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Salmonella typhi

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Salmonella typhi 

  •  Virulence factors
    • Encapsulated with Vi polysaccharide
      • Provides resistance against phagocytosis 
      • Vi polysaccharide is targeted by vaccine
    • Endotoxin
  • Transmission
    • Fecal-oral (contaminated food or water)
      • Usually seen in travelers to developing countries/endemic regions
    • Reservoir is humans only (no animals)
      • Carriers have gallbladder colonization
  • Presentation - Typhoid fever
    • Escalating fever lasting several days
    • Initial constipation, followed by pea-soup watery diarrhea
      • Also presents with abdominal pain
      • May be eventually complicated with GI bleeding/hemorrhagic enteritis (due to ulceration of Peyer’s patches) with possible bowel perforation
      • Contrast w Shigella - bloody diarrhea (inflammatory)
    • Rose spots on chest/abdomen
      • several faint, erythematous maculopapular lesions on the chest and abdomen
    • Associated with osteomyelitis in sickle cell patients
  • Treatment
    • Fluoroquinolone
      • Fluoroquinolones are first-line for all patients 
      • Azithromycin if resistance or intolerance of fluoroquinolones 
      • Antibiotics may prolong duration of fecal excretion
  • Prevention
    • Oral vaccine contains live-attenuated S typhi
    • IM vaccine contains Vi capsular polysaccharide
    • Vaccination recommended prior to traveling to endemic areas