Introduction: Blood Stream Infection (BSI) is a well known complication following trauma. However the timing of BSI, microbiology and its impact on outcome are not well described. The goal of this study was to examine the incidence, outcome and predictors of BSI in adult patients admitted to a level-I urban Trauma Center.

Methods: Retrospective review of trauma patients who developed a BSI was performed from 1/07 to 12/08. Patients were excluded if they were discharged within 24 hours of admission. Demographic data, injury severity, transfusion requirements and microbiology were reviewed. Outcome included ICU and hospital length of stay (LOS), ventilator days and death. A student t-test, chi-square test or a Wilcoxon rank-sum test was used as appropriate.

Results: 2055 adult patients were admitted during a 48-month period. 66 patients (3%) sustained 105 episodes of BSI, 62 (59%) were GM (+), 38 (36%) were GM (-) and 5 were (5%) Fungi. The most common pathogen was a Coagulase (-) Staph. Aureus. No identifiable source occurred in 41/105 (39%) episode of BSI, in remaining 64 the source of infection was the lung (33%), central line (24%), abdomen (20%), soft tissue (14%), urine (6%), others (3%). Time of the first BSI was 16 days ± 21 (median 8 days) with 31(46%) of the initial BSI occurring the first week following injury. Patients with a BSI had a higher mean ISS (26 ± 11. vs. 15 ± 19, p=0.001), higher mean # of units of PRBCs transfused (22 ±27.4 vs. 6±7.4 p=0.001). There was no difference in age or gender between both groups. Patients with a BSI had a higher mortality (15% versus 4%, p<0.0001), hospital LOS (50±49 vs. 10± 14, p = 0.001), ICU LOS (24 ±17 vs. 8 ± 8, p=0.001) as well as vent days (22.1 ±16.3 vs. 6.7 ±7.4, p=0.001). Logistic regression revealed that BSI was not an independent predictor of death. Multiple episodes of BSI were seen in 21 patients.

	No-BSI	Single BSI	Multiple BSI
N (%)	1989 (97%)	45 (2%)	21(1%)
Age	42 ± 19	41 ±19	40± 14
ISS	14.5 ± 10*	24 ±11	30 ±10
Mortality	4%**	13%	19%
H LOS	10 ± 14*	41 ± 40	70 ± 61

p=0.001*, p<0.0001** vs. patients with BSI

Conclusion: Incidence of BSI in trauma patients was 3%. BSI was more frequently seen in patients with higher ISS and higher transfusion requirements. Mean time to develop a BSI was 2 weeks, however half occurred in the first week following trauma. Patients who developed a BSI had higher mortality, longer vent days, ICU and hospital stay, but BSI was not an independent predictor of death. Gram-positive microorganisms were responsible for more than half of all BSI and Staphylococcus Aureus was the most common pathogen. More than half of BSI had an identifiable source and in this group the 3 most common sources are lungs, central line and abdomen. Although BSI did not influence mortality we believe it’s a marker for impaired immunity rather than a primary cause of mortality.