Clinical and Microbiological Features of Acinetobacter lwoffii Bacteremia in Children: A Single-Center Retrospective Cohort Study

Objective: Acinetobacter lwoffii is an environmental organism and skin commensal with low intrinsic virulence. We describe the clinical, laboratory, and microbiological features of pediatric A. lwoffii bacteremia. Methods: We retrospectively reviewed 50 pediatric patients aged 2 months to 18 years whose blood cultures grew A. lwoffii at a tertiary pediatric center between January 2015 and December 2023. Inclusion were concurrent growth in paired culture sets and specialist confirmation that the clinical findings were compatible with infection. Community- and hospital-acquired infections were compared with Mann-Whitney U and Fisher exact tests. Exact 95% confidence intervals were calculated for susceptibility estimates. Results: The laboratory processed 88,258 pediatric blood cultures and recovered 2,023 Acinetobacter isolates; A. lwoffii accounted for 2.5%. Median age was 28 months (IQR 7.0–60.5), and 34 infections (68%) were community acquired. Hospital admission occurred in 88%, intensive care was required in 18%, and empirical treatment was successful in 94%; no deaths occurred. Community- and hospital-acquired infections did not differ significantly in any measured characteristic. Susceptibility exceeded 90% for meropenem, imipenem, and gentamicin but was 70% for trimethoprim-sulfamethoxazole (95% CI 56.2–80.9). All isolates were reported susceptible to colistin and tigecycline, although colistin was not tested by reference broth microdilution and tigecycline lacked Acinetobacter-specific breakpoints. Conclusion: A. lwoffii bacteremia generally had a mild course with favorable outcomes. We did not detect significant differences between community- and hospital-acquired infections, although the small subgroup sizes limit statistical power. Retrospective data cannot establish that every positive culture represented invasive disease. Prospective studies with standardized adjudication and molecular species confirmation are needed.