2178. Sensitivity of Blood Cultures in Detection of Bacteremia in Febrile Neutropenia

BACKGROUND: Febrile neutropenia (FN) secondary to bacteremia is a treatable complication of chemotherapy that increases mortality if not promptly recognized and managed. METHODS: The sensitivity of blood cultures collected in pediatric oncology patients with FN was assessed and stratified based on the day of FN episode, culture media type, and the source of blood culture draw at a single US center between 2013 and 2018. Paired aerobic and lytic media bottles were inoculated with each culture draw using a weight-based volume of blood; anaerobic cultures were included with initial cultures starting in September of 2015. RESULTS: In a retrospective analysis of 10,596 patients, a total of 3,039 episodes of FN were identified. Of the FN episodes, 17.7% had at least one positive blood culture; 84.5%, 1.3%, 0.9% and 13.3% of positive cultures were collected on day 0, day 1, day 2 and ≥ day 3 of a febrile episode. Among the positive day 0 cultures, the median time to detection of an organism was 14.1 hours. Host characteristics of blood culture-positive FN episodes are summarized in Table 1. Bacteremia was identified in 537 FN cases; 18.1%, 11.9% and 2.6% of cultures were positive in only aerobic, lytic or anaerobic media cultures, respectively. The most commonly isolated organisms were Escherichia coli, coagulase-negative Staphylococcus, viridans group streptococcus, Klebsiella pneumoniae and Pseudomonas aeruginosa. Fifteen percent of infectious episodes with a positive blood culture were polymicrobial. CONCLUSION: In summary, the study findings have important clinical implications such as emphasizing the value of day 0 cultures and highlighting the importance of routinely collecting blood cultures in more than one media type. Despite an optimized blood culture approach, less than a fifth of FN episodes had a blood culture-based diagnosis. [Image: see text] DISCLOSURES: Randall Hayden, MD, Abbott Molecular: Advisory Board; Quidel: Advisory Board; Roche Diagnostics: Advisory Board.