De-escalation after empirical meropenem treatment in the intensive care unit: fiction or reality?

INTRODUCTION: De-escalation of antimicrobial therapy is often advocated to reduce the use of broad-spectrum antibiotics in critically ill patients. However, little data are available on the application of this strategy in daily clinical practice.
METHODS: This is a retrospective analysis of all meropenem prescriptions in a surgical intensive care unit (ICU) during 1 year. Age, Acute Physiology and Chronic Health Evaluation II score on admission to the ICU, site of infection, causative organism, duration of meropenem administration, other antibiotic prescription for the same infectious episode for which meropenem was administered, and ICU mortality were recorded. De-escalation was defined as the administration of an antibiotic with a narrower spectrum within 3 days of the start of meropenem.
RESULTS: Data from 113 meropenem prescriptions were available for analysis. Pulmonary (46%) and complicated intraabdominal (31%) infections were the most frequent infections. In 37 patients, meropenem was used after identification of a multiresistant gram-negative organism (MRGN), whereas in 76 patients, empirical treatment with meropenem was started. Empirical prescription of meropenem was de-escalated in 42% of the patients. In the majority of the patients in whom de-escalation was not done, no conclusive cultures were available to guide treatment; also, colonization with MRGN at other sites was frequently associated with non-de-escalation. Patients in whom antibiotics were de-escalated had a trend toward a lower mortality rate (7% vs 21%, P = .12).
CONCLUSIONS: De-escalation after empirical treatment with meropenem was performed in less than half of the patients. Reasons for not de-escalating included the absence of conclusive microbiology and colonization with MRGN.