Enterococcal bacteremia in the surgical intensive care unit. Does vancomycin resistance affect mortality? The Johns Hopkins SICU Study Group

Abstract

Objective: To determine the incidence and mortality rate associated with nosocomial bacteremia caused by vancomycin-resistant Enterococcus in a surgical intensive care unit.

Design: A retrospective study.

Setting: The surgical intensive care unit of a large university hospital tertiary referral center.

Patients: All patients in the surgical intensive care unit with a documented nosocomial bacteremia between January 1, 1992, and December 31, 1994.

Interventions: None.

Main outcome measure: Mortality rate.

Results: Of the 134 nosocomial bacteremic episodes, 30.6% involved enterococci; 24.4% of the enterococci were resistant to vancomycin. Patients with vancomycin-resistant enterococcal bacteremia had a significantly longer hospital stay (mean +/- SD, 28 +/- 18 vs 12 +/- 10 days; P = .005) and were more likely to have been treated with vancomycin (70% vs 10.3%; P = .001) than patients with vancomycin-sensitive enterococcal bacteremia. The mortality (41.0%) associated with enterococcal bacteremia was similar to the overall bacteremic mortality (41.7%). There was no difference in episode-specific mortality associated with vancomycin-resistant enterococci (40%) vs vancomycin-sensitive enterococci (38.7%). Of the 4 deaths associated with vancomycin-resistant enterococcal bacteremia, only 2 occurred within 14 days of the bacteremia, as did 8 of 12 deaths associated with vancomycin-sensitive enterococcal bacteremia (P = .64).

Conclusions: Enterococci were the most commonly isolated nosocomial blood-borne pathogens in the surgical intensive care unit. Nearly 25% of the enterococcal bacteremic episodes were resistant to vancomycin. Vancomycin-resistant Enterococcus is associated with a prolonged hospital stay and with vancomycin use. Nevertheless, vancomycin resistance itself does not increase the mortality rate associated with enterococcal bacteremia.