Early post mortem interval estimation in a mouse model using molecular analyses of the gut thanatomicrobiome

Abstract

Introduction

Currently, the lack of reliable quantitative methods have led different research lines to find a model that predicts the post-mortem interval (PMI). The thanatomicrobiome, present from the moment of death, has been shown to change in predictable ways, allowing a correlation with PMI.

Materials and methods

In this study, the shifts of the thanatomicrobiome in the region of the posterior small intestine and the ascending colon in Mus musculus during the first 24 h of decomposition have been analysed experimentally. For this purpose, a molecular approach based on the analysis of the 16S ribosomal gene (16S rRNA) and a denaturing gradient gel electrophoresis (DGGE) was adopted, followed by analyses of the ecological diversity indices Alpha and beta diversity.

Results

The results based on the analysis of the ecological diversity indices reflected statistically significant changes before 12 h, and a decrease in diversity after 12 h post mortem, this being statistically significant in the two intestinal regions analysed. Moreover, the comparative study of microbial communities indicated distinct and structured changes from the moment of death, with shifts in the degree of similarity from the composition detected in life (PMI 0 h).

Discussion

These results agree with other studies demonstrating a decrease in microbial diversity. However, under the conditions of the study, this decrease does not begin until 12 h after death.

Conclusions

In conclusion, by examining the dynamics of bacterial diversity, our study has identified phases during decomposition that could help to improve microbial correlation models for PMI estimation.