Bacteremia in the chronic spinal cord injury population: Risk factors for mortality

Background: Individuals with spinal cord injury (SCI) have a lifelong increased risk of systemic infection, which may be associated with episodes of life-threatening bacteremia. Information concerning specific organisms causing bacteremia, the sites of primary infection, and clinical predictors for mortality are necessary to provide optimal treatment. Methods: A retrospective review of positive blood cultures collected over a 32-month period in chronic SCI patients treated at the Veterans Affairs Medical Center SCI Unit. Results: One hundred and twenty-three episodes of bacteremia occurred in 63 patients during 83 hospitalizations; 30 patients had multiple episodes of bacteremia. There were 1,644 admissions during this period, yielding an incidence of bacteremia of 7.5% (5.8% after excluding positive cultures that were believed to be caused by contaminants). The patients (3 1 with paraplegia and 32 with quadriplegia) had a mean age of 59 +/- 2 years, and a mean duration of injury of 23 2 years. Bladder management technique consisted of indwelling bladder catheter (n = 53), ileal conduit (n = 6), intermittent catheterization (n = 2), and spontaneous voiding (n = 2). Episodes of bacteremia were nosocomial in 89 out of 123 episodes. Multiple debilitating factors were present, including pressure ulcers in 36 out of 63 patients, chronic ventilator dependency in 5 out of 63 patients, recent surgical procedures in 17 out of 63 patients, underlying malignancy in 5 out of 63 patients, and evidence of malnutrition in 29 out of 63 patients (serum albumin concentration < 2.5 g/dL). Early mortality rate (death within 30 days of bacteremia) occurred in 8 out of 63 patients (13%) and late mortality (> 1 month following a bacteremic episode) occurred in 10 additional participants, such that total mortality was 18 out of 63 (29%). The sources of bacteremia were urinary tract infection (n = 39), presumed contaminant (n = 2 8), decubitus ulcers (n = 2 1), intravascular catheter (n = 19), pneumonia (n = 5), and other (n = I I). Gram-negative rods accounted for 26 out of 39 episodes of bacteremia from a urinary source. Methicillin-resistant Staphylococcus aureus, methicillin-sensitive S aureus, and coagulase-negative staphylococci were the predominant organisms when intravascular catheters or pressure ulcers were the source of bacteremia. Conclusion: In this population, bacteremia predominantly was caused by hospital-associated organisms, and occurred mainly in malnourished patients who required hospitalization for major underlying debilitating conditions, particularly pressure ulcers. Chronic indwelling bladder catheters and chronic vascular catheter usage also were highly prevalent in patients with bacteremic episodes. Hypoalbuminemia was the strongest independent predictor for mortality.