Bacterial bloodstream infections in pediatric oncology patients in a tertiary medical center: pathogen distribution, antimicrobial nonsusceptibility, and outcomes.

UNLABELLED: The purpose of this study was to analyze bacterial bloodstream infections (BSIs) occurring in hospitalized pediatric hemato-oncology patients during 2012 to 2023. Data on 775 bacterial BSI episodes occurring in 456 patients (292, 63.04%, hematological malignancies and 164, 35.96%, solid tumors) were retrospectively collected and analyzed. In total, 362 (46.71%) bacterial-BSIs had profound neutropenia; 849 pathogens were isolated; gram-negative (GN) (68.78%, 584/849) were more common than gram-positive (GP) pathogens (30.86%, 262/849), P < 0.001. The most frequent GN isolates were Klebsiella spp. (20.38% of all isolates), Escherichia coli (19.20%), and Pseudomonas aeruginosa (12.01%); the most common GP isolates were Streptococcus viridans (9.19%) Enterococcus spp. (6.36%), and Staphylococcus aureus (6.12%, 21.15% MRSA). An increase in GN rates was observed in 2018-2023 versus 2012-2017 (74.16% vs. 63.22%, P = 0.001). Overall nonsusceptibility rates of Klebsiella spp. and E. coli were 80.13% and 90.07% for piperacillin, 16.76% and 9.82% for amikacin, 69.19% and 50.31% for ceftriaxone, 34.68% and 23.92% for piperacillin/tazobactam, and 8.72% and 1.85% for meropenem. Nonsusceptibility rates of Acinetobacter baumannii were 57.14% for both piperacillin/tazobactam and meropenem. The appropriateness of empiric antibiotic therapy (EAT) with piperacillin/tazobactam was lower than piperacillin/tazobactam + amikacin (62.61% vs. 90.45%, P < 0.0001). PICU admission was required in 230 (29.68%); 7-day and 30-day mortality rates were 6.36% and 14.69%, respectively. CONCLUSIONS: We report an increase in GN-BSIs and in nonsusceptibility rates of Klebsiella spp. and E. coli to several first/second-line antibiotics used in empiric antibiotic therapy. In our setting, an EAT protocol including piperacillin/tazobactam and amikacin covered most pathogens and should be considered in stable children with suspicion of BSI. WHAT IS KNOWN: • Bloodstream infections and antibiotic resistance rates are increasing in pediatric hemato-oncology patients. WHAT IS NEW: • We found a dominance of gram-negative pathogens and moderate to high resistance rates of Klebsiella spp. and Escherichia coli for piperacillin/tazobactam, ciprofloxacin, and ceftriaxone. • Empiric antibiotic therapy was appropriate for 77.07% of evaluable pathogens. • The appropriateness of empiric antibiotic therapy with piperacillin/tazobactam alone was lower than that of piperacillin/tazobactam plus amikacin.