Genus Shigella

Cards (30)

  • What is the Gram stain result for the genus Shigella?
    Gram -ve
  • What is the shape of Shigella bacteria?
    Rod shaped
  • What type of intracellular behavior does Shigella exhibit?
    Facultative Intracellular
  • Does Shigella ferment lactose?
    No, it is a non-lactose fermenter
  • How does Shigella respond to gastric acid?
    It is resistant to gastric acid
  • What is the motility characteristic of Shigella?
    Immotile
  • Why are stool samples for Shigella testing considered fastidious?
    They require prompt testing
  • What is the infectious dose required for Shigella due to its resistance?
    Low infectious dose required
  • What type of immune response is primarily involved with Shigella infection?
    PMN infiltration
  • What is the primary reservoir for Shigella?
    Colon
  • How is Shigella primarily transmitted?
    Faecal-Oral Route
  • What is another method of transmission for Shigella?
    Person-to-Person
  • What type of toxin does Shigella produce?
    Endotoxin
  • What is the mechanism of action of Shiga toxin?
    Inhibits 60S ribosomal subunit
  • What does Shiga toxin cause in enterocytes?
    Enterocyte damage and bloody diarrhoea
  • How does Shigella invade the intestinal tissue?
    It invades M cells in Peyer’s Patches
  • What process allows Shigella to move laterally within cells?
    Polymerises cell’s actin jet trails
  • What is the result of Shigella's evasion of the immune system?
    Shallow ulcers and bloody diarrhoea
  • How does the endotoxin trigger inflammation in Shigella infections?
    By using Type III secretion system
  • What is the clinical manifestation of Shigella infection?
    Shigellosis (bloody diarrhoea)
  • What is another clinical manifestation associated with Shigella?
    Reactive Arthritis
  • What serious condition can result from Shigella infection?
    Haemolytic Uremic Syndrome
  • What type of gastrointestinal condition is caused by Shigella?
    Bacterial Gastroenteritis
  • What specimens are used for microbiological diagnosis of Shigella?
    Faeces and Rectal Swabs
  • What microscopy technique is used for Shigella diagnosis?
    Non-specific methylene blue staining
  • What type of culture medium is used for Shigella?
    MacConkey Agar
  • What is the appearance of Shigella colonies on MacConkey Agar?
    Transparent non-coloured colonies
  • What is the appearance of Shigella colonies on Hektoen Agar?
    Blue-green colonies
  • What is the first-line treatment for Shigella infections?
    Fluoroquinolones e.g., ciprofloxacin
  • What is another treatment option for Shigella infections?
    3rd Generation Cephalosporins e.g., ceftriaxone