New research conducted by researchers at Sam Houston State University and Baylor College of Medicine revealed that bacterial communities around a corpse could change overtime as human decomposition progresses. The study has appeared on October 30th in the open-access journal PLOS ONE, titled “The Living Dead: Bacterial Community Structure of a Cadaver at the Onset and End of the Bloat Stage of Decomposition.”
Understanding the factors involved in decomposition of a corpse is critical in forensics to determine postmortem interval (PMI - the time since death), however, few studies have catalogued bacterial biodiversity at decomposition process.
In the study led by Aaron Lynne, two donated human cadavers were placed under natural conditions in an outdoor facility at the Southeast Texas Applied Forensic Science (STAFS). They took samples in all body sites, including inside of the body, at the onset and the end of bloat stage of decomposition and assessed bacterial biodiversity using a gene sequencing method to analyze bacterial DNA.
They found that the bacterial communities were different between the two bodies, between regions on the same body, and among time of decomposition. The authors suggest that bacterial communities might be following specific, changing patterns as a corpse moves through its natural stages of decomposition.
“This study is the first to catalogue bacteria present internally at the onset and end of the bloat stage of human decomposition. Ultimately, we hope to come up with a cumulative systems approach to look at decomposition in a way that might complement existing forensic models at determining PMI,” said Lynne.