The investigators hypothesize that alterations of the gut microbiota will correlate with persistent systemic inflammation in sepsis and trauma survivors compared to existing healthy population controls. This research group will collect stool samples from 108 sepsis survivors and 108 trauma survivors (groups of ages 18-45, 46-64, and >65; male and female; n=18 per age + sex cohort) admitted to the surgical intensive care unit between day 7 and 28 of hospital admission, as well as 3 and 6 months after their sepsis or trauma event. The investigators will perform 16S rRNA DNA sequencing on the isolated bacterial DNA from these samples and bioinformatic analysis to determine microbiota alterations between time points and between sepsis and control cohorts. In addition, the investigators will draw 20ml of blood to isolate plasma.~Trauma Subgroup for traumatic brain injury (TBI) pilot study: Our team will enroll 15 additional trauma injury patients with traumatic brain injury. This subgroup will have an added stool (if available) and blood sample collection after initial injury (+ 5 days). The additional sample will be compared to the sample collected at 14-21 days and follow up samples at 3 and 6 months. The results will be associated with Glasgow Outcome Scale Extended at 3 and 12 month time points and the recorded discharge Rancho Los Amigos scale score from the medical record. The specific aims will be: Aim 1 - define the impact of persistent systemic inflammation on the gastrointestinal microbiota in sepsis and trauma survivors and Aim 2 - identify microbial genes associated with persistent systemic inflammation in sepsis and trauma survivors compared to normal controls. Trauma Subgroup Aim: Pilot study to test the hypothesis that changes in the microbiome towards pathogenic microbe is associated with worsened outcomes in trauma injury patients with TBI (traumatic brain injury).
Gastrointestinal microbiome dysfunction has been demonstrated to be a culprit of various systemic dysfunctions in peripheries such as cardiovascular, nervous, endocrine and musculoskeletal systems. The topic of microbiome dysfunction after sepsis and trauma injury is understudied but may be responsible for persistent systemic inflammation clinically observed in sepsis and trauma survivors. Therefore, the objective of this project is to investigate the gut microbiome after acute phase of sepsis or severe trauma injury and compare it with 108 age-matched healthy population controls