• Jennifer A Munley, Lauren S Kelly, Gwoncheol Park, Erick E Pons, Kolenkode B Kannan, Letita E Bible, Philip A Efron, Ravinder Nagpal, and Alicia M Mohr.
• Department of Surgery and Sepsis and Critical Illness Research Center, University of Florida College of Medicine, Gainesville, Florida.
• Shock. 2024 Aug 8.

BackgroundPrevious preclinical studies have demonstrated a pathobiome after traumatic injury; however, the impact of post-injury sepsis on gut epithelial permeability and bacterial translocation remains unknown. We hypothesized that polytrauma with post-injury pneumonia would result in impaired gut permeability leading to specific blood microbiome arrays.MethodsMale and proestrus female Sprague-Dawley rats were subjected to either polytrauma (PT), PT plus 2-hours daily chronic restraint stress (PT/CS), PT with postinjury day 1 inoculation with pseudomonas pneumonia (PT + PNA), PT/CS + PNA, or naive controls. Whole blood microbiome was measured serially using high-throughput 16S rRNA sequencing and QIIME2 bioinformatics analyses. Microbial diversity was assessed using Chao1/Shannon indices and principle coordinate analysis. Intestinal permeability was evaluated by plasma occludin and lipopolysaccharide-binding protein (LBP) assays.ResultsPT/CS + PNA had increased intestinal permeability compared to uninfected counterparts (PT/CS) with significantly elevated occludin (p < 0.01). Bacteria was not detected in the blood of naïve controls, PT or PT/CS, but was present in both PT + PNA and PT/CS + PNA on days two and seven. The PT/CS + PNA blood biome showed dominance of Streptococcus compared to PT + PNA at day two (p < 0.05). Females PT/CS + PNA had a significant abundance of Staphylococcus at day two and Streptococcus at day seven in the blood biome compared to male counterparts (p < 0.05).ConclusionsMulticompartmental trauma with post-injury pneumonia results in increased intestinal permeability and bacteremia with a unique blood biome, with sexual dimorphisms evident in the blood biome composition. These findings suggest that post-injury sepsis has clinical significance and could influence outcomes after severe trauma and critical illness.Copyright © 2024 by the Shock Society.

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