Is Vancomycin Resistance in Enterococci Predictive of Inferior Outcome of Enterococcal Bacteremia?

Sir—In the March 2000 issue of Clinical Infectious Diseases, Garbutt et al. [1] reported that resistance to vancomycin does not increase the mortality rate associated with Enterococcus faecium bacteremia. We retrospectively reviewed a protocol that evaluated all cases of enterococcal bacteremia (EB) at 5 university hospitals located in Bratislava, Banska Bystrica, Nitra, Trnava, and Kosice in the Slovak Republic. To analyze risk factors for vancomycin resistance (table 1), we performed both univariate and multivariate analyses of 101 cases of EB. We used STAT ADV 21, a software package of the Postgraduate Medical School, Bratislava, Slovak Republic, to compare 2 subgroups of EB: EB caused by vancomycin-resistant enterococci (9 cases [5 cases of Enterococcus faecalis EB and 4 cases of E. faecium EB]) and EB caused by vancomycin-susceptible enterococci (92 cases [85 cases of E. faecalis EB, 4 cases of E. faecium EB, and 3 cases of Enterococcus gallinarum EB). Risk factors for and outcome of vancomycin-resistant versus vancomycin-susceptible enterococcal bacteremia (EB). Our findings, which are similar to those reported by Garbutt et al. [1], showed that there was no difference between vancomycin-resistant and vancomycin-susceptible EB with regard to associated mortality. However, several risk factors for vancomycin-resistant EB were found in a multiple logistic regression model. These risk factors included E. faecium as the etiologic agent (P < .001; OR, 6.05), and resistance to ampicillin (P < .035; OR, 2.44) and chloramphenicol (P < .02; OR, 3.05). The vancomycin-resistant enterococci caused bacteremia more frequently in individuals who had neutropenia (P < .01; OR, 4.22) and in those who had received prior antibiotic therapy with cephalosporin (P < .001; OR, 10.3), vancomycin (P < .01; OR, 7.1), and/or quinolones (P < .03; OR, 5.5). Our results indicate that the clinical significance of vancomycin-resistant EB is not clear, since patients who are infected with vancomycin-resistant enterococci did not have a higher mortality rate than did those patients who had EB due to vancomycin-susceptible isolates.