Coagulase-Negative Staphylococci Blood Culture Interpretation

Introduction to CoNS Infection

Coagulase-negative staphylococci (CoNS) are most commonly contaminants rather than true pathogens when isolated from blood cultures, with approximately 65-94% of CoNS-positive blood cultures representing contamination rather than true bloodstream infection 1, 2

Multiple positive blood cultures from multiple sites is the best indication of true CoNS bacteremia, as recommended by the Infectious Diseases Society of America 1, 2

Single positive blood culture with negative concurrent cultures likely represents contamination, according to the Centers for Disease Control and Prevention 3, 4

Avoid unnecessary antibiotic therapy, particularly vancomycin, when CoNS is likely a contaminant, as suggested by the Centers for Disease Control and Prevention 3, 4
Obtain additional blood cultures to confirm absence of bacteremia when CoNS is likely a contaminant, as recommended by the Infectious Diseases Society of America 2
Treat uncomplicated catheter-related bloodstream infection (CRBSI) with antibiotics for 5-7 days if catheter is removed, as recommended by the Infectious Diseases Society of America 1, 2
Consider catheter removal, especially with short-term catheters, as suggested by the Infectious Diseases Society of America 2

Despite being a CoNS, Staphylococcus lugdunensis should be managed similarly to S. aureus due to its higher virulence and ability to cause endocarditis and metastatic infections, as recommended by the Infectious Diseases Society of America 1, 2

Don't automatically treat a single positive CoNS blood culture with vancomycin, as cautioned by the Centers for Disease Control and Prevention 3, 4
Don't assume all CoNS species have equal clinical significance, as noted by the Infectious Diseases Society of America 1, 2
Don't overlook the importance of proper blood culture collection technique in reducing contamination rates, as emphasized by the Centers for Disease Control and Prevention 3, 4