Predictors of Mortality in Staphylococcus aureus Bacteremia
Clin. Microbiol. Rev. April 2012 25(2): 362-386
Sebastian J. van Hal, Slade O. Jensen, Vikram L. Vaska, Björn A. Espedido, David L. Paterson, and Iain B. Gosbell
aDepartment of Microbiology and Infectious Diseases, Sydney South West Pathology Service—Liverpool, South Western Sydney Local Health Network, Sydney, New South Wales, Australia
bAntibiotic Resistance and Mobile Elements Group, Microbiology and Infectious Diseases Unit, School of Medicine, University of Western Sydney, Sydney, New South Wales, Australia
cIngham Institute of Applied Medical Research, Sydney, New South Wales, Australia
dThe University of Queensland, UQ Centre for Clinical Research (UQCCR), Herston, Queensland, Australia
Staphylococcus aureus bacteremia (SAB) is an important infection with an incidence rate ranging from 20 to 50 cases/100,000 population per year. Between 10% and 30% of these patients will die from SAB. Comparatively, this accounts for a greater number of deaths than for AIDS, tuberculosis, and viral hepatitis combined. Multiple factors influence outcomes for SAB patients. The most consistent predictor of mortality is age, with older patients being twice as likely to die. Except for the presence of comorbidities, the impacts of other host factors, including gender, ethnicity, socioeconomic status, and immune status, are unclear. Pathogen-host interactions, especially the presence of shock and the source of SAB, are strong predictors of outcomes. Although antibiotic resistance may be associated with increased mortality, questions remain as to whether this reflects pathogen-specific factors or poorer responses to antibiotic therapy, namely, vancomycin. Optimal management relies on starting appropriate antibiotics in a timely fashion, resulting in improved outcomes for certain patient subgroups. The roles of surgery and infectious disease consultations require further study. Although the rate of mortality from SAB is declining, it remains high. Future international collaborative studies are required to tease out the relative contributions of various factors to mortality, which would enable the optimization of SAB management and patient outcomes.