Dissecting the Microbial Community Structure of Internal Organs During the Early Postmortem Period in a Murine Corpse Model

Abstract

Background Microorganisms inhabit and proliferate throughout the body both externally and internally, which are the primary mediators of putrefaction after death. However, limited information is available about the changes in the postmortem microbiota of extraintestinal body sites in the early decomposition stage of mammalian corpses. Results This study applied 16S rRNA barcoding to investigate microbial composition variations among different organs and the relationship between microbial communities and time since death over 1 day of decomposition. During 1 day of decomposition, Agrobacterium, Prevotella, Bacillus, and Turicibacter were regarded as time-relevant genera in internal organs at different timepoints. Pathways associated with lipid, amino acid, carbohydrate and terpenoid and polyketide metabolism were significantly enriched at 8 hours than that at 0.5 or 4 hours. The microbiome compositions and postmortem metabolic pathways differed by time since death, and more importantly, these alterations were organ specific. Conclusion The dominant microbes differed by organ, while they tended toward similarity as decomposition progressed. The observed thanatomicrobiome variation by body site provides new knowledge into decomposition ecology and forensic microbiology. Additionally, the microbes detected at 0.5 hours in internal organs may inform a new direction for organ transplantation.