreads through fleas, causing bubonic, pneumonic, or septicemic plague with symptoms like fever, chills, and swollen lymph nodes. Yersinia enterocolitica is spread through contaminated food or dog feces, causing enteric infection, and symptoms like diarrhea, abdominal pain, and vomiting. Yersinia pseudotuberculosis causes enteric disease, similar to Y. enterocolitica, and granulomatous lesions that look like tuberculosis. Yersinia pestis is rare with 500 cases reported since 1970, compared to Y. enterocolitica, which causes 100,000 cases each year