Recurrent gram-negative bacteremia

Recurrent gram-negative bacteremia is defined as two or more episodes of bacteremia occurring in the same patient with an infection-free interval between each episode. Our purpose was to identify patients with recurrent gram-negative bacteremia in order to define possible risk factors for its recurrence.

During a recently completed prospective study of all episodes of gram-negative bacteremia at the Buffalo Veterans Administration Center between April 1, 1984, and May 31, 1987, 35 patients with 74 episodes of gram-negative bacteremia were identified. The following information was obtained from all 35 patients: age, service, date of hospital admission, date of the bacteremia, underlying diseases, initial antimicrobial therapy, focus of infection, the presence or absence of shock, antimicrobial susceptibility of the blood isolate, and outcome.

All 35 patients were men, had a mean age of 69 years, and all had one or more underlying diseases; 45 percent had a malignancy. The duration of time between a pair of episodes was four weeks or more for 74 percent of 38 pairs of episodes. In 25 of 38 (66 percent) pairs of episodes, the focus of infection was the same; in 80 percent of these 25 pairs, the urinary tract was the focus. Overall, the urinary tract was the focus of gram-negative bacteremia in almost 50 percent. Escherichia coli was the single most common organism isolated (28 percent of all episodes), followed by Proteus mirabilis (17.5 percent) and Pseudomonas aeruginosa (17.5 percent). Six of 35 (17 percent) patients died due to gram-negative bacteremia; five of these six had a respiratory tract focus of infection.

In a population of veterans, recurrent gram-negative bacteremia was identified in almost 10 percent of all patients with gram-negative bacteremia during a 37-month study period. Recurrent gram-negative bacteremia most frequently occurred in the setting of underlying malignancy with the urinary tract as a common focus of infection. The mortality rate of 17 percent was similar to that of all patients with gram-negative bacteremia reported in previous studies.