Bloodstream infections in patients with or without cancer in a large community hospital

Cancer is associated with an increased risk of acquiring bloodstream infection (BSIs). Most knowledge on pathogens and outcome are derived from specialised cancer centres. We here sought to compare causative micro-organisms in BSIs in patients with or without cancer in a 600-bed teaching community hospital.

We analysed all positive blood cultures from adult patients between January 2005 and January 2011.

A total of 4,918 episodes of BSI occurred in 2,891 patients, of whom 13.4% had a diagnosis of cancer (85.5% with a solid tumour). In both patient groups, Gram-positive isolates were more prevalent (58.7 and 61.4% in patients with and without cancer, respectively) than Gram-negative isolates (31.8 and 32.3%, respectively). Amongst Gram-positive organisms, coagulase-negative staphylococci, Staphylococcus aureus and enterococci were the most frequently isolated in both patient groups; in cancer patients, twice as many BSIs were caused by Enterococcus faecalis and E. faecium. Amongst Gram-negative organisms, Escherichia coli was the most common isolate; in cancer patients, twice as many BSIs were caused by Pseudomonas aeruginosa and Enterobacter cloacae. Yeasts were grown from 3.0% of blood cultures from cancer patients compared to 1.5% of cultures from non-cancer patients. Cancer patients had a 90-day mortality of 35.8% following BSI compared to 23.5% in patients without cancer.

These data demonstrate distinct BSI pathogens and impaired outcomes in patients with cancer in the setting of a large community teaching hospital.