Bacteremia is presence of bacteria in the blood, which is typically a sterile environment. This is distinct from sepsis, which is the body's response to the infection.

  • Primary bacteremia is the result of direct inoculation of bacteria into the bloodstream. Most commonly the result of IV drug use or contaminated venous catheters
  • Secondary bacteremia occurs when bacteria enters via an alternate site such as cuts in the skin, mucous membranes, or genitals

Risk Factors

Common Pathogens

Clinical Features

A host response may result in sepsis

  • Typically present with fever, chills and hypotension.
  • The presence of chills is also independently associated with blood stream infections

Alternatively bacteria may spread hematomagously to distant sites in body:

Differential Diagnosis



  • In gram positive bacteremia, more notably Staph aureus, consider sources from skin ulcerations, respiratory tract infections, IV drug use, and indwelling catheters
  • In gram negative bacteremia, common sources include respiratory tract and central venous catheters. In the elderly, consider urinary tract infections.

Blood Cultures

  • Obtain blood cultures prior to antibiotic therapy. Indicated for suspected bacterial infections or elevated white count.
  • Care should be taken to avoid contamination of samples with skin flora
  • If filling serial samples from same syringe, fill aerobic(blue) tube first to draw out air in the needle before filling the anaerobic(orange) tube



  • Uncomplicated MRSA with 14 days of IV vancomycin
  • Gram negative bacteremia should be treated via empirical therapy based on suspected source
  • Catheter associated infections
    • Short term catheters (<14 days) should be removed if cause of bacteremia, especially gram negative, staph aureus, enterococci, or mycobacteria
    • Long term catheters (>14 days) should be removed if patient is septic or bacteremia persists for 72+ hours


  • Extended spectrum beta lactam resistance - drugs of choice include those in the carbapenem family of antibiotics
  • Carbapenem resistance - usually requires a combination regimen of two or more


  • Admit

See Also

External Links