Shigella

• What does the red sunset in the image represent?

  Shigella is gram-negative
• How does Shigella appear under a microscope?

  Pink or red and rod-shaped
• What type of secretion system does Shigella utilize?

  Type 3 secretion system
• How is Shigella transmitted between humans?

  Human to human transmission
• Through which cells does Shigella invade the gastrointestinal tract?

  M cells in Peyer's patches
• What do the reins in the image represent?

  Host's actin filaments
• What is the immune response to Shigella primarily composed of?

  Neutrophils
• Why is Shigella considered immobile?

  It lacks a flagellum
• What toxin does Shigella produce?

  Shigatoxin
• What does Shigatoxin inhibit?

  60S ribosomal subunit
• What condition is associated with Shigella's toxin?

  Hemolytic uremic syndrome
• What are the four unique findings of hemolytic uremic syndrome?

  Thrombocytopenia, hemolytic anemia, schistocyte formation, uremia
• What does von Willebrand factor assist with?

  Hemostasis by binding to damaged endothelium
• What happens to von Willebrand factor in hemolytic uremic syndrome?

  It cannot be degraded into monomers
• What is the result of abnormal platelet adhesion in hemolytic uremic syndrome?

  Formation of microthrombi
• What are schistocytes?

  Partially lysed red blood cells
• What are the four species of Shigella to know for Step 1?

  1. Shigella dysenteriae (most severe)
  2. Shigella flexneri
  3. Shigella boydii
  4. Shigella sonnei (least severe)
• What are the treatment options for Shigella?

  • Ampicillin
  • Fluoroquinolones
  • Trimethoprim-sulfamethoxazole
  • Ceftriaxone
• Why is Shigella considered acid resistant?

  It is not inactivated by gastric acid
• What does the term "low inoculum" refer to in the context of Shigella?

  Few pathogens needed to cause infection
• What is the significance of the raspberry patches in the image?

  They represent Peyer's patches
• What does the term "dysentery" refer to in relation to Shigella?

  Damage to the GI mucosa causing bloody diarrhea
• What is the role of actin filaments in Shigella's movement?

  They allow intracellular movement
• What does the term "gram-negative" indicate about Shigella?

  It has a thin peptidoglycan layer
• How does the presence of blood in stool relate to Shigella infection?

  Indicates damage to the intestinal lining
• What is the significance of the handcuffed man in the image?

  Represents Shigella's immobility outside the host
• What is the role of the police officers in the image?

  They inhibit the camera crew, representing toxin action
• What is the primary method of diagnosing Shigella infection?

  Stool culture
• How does Shigella's acid resistance affect its infection capability?

  It allows survival in gastric acid
• What does the term "bloody diarrhea" indicate in a clinical context?

  Presence of blood in stool
• What does the term "dysentery" specifically refer to?

  Severe diarrhea with blood and mucus
• How does the presence of neutrophils relate to Shigella infection?

  Indicates an immune response to infection
• What does the term "Peyer's patches" refer to?

  Aggregates of lymphoid tissue in the intestine
• How does the clinical vignette illustrate Shigella's characteristics?

  It highlights bloody diarrhea and low inoculum
• What does the term "gram-negative bacillus" indicate about Shigella?

  It is a rod-shaped, gram-negative bacterium
• What is the significance of the amp in the image?

  Represents treatment with ampicillin
• What does the term "trimethoprim-sulfamethoxazole" refer to?

  A treatment option for Shigella
• How does the presence of a trident relate to Shigella treatment?

  Represents ceftriaxone as a treatment
• What does the term "non-lactose fermenting" indicate about Shigella?

  It does not ferment lactose
• What does the term "invasive organism" imply in the context of Shigella?

  It can penetrate host cells