Antibiotic strategies in severe nosocomial sepsis: why do we not de-escalate more often?

OBJECTIVES To assess the use of antibiotic de-escalation in patients with hospital-acquired severe sepsis in an academic setting. DESIGN We reviewed all episodes of severe sepsis treated over a 1-yr period in the department of intensive care. Antimicrobial therapy was considered as appropriate when the antimicrobial had in vitro activity against the causative microorganisms. According to the therapeutic strategy in the 5 days after the start of antimicrobial therapy, we classified patients into four groups: de-escalation (interruption of an antimicrobial agent or change of antibiotic to one with a narrower spectrum); no change in antibiotherapy; escalation (addition of a new antimicrobial agent or change in antibiotic to one with a broader spectrum); and mixed changes. SETTING A 35-bed medico-surgical intensive care department in which antibiotic strategies are reviewed by infectious disease specialists three times per week. PATIENTS One hundred sixty-nine patients with 216 episodes of severe sepsis attributable to a hospital-acquired infection who required broad-spectrum β-lactam antibiotics alone or in association with other anti-infectious agents. MEASUREMENTS AND MAIN RESULTS The major sources of infection were the lungs (44%) and abdomen (38%). Microbiological data were available in 167 of the 216 episodes (77%). Initial antimicrobial therapy was inappropriate in 27 episodes (16% of culture-positive episodes). De-escalation was applied in 93 episodes (43%), escalation was applied in 22 episodes (10%), mixed changes were applied in 24 (11%) episodes, and there was no change in empirical antibiotic therapy in 77 (36%) episodes. In these 77 episodes, the reasons given for maintaining the initial antimicrobial therapy included the sensitivity pattern of the causative organisms and previous antibiotic therapy. The number of episodes when the chance to de-escalate may have been missed was small (4 episodes [5%]). CONCLUSION Even in a highly focused environment with close collaboration among intensivists and infectious disease specialists, de-escalation may actually be possible in <50% of cases.