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 useor contaminated venous catheters
- Secondary bacteremia occurs when bacteria enters via an alternate site such as cuts in the skin, mucous membranes, or genitals
- Staph aureus is one of the most common cause of bacteremia in healthcare setting
- Gram negative bacteremia accounts for a quarter to half of bloodstream infections.
- Group A strep accounts for 0.6% of bacteremia.
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:
- 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.
- 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
- Patients should undergo cardiac echo if staph aureus bacteremia is found to look for endocarditis
- 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