414 - Outcomes of Blood Culture Best Practice Implementation in Immunocompromised Children: A Multi-Center Study

Publication Number: 2402.414

William Warker, The Children's Hospital at Montefiore, Bronx, NY, United States; Zeinab Houmani, Children’s Hospital at Montefiore, Bronx, NY, United States; Julia Piwoz, Children's Hospital at MontefioreAlbert EInstein College of Medicine, Bronx, NY, United States; Sara Kaswan, Albert Einstein College of Medicine, New York, NY, United States; Deniz Aygun, Albert Einstein College of Medicine, Bronx, NY, United States; Marc Foca, Albert Einstein College of Medicine, Bronx, NY, United States; Philip Lee, The Children's Hospital at Montefiore, Bronx, NY, United States; Alex Nanchanatt, Memorial Sloan Kettering Cancer Center, New York, NY, United States; Jennifer Schloss, Memorial Sloan Kettering Cancer Center, New York, NY, United States; Maria Luisa Sulis, Memorial Sloan Kettering Cancer Center, New York, NY, United States; Alexander Chou, Weill Cornell Medicine, New York, NY, United States; Karen Acker, Weill Cornell Medicine, New York, NY, United States; Jodi Riggs, Stony Brook Children's Hospital, Commack, NY, United States; Priya H. Marathe, Memorial Sloan Kettering Cancer Center, New York, NY, United States; Christy Beneri, Stony Brook Children's Hospital, Stony Brook, NY, United States; Meghan G. Italo, Stony Brook University School of Medicine - - Stony Brook, NY, Huntington, NY, United States; Brenda I.. Anosike, Albert Einstein College of Medicine, Bronx, NY, United States

Background: Febrile neutropenia (FN) affects 10-45% of pediatric oncology patients, with bacteremia identified in 10-30% of cases. Blood cultures are a standard component of FN evaluation but are frequently overused, contributing to unnecessary antibiotics, false positives, prolonged hospitalization, and increased costs. Evidence indicates that cultures drawn >48 hours after fever onset provide limited diagnostic value, with positivity rates declining from 12.3-21% before antibiotics to 4.2-4.4% thereafter. The national blood culture bottle shortage (July-October 2024) prompted stewardship protocols across institutions, providing an opportunity to assess the clinical effects of reduced culture frequency.

Objective: To evaluate clinical outcomes among immunocompromised children admitted with fever or clinical change who received an initial blood culture but not daily cultures, compared with those who did.

Design/Methods: This multi-center, retrospective cohort study included 391 unique patients and 545 encounters of immunocompromised pediatric patients hospitalized with fever or clinical change at five New York institutions from March-November 2024. Data were extracted from electronic medical records and stratified by interval between cultures ( < 2 days or ≥2 days from initial culture). T-test and Wilcoxon signed-rank test were used for continuous variables; chi-squared and Fisher test were used for categorical comparisons.

Results: 163 encounters met inclusion criteria, representing cases where repeat cultures were obtained < 2 days or ≥2 days after an initial negative culture. Among these encounters, no significant associations were found between the timing of repeat cultures and outcomes such as need for NIPPV, volume repletion, inotropic support, PICU admission, or mortality (Table 1). Across all encounters, a second culture < 2 days after the initial was associated with malignancy or stem cell transplant (SCT) history (p = .01), lower WBC and ANC (p = .001 & p = .003), and positive respiratory pathogen panel (RPP) (p = .04). Similarly, a first-to-second repeat culture interval < 2 days correlated with malignancy or SCT history (p = .009), lower WBC and ANC (p = .03 & p = .009), positive RPP (p = .008), and positive initial culture (p = .05) (Table 2).

Conclusion(s): Reducing the frequency of repeat blood cultures to ≥2 days after the initial culture decreased culture utilization in immunocompromised children without adversely affecting clinical outcomes. These findings support adherence to blood culture stewardship best practices in managing stable pediatric patients with FN.

Table 1. Patients With Negative Initial Blood Cultures
SCT: Stem Cell Transplant; IQR: Interquartile Range; NIPPV: Non-Invasive Positive Pressure Ventilation; ANC: Absolute Neutrophil Count; * p < 0.05; *** p < 0.01

Table 2. All Encounters With Repeat Blood Cultures
SCT: Stem Cell Transplant; IQR: Interquartile Range; ANC: Absolute Neutrophil Count; * p < 0.05; *** p < 0.01