Polytrauma independent of therapeutic intervention alters the gastrointestinal microbiome

Background: This study characterizes the gastrointestinal (GI) microbiome in a pre-clinical polytrauma hemorrhage model. Methods: Rats (n = 6) were anesthetized, hemorrhaged 20% of their blood volume, and subjected to a femur fracture and crush injuries to the small intestine, liver, and limb skeletal muscle without resuscitation. Fecal samples were collected pre-injury and 2 h post-injury. Purified DNA from the samples underwent 16s rRNA sequencing for microbial quantification. Bacterial diversity analysis and taxonomic classification were performed. Results: Following injury, the gut microbial composition was altered with a shift in beta diversity and significant differences in the relative abundance of taxa. The relative abundance of the families Lachnospiraceae and Mogibacteriaceae was increased at 2 h, while Barnesiellaceae and Bacteroidaceae were decreased. Alpha diversity was unchanged. Conclusions: The GI microbiome is altered in rats subjected to a polytrauma hemorrhage model at 2 h post-injury in the absence of antibiotics or therapeutic interventions. This study demonstrates that the GI microbiome is altered 2 h post-injury in a pre-clinical polytrauma hemorrhage rat model in the absence of therapeutic intervention. While species number or diversity remained similar post-injury, a dysbiosis in microbial composition occurred at this early time point with changes seen in several bacterial families.