Systemic inflammatory response syndrome in adult patients with nosocomial bloodstream infections due to enterococci

Background: Enterococci are the third leading cause of nosocomial bloodstream infection ( BSI). Vancomycin resistant enterococci are common and provide treatment challenges; however questions remain about VRE's pathogenicity and its direct clinical impact. This study analyzed the inflammatory response of Enterococcal BSI, contrasting infections from vancomycin-resistant and vancomycin-susceptible isolates. Methods: We performed a historical cohort study on 50 adults with enterococcal BSI to evaluate the associated systemic inflammatory response syndrome ( SIRS) and mortality. We examined SIRS scores 2 days prior through 14 days after the first positive blood culture. Vancomycin resistant (n = 17) and susceptible infections ( n = 33) were compared. Variables significant in univariate analysis were entered into a logistic regression model to determine the affect on mortality. Results: 60% of BSI were caused by E. faecalis and 34% by E. faecium. 34% of the isolates were vancomycin resistant. Mean APACHE II (A2) score on the day of BSI was 16. Appropriate antimicrobials were begun within 24 hours in 52%. Septic shock occurred in 62% and severe sepsis in an additional 18%. Incidence of organ failure was as follows: respiratory 42%, renal 48%, hematologic 44%, hepatic 26%. Crude mortality was 48%. Progression to septic shock was associated with death ( OR 14.9, p <.001). There was no difference in A2 scores on days - 2, - 1 and 0 between the VRE and VSE groups. Maximal SIR ( severe sepsis, septic shock or death) was seen on day 2 for VSE BSI vs. day 8 for VRE. No significant difference was noted in the incidence of organ failure, 7-day or overall mortality between the two groups. Univariate analysis revealed that AP2> 18 at BSI onset, and respiratory, cardiovascular, renal, hematologic and hepatic failure were associated with death, but time to appropriate therapy > 24 hours, age, and infection due to VRE were not. Multivariate analysis revealed that hematologic ( OR 8.4, p =.025) and cardiovascular failure ( OR 7.5, p = 032) independently predicted death. Conclusion: In patients with enterococcal BSI, ( 1) the incidence of septic shock and organ failure is high, ( 2) patients with VRE BSI are not more acutely ill prior to infection than those with VSE BSI, and ( 3) the development of hematologic or cardiovascular failure independently predicts death.