Clarifying Appropriate Use of Central Line Blood Cultures—Reply

In Reply We thank Mermel for his thoughtful and careful review of our Teachable Moment article, “The Harm of Inappropriate Central Line Blood Cultures in Clinical Practice.” We agree that whether a positive central line culture reflects a bloodstream infection, colonization, or a false-positive result requires accounting for the outcome of each blood culture obtained. In our case, we reported that the initial central line blood culture grew coagulase-negative Staphylococcus, yet the initial and repeated peripheral cultures had negative results. As only 1 of the 2 initial blood cultures revealed infection, the positive result was limited to the central line culture, and subsequent cultures revealed negative results. This suggests colonization of the catheter hub or lumen or a false-positive result due to a skin contaminant. Coupled with an alternative explanation for the patient’s fever (ie, community-acquired pneumonia), the infectious diseases consultant did not disregard the possibility of a catheter-related bloodstream infection; rather, as stated in our initial report, they determined the risk to be low. Last, we agree that alcohol end caps are an important strategy to reduce false-positive results drawn from central lines, along with careful skin and catheter disinfection. Unfortunately, such strategies do not eliminate the risk of a false-positive result, supporting our conclusion to limit central line blood culture specimens in clinical practice to specific indications: inability to obtain peripheral blood cultures, suspected catheter-related bloodstream infection in the absence of another recognized source of infection, and neutropenic fever.

from JAMA Internal Medicine Online First https://ift.tt/80hk64b