Gram-negative bloodstream infections in pediatric patients: antimicrobial resistance and factors associated with mortality.

BACKGROUND

Gram-negative bloodstream infections (BSIs) are associated with substantial morbidity and mortality in pediatric patients, particularly among critically ill children. Increasing antimicrobial resistance among Gram-negative pathogens has further complicated empirical treatment strategies and limited therapeutic options. This study aimed to evaluate antimicrobial resistance patterns and factors associated with mortality in pediatric patients with Gram-negative BSIs.

METHODS

This retrospective cohort study included pediatric patients aged 0-18 years with laboratory-confirmed Gram-negative BSIs diagnosed between January 2022 and September 2025 at a tertiary care center. Demographic characteristics, invasive procedures, laboratory findings, antimicrobial susceptibility profiles, treatment-related variables, and clinical outcomes were analyzed. Factors associated with all-cause in-hospital mortality were evaluated using an exploratory multivariable logistic regression model.

RESULTS

A total of 252 pediatric patients were included. Klebsiella spp. (46.4%) and Acinetobacter spp. (28.6%) were the most frequently isolated pathogens. High resistance rates were observed for gentamicin (58.3%), ciprofloxacin (57.1%), imipenem (56.0%), and meropenem (48.4%). Ceftazidime-avibactam resistance was significantly associated with study year (p = 0.008). The overall all-cause in-hospital mortality rate was 31.7%. Prior meropenem exposure and antimicrobial treatment modification after blood culture collection were associated with higher mortality. In the revised multivariable model, central venous catheter use (adjusted OR=13.58, 95% CI: 5.02-36.60), thrombocytopenia (adjusted OR=4.82, 95% CI: 2.10-11.02), total parenteral nutrition (adjusted OR=4.83, 95% CI: 2.09-11.13), mechanical ventilation (adjusted OR=3.74, 95% CI: 1.41-9.97), and meropenem resistance (adjusted OR=3.00, 95% CI: 1.28-7.03) were independently associated with mortality.

CONCLUSIONS

Gram-negative BSIs in pediatric patients were associated with substantial antimicrobial resistance and considerable all-cause in-hospital mortality. The increase in ceftazidime-avibactam resistance should be interpreted cautiously because molecular characterization was not performed. Continuous local surveillance, antimicrobial stewardship, and infection prevention strategies are important, particularly in high-risk neonatal and pediatric intensive care populations.