Blood culture contamination

• Almost never true bacteremia
  • Corynebacterium, except Corynebacterium jeikeium
  • Bacillus, except Bacillus anthracis
  • Cutibacterium acnes
• Sometimes true bacteremia
  • Micrococcus
  • Enterococcus
  • Clostridium perfringens
  • Coagulase-negative staphylococci
• Always true bacteremia
  • Staphylococcus aureus
  • Streptococcus pneumoniae
  • Escherichia coli and other Enterobacterales
  • Pseudomonas aeruginosa
  • Candida albicans
• Coagulase-negative staphylococci are rarely significant (12%), but because they are so common (70-80% of all positive cultures), they are the most common cause of bacteremia