The exploration of using gut microbiota to estimate early post-mortem interval

The precise estimation of early post-mortem interval (PMI) remains a significant challenge in forensic medicine. The gut microbiota, with its successional changes after host death, has emerged as a promising tool for forensic science. In this pilot study, we aimed to characterize the successional patterns of the cecal microbiota in rats during the first 24 h post-mortem using 16S rDNA amplicon sequencing, based on a small sample size (n = 3 per group). Our results indicated that, although overall microbial diversity remained largely stable, the community structure showed gradual temporal shifts over the 24 h period. Notably, we observed significant shifts in specific bacterial taxa, including a decline in Lactobacillus and an increase in Lachnospiraceae_NK4A136_group, although these findings are constrained by limited sample size and require confirmation in larger cohorts. Furthermore, Linear Discriminant Analysis Effect Size (LEfSe) identified 15 bacterial clades as potential differential biomarkers across the post-mortem intervals. Analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) suggested temporal shifts in microbial metabolic potential. Collectively, these preliminary findings suggest an association between the composition of the gut microbiota and early PMI, highlighting the potential of this approach as a basis for novel forensic indicators, pending further validation.