Epidemiology of and antibacterial resistance in Gram-negative bloodstream infections among children with cancer and hematopoietic cell transplant recipients

Background Bacteremia occurs in up to 30% of febrile neutropenic children receiving cancer therapy or hematopoietic cell transplant (HCT) and 14% of patients with non-neutropenic fever. Increasing antimicrobial resistance among Gram-negative pathogens is a challenge to providers, who seek to limit broad-spectrum antibacterial use while providing timely and effective empiric therapy. Experts recommend that the epidemiology of GN bloodstream infections (GNBSI) should be considered in developing guidelines for management of these infections, but there are few contemporary descriptions of GNBSI in this patient population. Methods This retrospective single-center cohort study included patients <22 years of age with cancer or HCT who had received immunosuppressive therapy within 3 months, and had a laboratory confirmed GNBSI diagnosed between 11/1/21 and 2/28/25. Demographic and clinical data were abstracted from patients’ electronic medical records. Results 239 episodes of GNB were identified in 153 patients. Fourteen infections (6%) were polymicrobial. The median age was 9.3 years (range, 0.3–21.9 years). Most patients were male (58%), white (73%) and had hematologic malignancies (59%) (Table 1). Of 82 HCT recipients, 62% experienced their infection within 100 days of transplant. A total of 164 (69%) of patients had >1 medical co-morbidity. Most patients were neutropenic at the onset of infection, with 78% having an absolute neutrophil count of <500 cells/L. Almost half had another concurrent infection. The most common isolated species were Escherichia coli (31%), Klebsiella pneumoniae (19%), and Enterobacter cloacae complex (13%) (Table 2). Among 218 isolates tested, 41% were cefepime nonsusceptible. Extended spectrum beta-lactamase expression was detected in 62% of 122 Enterbacterales tested;17 isolates (7%) were carbapenem-resistant. Overall, 104/212 (49%) of isolates were multidrug resistant (MDR). Patients required intensive care unit level care in 19% of episodes. A total of 40 (17%) had a focal complication of their infection, 33 patients (18%) had a second infection caused by the same bacterial species in the study period. The mean duration of hospitalization was 8 days (range1 to 178). Mortality at hospital discharge and 30-day all-cause mortality were 7% (17 patients). Only 5 patients, however, had active GNBSI at the time of their death. Conclusion In this study, GNBSI were associated with high morbidity and significant mortality. Resistance to cefepime and MDR was common and the majority of Enterobacterales expressed ESBL. Further studies are needed to assess the impact of antibacterial resistance on the outcomes of GNBSI and to inform treatment plans that enhance patient outcomes.