Gram-negative bloodstream infections: where can we do better? A retrospective cohort study.

Purpose: Gram-negative bloodstream infections (GN-BSI) significantly impact hospital admissions, presenting major health challenges. Despite guidelines advocating de-escalation, oralization, and appropriate treatment durations, real-world clinical management remains unclear.

Methods: This retrospective observational study assessed GN-BSI management at a tertiary care hospital, comparing uncomplicated (uGN-BSI) and complicated (cGN-BSI) cases from January to December 2022. It focused on identifying risk factors for suboptimal therapy, defined as failure to adopt the narrowest effective spectrum suggested by susceptibility reports within 24 h of result availability.

Results: Among 194 patients studied, 52.1% had uGN-BSI which were predominantly caused by Escherichia coli (54.6%) with a urinary tract source, while cGN-BSI showed higher rates of AmpC producers (22.6%) and Pseudomonas aeruginosa (8.6%). Treatment durations deviated by a median of + 2 days (interquartile 0-5) for cGN-BSI. Missed opportunities for oralization were higher in uGN-BSI (76.2%) than in cGN-BSI (55.9%). Average time to oralization was 5.5 days in uGN-BSI versus 6.5 days in cGN-BSI. Rates of optimal treatment initiation within 24 h post-antibiogram were low (uGN-BSI: 22.8%, cGN-BSI: 26.9%). Third-generation cephalosporine resistant isolates (OR 0.3, CI95% 0.1-0.9) and AmpC-producers (OR 0.3, CI95% 0.1-0.8) were least associated with suboptimal therapy, while urinary tract sources in uGN-BSI trended to pose higher risk. cGN-BSI patients had fewer missed oralization opportunities than uGN-BSI patients, with a protective trend in the multivariate (OR 0.5, CI95% 0.2-1).

Conclusion: GN-BSI management frequently does not meet guideline standards, especially in de-escalation and oralization. uGN-BSI could benefit from antibiotic stewardship interventions, whereas cGN-BSI requires tailored strategies, including individualized ID consultations.