Bacterial profile and antibiotic susceptibility of bloodstream infections among infants, children, and adolescents undergoing treatment for acute leukemia

Introduction Pediatric patients with acute leukemia are at risk of bacteremia due to disease and treatment-related toxicities. Limited data exists on pathogen distribution across different pediatric age groups. This study aims to investigate the distribution of bacterial pathogens and their susceptibility patterns across infants, children, and adolescents undergoing treatment for acute leukemia. Methods Retrospective cohort study that included pediatric patients with Acute Lymphoblastic Leukemia (ALL) or Acute Myeloid Leukemia (AML) who had positive blood cultures between 01/01/2015–31/12/2024. Bacteremia was defined as the presence of bacterial microorganisms in the bloodstream, confirmed by one or more positive blood cultures with associated symptoms. Patients were categorized into three age groups: infants (≤1 year), children (>1 to <12 years), and adolescents (≥12 to ≤18 years). Collected data included demographics, leukemia disease risk (high, standard or low), treatment phase (induction, consolidation, maintenance, relapse, or palliative care), signs and symptoms and the causative pathogen along with its susceptibility and resistance testing. Descriptive statistics were used to summarize findings. Results A total of 308 bacteremia episodes among 160 patients were identified. Of these, 291 (94%) episodes occurred in ALL patients and 17 (6%) in AML patients. The median age was 5 years (IQR 3–11 years) with children, adolescents, and infants representing 78%, 21%, and 1%, respectively. A total of 330 bacterial isolates were identified. Isolates were most frequently recovered during consolidation (30%), induction (24%), and maintenance (23%) phases. Gram-positive organisms, particularly Staphylococcus spp . predominated across all treatment phases and age groups. Whereas a higher proportion of Gram-negative organisms – including Escherichia coli , Klebsiella spp., and Pseudomon as spp. – were observed among adolescents and patients in high-risk groups. Antimicrobial resistance was confined to Escherichia coli and Klebsiella spp . exhibiting Extended-Spectrum β-lactamase and Carbapenem-Resistant Enterobacterales phenotypes across the cohort. Conclusions In this single-center descriptive study, bacteremia episodes and bacterial isolates showed descriptive differences across age groups, treatment phases, and leukemia risk categories. These findings support continued local infection surveillance. Larger multicenter studies with sufficient subgroup representation are needed to determine whether age- or phase-specific empiric therapy strategies are warranted.