Utility of peripheral blood cultures in bacteremic pediatric cancer patients with a central line.

PURPOSE: The utility of peripheral blood cultures in febrile neutropenic children with cancer and central venous catheters (CVC) is controversial. Our primary objective was to describe true bloodstream infections detected only by peripheral culture. Our secondary objectives were to describe true bloodstream infections detected only by CVC culture and to describe probable contaminants detected in both types of blood cultures.
METHODS: We included children with cancer who had peripheral and CVC cultures obtained on the same day in which at least one culture was positive. Only cultures obtained prior to the initiation of broad-spectrum antibiotics were included. We defined true bloodstream infections due to common contaminants (such as coagulase-negative Staphylococcus) as occurring if multiple cultures were positive for the same organism or if sepsis was present.
RESULTS: Between January 2002 and July 2007, 318 episodes of bloodstream infection from 224 children were included. Of these, 228/318 (71.7%) were classified as true bloodstream infections while 90/318 (28.3%) were classified as contaminants. Importantly, 28/228 (12.3%) true bloodstream infections were detected only in peripheral culture while 85/228 (37.3%) true bloodstream infections were detected only by CVC cultures. Contaminants were identified in peripheral culture in 45/318 (14.2%) of episodes and in CVC culture in 45/318 (14.2%) episodes.
CONCLUSIONS: True bloodstream infections frequently are only detected in the peripheral culture. These data support continuation of the practice of routine peripheral cultures in addition to CVC cultures at the onset of fever for children with cancer who are not already receiving broad-spectrum antibiotics.