Salmonella species


Enterobacteriaceae  (Gram Negative Bacilli)  
>Citrobacter species:
     1] Citrobacter koseri
     2] Citrobacter freundii
>Enterobacter species
     1] Enterobacter cloacae,
     2] Enterobacter aerogenes)
>Escherichia coli
>Klebsiella species:
     1] Klebsiella ozaenae
     2] Klebsiella pneumoniae
     3] Klebsiella rhinoscleromatis
>Morganella species 
     1] (Morganella morganii)
>Proteus species:
     1] Proteus mirabilis
     2] Proteus vulgaris
>Providencia species:
     1] Providencia_rettgeri
     2] Providencia stuartii
>Salmonella species: Led
     1] Salmonella enteritidis
     2] Salmonella typhi
     3] Other
>Serratia marcescens
>Shigella species:  
     1] Shigella dysenteriae (serogroup A)
     2] Shigella flexneri
     3] Shigella boydii
     4] Shigella sonnei
     5] Other


  • Rod-shaped, Gram-negative, facultative anaerobic, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella that grade in all directions. Most species produce hydrogen sulfide.
  • Salmonella (closely related to the Escherichia genus) cause illnesses such as typhoid fever, paratyphoid fever, and foodborne illness.
  • Salmonella infections are zoonotic and can be transferred between humans and nonhuman animals.
  • Many infections are due to ingestion of contaminated food. 
  • Salmonella typhi is adapted to humans and does not occur in other animals.
  • Currently, there are three recognized species:
    • S. enterica,
    • S. bongori and
    •  S. subterranean, with six main subspecies:
      • enterica (I),
      • salamae (II),
      • arizonae (IIIa),
      • diarizonae (IIIb),
      • houtenae (IV),
      • and indica (VI).
      • Historically, serotype (V) was bongori, which is now considered its own species.

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Important considerations:  The choice of an agent should be based on local antimicrobial sensitivities, site of infection, cost, and comorbid conditions.   Generally, the most common agents/regimens are listed first.   Listed dosages may need to be adjusted for renal dysfunction.  

  1. Ciprofloxacin 500-750 mg orally q12h or 400mg IV q12h
  2. Levofloxacin 500mg – 750 mg IV/PO once daily
  3. Bactrim DS (TMP-SMX) 160/800mg po bid
  4. Ceftriaxone 1-2 grams IV q24h 
  5. Highly-resistant strains: 
    • Imipenem 500mg IV every 6 hours [Range: 250-1000 mg q6-8h] or Meropenem 1 gram IV q8h
Salmonella species