Anaerobic bacteremia in the elderly.

Anaerobic bacteremia occurred in 68 patients over the age of 60 in a university hospital. These elderly patients were more likely than younger patients to have an underlying malignancy. Anaerobes involved included Bacteroides fragilis group (64 isolates), Bacteroides melaninogenicus group (11) and Clostridium species (11). Polymicrobial bacteremia was common, occurring in 32.3% of patients. Mortality in patients who had surgery to remove the source of anaerobes was 43.3%, compared to 81.7% in patients with no surgical treatment. Overall mortality was 66.1%, much higher than noted in younger populations.