A comparative analysis of pediatric Klebsiella oxytoca and Klebsiella pneumoniae bacteremia: clinical characteristics, antimicrobial susceptibility, and outcomes

Objectives While Klebsiella pneumoniae remains a common cause of paediatric bacteraemia, Klebsiella oxytoca, a member of the human commensal microbiota, is increasingly recognised as a clinically significant opportunistic pathogen. However, comparative data on these two species in paediatric bacteraemia remain scarce. This study compares the clinical characteristics, antimicrobial susceptibility patterns, and outcomes of K. pneumoniae and K. oxytoca bacteraemia in hospitalised children.Methods We retrospectively reviewed the medical records of paediatric patients aged 1 month to 18 years with blood cultures positive for K. pneumoniae or K. oxytoca between January 2018 and December 2024.Results A total of 132 children were included: 42 with K. oxytoca bacteraemia and 90 with K. pneumoniae bacteraemia. Children with K. oxytoca bacteraemia were significantly older than those with K. pneumoniae bacteraemia (median age, 90 vs. 25 months; p = 0.003). Gastrointestinal comorbidities and prior abdominal surgery were more common in the K. oxytoca group. While K. pneumoniae bacteraemia predominantly occurred as hospital-onset infection, K. oxytoca bacteraemia was more frequently community-onset (p < 0.001). Isolates of K. oxytoca demonstrated higher overall susceptibility to commonly used antibiotics. Rates of sepsis or septic shock, paediatric intensive care unit admission, and 30-day mortality did not differ between the groups.Conclusions Compared with K. pneumoniae, K. oxytoca bacteraemia was more frequently community-onset, associated with gastrointestinal comorbidities or prior abdominal surgery, and caused by more susceptible isolates. These findings underscore the importance of accurate species identification and have direct implications for empirical antibiotic selection, supporting antimicrobial stewardship strategies in paediatric bacteraemia.