Impact of antimicrobial strategies on clinical outcomes of adults with septic shock and community-onset Enterobacteriaceae bacteremia: de-escalation is beneficial

• We modeled the different effects of antimicrobial strategies on the clinical outcomes of adults who were critically ill with community-onset Enterobacteriaceae bacteremia.
• The antimicrobial strategies were defined by the switch between the varied antimicrobial categories ranked according to their activity spectrum against Enterobacteriaceae.
• The advantage of a de-escalated strategy on the short-term outcomes of bacteremic adults with critical illness was emphasized.
• The incorporation of a de-escalation strategy into antimicrobial stewardship programs to decrease the use of broad-spectrum antimicrobial agents was recommended.

To investigate the clinical outcomes of patients with septic shock related to community-onset monomicrobial Enterobacteriaceae (CoME) bacteremia as categorized by the strategy of antimicrobial therapy, a retrospective and observational study was conducted. Clinical information on the patients was obtained from medical records. Antibiotic regimens were ranked according to their activity spectrum against Enterobacteriaceae (category IV, highest; I, lowest). De-escalation was defined as a switch to a category with a narrower spectrum of coverage within 5 days after the bacteremic onset. Of the 189 eligible patients, 86 (45.5%) patients received de-escalation antibiotic therapy, and most (48, 55.8%) of the patients were empirically treated first with a category IV antibiotic. In a multivariate analysis for 28-day mortality, of several independent predictors, the de-escalation strategy was protective (odds ratio, 0.37; P = 0.04). In conclusion, for patients with CoME bacteremia and available susceptibility data, de-escalation of antimicrobial therapy was beneficial for improving clinical outcome.