Effect of antimicrobial therapy on mortality in 377 episodes of Enterobacter spp. bacteraemia.

OBJECTIVES The impact of appropriate antimicrobial therapy and antimicrobial resistance on the outcome of bacteraemia due to Enterobacter spp. remains unclear. The aim of our study was to evaluate the effect of antimicrobial therapy in 377 consecutive episodes of Enterobacter bacteraemia. PATIENTS AND METHODS This includes retrospective analysis of a prospectively collected cohort. Clinical variables recorded were age, underlying diseases, use of corticosteroids, prognosis of underlying disease according to the McCabe and Jackson criteria, source of bacteraemia, need for mechanical ventilation, empirical antibiotic treatment, definitive treatment, antimicrobial susceptibility, presentation with septic shock and 30 day mortality rate. Univariate and multivariable analyses were performed to analyse the influence of antibiotic treatment and cephalosporin resistance on mortality. RESULTS Between 1991 and 2006, 377 episodes of bacteraemia due to Enterobacter spp. (2.2%) were recorded. The frequency of Enterobacter bacteraemia significantly increased over these years. The overall mortality rate was 12.5% (47 of 377). Independent factors associated with 30 day mortality in patients with monomicrobial bacteraemia were rapidly fatal prognosis when compared with non-fatal prognosis, presentation with septic shock, patient under mechanical ventilation and unknown source of infection. The only factor independently associated with lower 30 day mortality was the empirical use of piperacillin/tazobactam. CONCLUSIONS Enterobacter spp. are an increasing cause of bacteraemia. The empirical use of piperacillin/tazobactam was independently associated with a lower 30 day mortality rate.