Utility of Obtaining Follow-Up Blood Cultures in Gram-Negative Bacterial Bloodstream Infection Among Patients With Hematologic Malignancies

Background: There is an ongoing debate on the benefit of obtaining repeat blood cultures for Gram-negative bacterial bloodstream infections (GNBSI). However, there is a scarcity of data concerning patients with hematologic malignancies. We sought to assess the utility of obtaining follow-up blood cultures (FUBC) in GNBSI among patients with hematologic malignancies.

Methods: A retrospective chart review was conducted to identify all admitted patients with hematologic malignancies with GNBSI from 2018 to 2021 at a tertiary academic medical center. We collected demographics, cancer history and treatment, microbiology and antibiotic use, and clinical course. Descriptive statistics were used.

Results: A total of 46 episodes of GNBSI among 38 patients were included. The median age was 61.5 years, 63% were male, 50% were White, and 16% were Latinx. Most patients had acute myeloid leukemia (60%), and the most common chemotherapy regimen was cytarabine or nelarabine regimens (35%). Klebsiella pneumoniae was responsible for 37% of the GNBSI cases, in the setting of long-term central venous catheter use (65%) and gastrointestinal sources (50%). FUBCs were collected among almost all patients (98%). Only three cases (7%) had positive FUBC: one had a delay in appropriate therapy, another had a lack of source control, and the last case did not have a source identified. Most patients were treated with beta-lactams (52%) with duration 8-14 days (52%). 22% were admitted to ICU and 9% died during their hospitalization.

Conclusion: We found a few cases of positive FUBC. Routine FUBC may not be appropriate for all GNBSI patients with hematological malignancies, particularly during the current blood culture bottle shortage.