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

M. R. Mainous, P. A. Lipsett and M. O'Brien
Department of Surgery, Louisiana State University Medical Center, Shreveport, USA.

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.