Bloodstream infection: Differences between young-old, old, and old-old patients

Objectives: To compare the epidemiological and microbiological characteristics of bloodstream infection (BSI) between the young old (65-75), old (76-85), and old old (>85). Design: Retrospective study. Setting: Forty-six hospitals in southeast France. Participants: One thousand seven hundred forty patients aged 65 and older with BSI, seen between January 1 and December 31, 1998. Measurements: Epidemiological and microbiological data and outcome. Results: Community-acquired BSIs (CABSIs) were significantly more frequent in the old old, but microbiological data were similar to those in the young-old group. Conversely, microbiological data were significantly different for nosocomial BSIs (NSBIs). Escherichia coli was the main pathogen in the old old and Staphylococcus aureus in the young old. Mortality was independently associated with the presence of methicillin-resistant S. aureus in NSBI and CABSI. Conclusions: The differences in NBSI are important in serious infectious diseases and often require empirical antibiotic therapy. Age is also a risk factor but only for CABSI and suggests that the old-old patients represent a frail population in the community. Further prospective studies are needed to confirm these findings and analyze predisposing factors.