From the Guidelines
Yes, finding Staphylococcus hemolyticus in 1 out of 2 bottles in a blood culture set should be considered contamination in most clinical scenarios. When only one bottle grows this organism, especially when it's a common skin commensal like S. hemolyticus, this pattern typically represents contamination during the collection process rather than true bacteremia, as indicated by the American Society for Microbiology evidence-based laboratory medicine practice guidelines 1. True bloodstream infections usually result in both bottles becoming positive. However, clinical context remains important - if the patient has symptoms consistent with infection, has indwelling medical devices, or is immunocompromised, even a single positive bottle might warrant closer evaluation. Some key points to consider in this scenario include:
- The type of organism isolated, in this case, Staphylococcus hemolyticus, which is often considered a contaminant when found in a single blood culture bottle 1
- The clinical context of the patient, including the presence of symptoms or underlying conditions that could increase the risk of true infection
- The importance of proper skin preparation and collection technique to minimize the risk of contamination in future blood cultures, as emphasized by the guidelines 1. To reduce contamination rates in future collections, ensure proper skin preparation with chlorhexidine, allow adequate drying time for the antiseptic, and use proper technique when collecting blood cultures.
From the Research
Staphylococcus Aureus Contamination
- Staphylococcus aureus is a common cause of infections in hospitals and the community, and can cause a wide range of human infections, from minor skin infections to severe tissue infection and sepsis 2, 3.
- The bacteria can be opportunistic, taking advantage of compromised immune systems or breaches in sterile technique to cause infection 2.
- Prevention of the spread of S. aureus infection relies on the use of contact precautions and adequate procedures for infection control, such as proper disinfection and sterilization of medical devices 4, 5.
Sterile Technique and Infection Control
- Sterile technique is an essential patient safety principle that reduces the risk of microbial transmission to patients during surgery 6.
- The ability to establish and maintain a sterile environment is an important skill for all perioperative team members, and understanding the principles of sterile technique is crucial for anyone entering the perioperative environment 6.
- Failure to ensure proper cleaning and sterilization or disinfection of medical devices may lead to patient-to-patient transmission of pathogens, including S. aureus 4, 5.
Contamination of Bottles
- There is no direct evidence in the provided studies to suggest that 1 out of 2 bottles being staph hemolytic is considered contaminated.
- However, the studies emphasize the importance of proper disinfection and sterilization procedures to prevent the spread of infection, and the potential for S. aureus to cause infection if proper protocols are not followed 4, 5, 2, 3.