THE CLINICAL-SIGNIFICANCE OF POSITIVE BLOOD CULTURES IN THE 1990S - APROSPECTIVE COMPREHENSIVE EVALUATION OF THE MICROBIOLOGY, EPIDEMIOLOGY, AND OUTCOME OF BACTEREMIA AND FUNGEMIA IN ADULTS

To assess changes since the mid-1970s, we reviewed 843 episodes of pos itive blood cultures in 707 patients with septicemia. The five most co mmon pathogens were Staphylococcus aureus, Escherichia coli, coagulase -negative staphylococci (CNS), Klebsiella pneumoniae, and Enterococcus species, Although CNS were isolated most often, only 12.4% were clini cally significant. Half of all episodes were nosocomial, and a quarter had no recognized source. Leading identifiable sources included intra venous catheters, the respiratory and genitourinary tracts, and intraa bdominal foci. Septicemia-associated mortality was 17.5%. Patients who received appropriate antimicrobial therapy throughout the course of i nfection had the lowest mortality (13.3%). Multivariate analysis showe d that age (relative risk [RR], 1.80), microorganism (RR, 2.27), sourc e of infection (RR, 2.86), predisposing factors (RR, 1.98), blood pres sure (RR, 2.29), body temperature (RR, 2.04), and therapy (RR, 2.72) i ndependently influenced outcome. Bloodstream infections in the 1990s a re notable for the increased importance of CNS as both contaminants an d pathogens, the proportionate increase in fungi and decrease in anaer obes as pathogens, the emergence of Mycobacterium avium complex as an important cause of bacteremia in patients with advanced human immunode ficiency virus infection, and the reduction in mortality associated wi th infection.