Nosocomial bacteremia in a large Spanish teaching hospital: analysis of factors influencing prognosis.

Five hundred forty-three episodes of nosocomial bacteremia were prospectively followed in a large Spanish university hospital. The commonest isolates were Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida species. The most frequent sources of infection were intravenous lines, urinary tract, and lower respiratory tract. Overall mortality was 18%. A step-forward logistic regression analysis defined eight variables independently influencing the outcome: shock, underlying rapidly fatal disease, high-risk source of bacteremia (intraabdominal, lower respiratory tract, or not identified), age more than 70 years, hospitalization in intensive care or medical units, inappropriate antibiotic treatment, infection due to a high-risk microorganism (P. aeruginosa, Serratia marcescens, Klebsiella, Bacteroides, or Candida), and development of septic metastasis. The identification of those factors independently influencing the outcome and their possible modification may represent a further step in the control of nosocomial bacteremia by improving its prognosis.