yersenia_flashcards
What are the key species of Yersinia?
Yersinia pestis (plague), Yersinia enterocolitica (gastroenteritis), Yersinia pseudotuberculosis (intestinal infections).
Describe the morphology and gram-staining characteristics of Yersinia.
Gram-negative coccobacilli with a safety-pin appearance under certain stains like Giemsa or Wayson.
How is Yersinia pestis transmitted?
Flea bites from infected rodents or respiratory droplets in pneumonic cases.
What are the common transmission routes for Yersinia enterocolitica and Yersinia pseudotuberculosis?
Ingestion of contaminated food and water, particularly undercooked pork and unpasteurized dairy products.
What is the significance of the Type III Secretion System (T3SS) in Yersinia?
Allows the bacteria to inject virulence factors into host cells, disrupting immune responses.
What is the function of the capsule in Yersinia pestis?
Helps evade the immune system by preventing phagocytosis by immune cells.
List the plasmids found in Yersinia and their functions.
pCD1 for T3SS, pMT1 for flea transmission, Pla protease for immune evasion.
What role do Yersinia outer proteins (Yops) play in infection?
Injected via the T3SS, they disrupt host cell signaling and immune responses.
What is molecular mimicry in Yersinia?
Alters lipopolysaccharides (LOS) to resemble host molecules, evading immune detection.
What are the three clinical forms of plague caused by Yersinia pestis?
Bubonic plague (swollen lymph nodes), pneumonic plague (respiratory symptoms), septicemic plague (systemic infection).
What are the common symptoms of Yersinia enterocolitica infection?
Diarrhea (sometimes bloody), abdominal pain, fever; can mimic appendicitis.
What complication can arise post-Yersinia infection in some patients?
Reactive arthritis or erythema nodosum.
What diagnostic methods are used to detect Yersinia infections?
Stool or blood culture, PCR, microscopy (safety pin appearance), serological tests.
What antibiotics are used to treat Yersinia pestis infections?
Streptomycin, doxycycline, ciprofloxacin, gentamicin.
What public health measures help prevent Yersinia infections?
Rodent and flea control, food safety (cooking pork, pasteurizing dairy), isolation for pneumonic cases.
