YERSINIA
Definition
- Yersinia is a genus of Gram-negative, facultative anaerobic bacteria.
- They are non-motile, capsulated bacteria.
- They can cause disease in animals and humans.
Causes
- Yersinia pestis is the causative agent of plague.
- Yersinia enterocolitica causes enteric fever.
- Yersinia pseudotuberculosis causes pseudotuberculosis.
Types
- Yersinia pestis
- Yersinia enterocolitica
- Yersinia pseudotuberculosis
- Yersinia intermedia
- Yersinia frederiksenii
Pathogenesis → Yersinia pestis: → Ingestion of infected fleas or direct contact with infected animals. → Bacteria enters the host through a wound or bite. → Bacteria multiply in regional lymph nodes. → Bacteria enter the bloodstream and cause septicemia. → → Yersinia pestis → → Septicemia → → Black Death (bubonic plague)
→ Yersinia enterocolitica: → Ingestion of contaminated food or water. → Bacteria enter the host through the gastrointestinal tract. → Bacteria multiply in the small intestine. → Bacteria cause inflammation and damage to the small intestine.
Morphology
- Yersinia bacteria are Gram-negative and non-motile.
- They are capsulated and have a characteristic L-form shape.
Clinical Features
- Yersinia pestis: → Bubonic plague: Swollen lymph nodes (buboes), fever, chills, and weakness. → Pneumonic plague: Fever, cough, and difficulty breathing. → Septicemic plague: Fever, chills, and organ failure.
- Yersinia enterocolitica: → Diarrhea, abdominal pain, and fever. → Inflammation and damage to the small intestine.
- Yersinia pseudotuberculosis: → Inflammation and damage to the small intestine. → Diarrhea, abdominal pain, and fever.
Complications
- Yersinia pestis: → Black Death (bubonic plague) → Pneumonic plague → Septicemic plague
- Yersinia enterocolitica: → Intestinal perforation → Perforation of the intestinal wall
- Yersinia pseudotuberculosis: → Intestinal perforation → Perforation of the intestinal wall
Diagnosis
- Culture of the bacteria from blood, lymph nodes, or intestinal tissue.
- Serological tests (ELISA, IFA)
- PCR (Polymerase Chain Reaction)
Management
- Antibiotics (streptomycin, gentamicin, ciprofloxacin)
- Supportive care (fluid replacement, oxygen therapy)
- Surgical drainage of infected lymph nodes or intestinal tissue.
Memory Trick "Yersinia causes plague and pain, Infecting animals and humans in vain. Enter the host through bites or wounds, Multiply in lymph nodes, then cause profound sounds."