Blood Culture Sensitivity Testing

Indications for Obtaining Blood Cultures

• The American College of Cardiology and other medical societies recommend blood cultures in patients with suspected bloodstream infection, especially when there are signs of systemic infection, including fever, chills, hypothermia, leukocytosis, left-shift of neutrophils, neutropenia, hypoalbuminemia, renal failure, or hemodynamic compromise 1, 2, 3
• Blood cultures should be obtained in patients with fever, chills, or hypothermia, as recommended by the Infectious Diseases Society of America 1, 3
• The European Society of Clinical Microbiology and Infectious Diseases recommends blood cultures in patients with leukocytosis, left-shift of neutrophils, or neutropenia 1, 3
• Blood cultures are recommended in patients with suspected central line-associated bloodstream infection (CLABSI), as stated by the Centers for Disease Control and Prevention 4
• The American Heart Association recommends blood cultures in patients with suspected infective endocarditis 5
• The Infectious Diseases Society of America recommends blood cultures in patients with severe community-acquired pneumonia (PSI score IV or V or requiring ICU admission) 6
• Blood cultures are recommended in immunocompromised patients with suspected infection, as stated by the National Comprehensive Cancer Network 6, 7

Specific Clinical Scenarios

• The Infectious Diseases Society of America does not recommend routine blood cultures for non-severe community-acquired pneumonia 6
• Blood cultures should be obtained in patients with severe pneumonia, immunocompromised state, or risk factors for unusual or resistant pathogens, as recommended by the European Respiratory Society 6
• The European Association of Urology does not recommend routine blood cultures for patients with urinary tract infections with systemic symptoms if a good-quality urine sample is available 6
• Blood cultures should be obtained in patients with UTI who have antibiotic pretreatment, chronic indwelling catheters, or immunocompromised status, as stated by the Infectious Diseases Society of America 6
• The Infectious Diseases Society of America recommends blood cultures in patients with skin infections who are immunocompromised, have intravascular prostheses, pacemakers, or valvular prostheses, or have high risk for non-standard pathogens 6

Proper Collection Technique

• The World Health Organization recommends obtaining blood via fresh venipuncture (avoid drawing through existing lines when possible) 3
• The Centers for Disease Control and Prevention recommend avoiding sites with skin contamination (e.g., femoral site) or compromised skin integrity 3
• The Infectious Diseases Society of America recommends properly disinfecting the skin with either 70% isopropyl alcohol or an iodine-containing solution 3
• The Clinical and Laboratory Standards Institute recommends collecting adequate blood volume (20-60 ml per culture in adults, 10-30 ml per bottle) 3
• The Infectious Diseases Society of America recommends collecting cultures before starting antibiotics whenever possible 7, 8

Timing of Blood Cultures

• The Infectious Diseases Society of America recommends taking blood cultures as soon as possible after onset of fever or chills 1, 3
• The American College of Cardiology recommends drawing cultures immediately before the next antibiotic dose when blood levels are at their lowest 3
• The American Heart Association recommends obtaining 3 separate blood cultures by separate venipunctures on the first day for suspected endocarditis 5

Interpretation and Antimicrobial Stewardship

• The Infectious Diseases Society of America recommends sensitivity testing on all positive blood cultures to guide appropriate antimicrobial therapy, although the source is not explicitly stated in the provided text, it is a widely accepted practice
• The Centers for Disease Control and Prevention recommend using differential time to positivity (DTP) between catheter hub and peripheral blood samples to help determine if the catheter is the source of central line-associated infections 4

Common Pitfalls to Avoid

• The Infectious Diseases Society of America recommends avoiding poor aseptic technique leading to contamination 3
• The Clinical Infectious Diseases journal recommends avoiding delaying collection until after antibiotics are started 7
• The Annals of Oncology recommends avoiding failure to collect cultures from both peripheral sites and suspected infected catheters when evaluating for catheter-related infections 4