Bacteremia In The Chronic Spinal Cord Injury Population: Risk Factors For Mortality

Abstract

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 3 2-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 (31 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 3 6 out of 63 patients, chronic ventilator dependency in 5 out of 63 patients, recent surgical procedures in 17 out of 63 patients, unde rlying malignancy in 5 out of 63 patients, and evidence of malnutrition in 2 9 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 1 0 additional participants, such that total mortality was 1 8 out of 63 (2 9%). The sources of bacteremia were urinary tract infection (n = 3 9), presumed contaminant (n = 28), decubitus ulcers (n = 21 ), intravascular catheter (n = 1 9), pneumonia (n = 5), and other (n = 11 ). Gram-negative rods accounted for 2 6 out of 3 9 episodes of bacteremia from a urinary source. Methicillin-resistant Staphylococcus au reus, methicillin-sensitiveS au reus, and coagulase-negative staphylococci were the predominant organi sms when intravascular catheters or pressure ulce rs 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 unde rlying debilitating conditions, particularly pressure ulcers. Chronic indwelling bladder cathet e rs and chronic vascular catheter usage also were highly prevalent in patients with bacteremic episodes. Hypoalbuminemia was the strongest independent predictor for mortality.