Impact of a multimodal strategy combining a new standard of care and restriction of carbapenems, fluoroquinolones and cephalosporins on antibiotic consumption and resistance of Pseudomonas aeruginosa in a French intensive care unit.

This study aimed to assess whether post-prescription review and feedback (PPRF) of all antibiotics, with restriction of carbapenems, fluoroquinolones and third-generation cephalosporins (3GCs), along with a change in medical standard of care impacted antibiotic consumption and bacterial antimicrobial resistance in a French medical/surgical intensive care unit (ICU). A 4-year before (2007-2010) and after (2011-2014) retrospective comparative study was performed. Antibiotic consumption was evaluated in defined daily doses per 1000 patient-days. The rates of Pseudomonas aeruginosa resistance to piperacillin, ceftazidime, ciprofloxacin, imipenem and amikacin and of AmpC-hyperproducing group 3 Enterobacteriaceae were assessed. Consumption of fluoroquinolones decreased by -85%, carbapenems by -58%, 3GCs by -50% and glycopeptides by -66% (P ≤ 0.0001). Consumption of penicillins with and without β-lactamase inhibitors increased by +72% and +78%, sulfonamides by +172% and macrolides by +267% (P < 0.0001). Pseudomonas aeruginosa resistance rates for all antibiotics tested and the proportion of AmpC-hyperproducing group 3 Enterobacteriaceae decreased (P ≤ 0.01). The median length of stay, use of vasopressors and invasive mechanical ventilation decreased, and the use of renal replacement therapy increased (P < 0.05). The initial severity score (SAPS II) increased (P < 0.01) due to changes in practice, with no impact on in-hospital mortality (P = 0.07). In conclusion, changes in medical care along with PPRF and a restriction of high ecological impact antibiotics were associated with a shift towards the consumption of low ecological impact antibiotics in an ICU. Rates of resistant P. aeruginosa and of AmpC-hyperproducing group 3 Enterobacteriaceae decreased simultaneously.