To the Editor Having spent the last 30 years focused on the diagnosis and management of catheter-related infections, I read with interest the Teachable Moment article by Fuher et al published recently in JAMA Internal Medicine. The authors did not state if the initial 2 sets of blood cultures revealed growth. The consultant’s disregard for the possibility of a catheter infection without localizing signs is not supported by the medical literature as most central venous catheter-related bloodstream infections (CRBSIs) do not have localizing signs. References in the article by Fuher et al are outdated, as they were written before alcohol end caps (so-called “port protectors”) came into widespread use, reducing false-positive results of catheter-drawn blood cultures. I wholly agree that catheter-drawn cultures should not be obtained if an alternative source of fever is known or suspected. However, for patients with a central venous catheter (CVC) in whom the source is unknown, then CVC-drawn and percutaneously drawn blood cultures should be obtained. The natural history of CRBSI involves the initial growth of microbes at the insertion site or hub. Over time, these microbes may migrate extraluminally or intraluminally, respectively, into the bloodstream. As such, growth of catheter-drawn blood cultures may be a harbinger of eventual CRBSI. This has recently been demonstrated to occur in patients whose CVC-drawn blood culture had growth, while percutaneously drawn cultures were unrevealing. In these patients, 21% of repeated blood cultures within 2 days revealed growth of the same microbe in percutaneously drawn blood cultures. In sum, blood cultures should be obtained percutaneously when a source other than a CVC is known or suspected. However, if the patient has a CVC and the source is unknown, then CRBSI should be in the differential diagnosis, and blood cultures should be collected from both the catheter and percutaneously. If no other source of fever is identified and the patient has growth only in CVC-drawn cultures, this may reflect colonization of the catheter hub and/or lumen, and continued intraluminal growth may seed the bloodstream, leading to growth in percutaneously drawn cultures. Lastly, be certain to collect the appropriate volume of blood and to label the blood culture bottles correctly.

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