Evaluation of outcome in critically ill patients with nosocomial enterobacter bacteremia: results of a matched cohort study.

Study Objective: To evaluate the clinical impact of nosocomial Enterobacter bacteremia in critically ill patients.

Design: Retrospective (January 1992 to December 2000) matched cohort study.

Setting: Fifty-four-bed ICU (including medical, surgical, cardiosurgical ICU, and burns unit) from a university hospital.

Patients: Sixty-seven ICU patients with Enterobacter bacteremia (case patients) and 134 control patients.

Intervention: Matching of control patients (1:2 ratio) was on the basis of the APACHE (acute physiology and chronic health evaluation) II system. As expected, mortality can be derived from this severity-of-disease classification system; this matching procedure results in an equal expected mortality rate for patients with Enterobacter bacteremia and control patients.

Results: The overall rate of appropriate antibiotic therapy in patients with Enterobacter bacteremia was high (96%) and initiated soon after the onset of the bacteremia (0.5 +/- 0.9 days). Patients with Enterobacter bacteremia had more hemodynamic instability (p = 0.015), longer ICU stay (p < 0.001), and ventilator dependence (p < 0.001). No differences between case and control patients were found in age (52 years vs 53 years, p = 0.831), prevalence of acute renal failure (16% vs 16%, p = 0.892), and acute respiratory failure (93% vs 84%, respectively; p = 0.079). In-hospital mortality rates for case and control patients were not different (34% vs 39%, respectively; p = 0.536).

Conclusion: After accurate adjustment for severity of underlying disease and acute illness, no difference was found between ICU patients with Enterobacter bacteremia and matched control patients. In the presence of fast and appropriate antibiotic therapy, Enterobacter bacteremia does not adversely affect the outcome in ICU patients.