Skin Microbiome May Help Identify Cause of Death

A novel multi-omics approach combining skin microbiome and metabolite analysis may improve forensic investigations by helping scientists distinguish between different causes of death and estimate postmortem interval (PMI), according to a new study.

Accurately determining both the cause of death and the time since death remains one of the greatest challenges in forensic science, particularly in cases where individuals die rapidly and show few obvious physical signs. Researchers have now demonstrated that changes in the skin microbiome and metabolic profiles following death may provide valuable forensic biomarkers.

The study investigated postmortem facial skin samples collected from mouse models of hemorrhagic shock and organophosphate poisoning—two causes of death that can present diagnostic challenges. Samples were analysed at three different stages of decomposition to identify microbial and metabolic changes over time.

Distinct Microbial Patterns Identified

Using metagenomic sequencing, researchers found significant differences in microbial diversity between the two causes of death throughout all stages of decomposition.

Hemorrhagic shock was associated with consistently lower microbial diversity compared with organophosphate poisoning. The composition of bacterial communities also differed substantially over time.

During the early bloating stage of decomposition, bacteria belonging to the Firmicutes phylum were more abundant in hemorrhagic shock, whereas Proteobacteria predominated in organophosphate poisoning. In total, 237 differentially abundant microbial taxa were identified.

The bacterial genera Providencia and Morganella were strongly associated with organophosphate poisoning, while Staphylococcus and Corynebacterium were particularly enriched during the early stages of hemorrhagic shock.

Metabolic Signatures Offer Additional Clues

Alongside microbial changes, metabolomic analyses revealed distinct metabolic signatures linked to both cause of death and postmortem interval.

Researchers identified elevated levels of 2′-deoxycytidine-5′-diphosphate during the early stages of organophosphate poisoning, while persistent accumulation of cholic acid and cholate was observed in hemorrhagic shock during later stages of decomposition.

Functional pathway analyses highlighted histidine metabolism and phosphate/phosphonate metabolism as key biological processes that varied between causes of death. These metabolic changes also demonstrated strong correlations with characteristic microbial taxa, suggesting that integrating microbiome and metabolome data may provide greater diagnostic accuracy than either approach alone.

Potential Applications in Forensic Science

The findings support the growing role of multi-omics technologies in forensic medicine. By examining both microbial succession and metabolic alterations over time, researchers were able to identify robust biomarkers associated with specific causes of death and different stages of decomposition.

Importantly, facial skin sampling represents a minimally invasive approach that may prove useful in forensic investigations where traditional methods are inconclusive.

Although the current study was conducted in animal models, the authors suggest that integrated skin microbiome–metabolome profiling could eventually become a valuable tool for forensic scientists seeking to improve postmortem interval estimation and cause-of-death determination.

Further validation in human studies will be necessary before the approach can be implemented in routine forensic practice, but the findings offer an intriguing glimpse into the future of forensic diagnostics.

Reference

Zhao J et al. Differentiating hemorrhagic shock and organophosphate poisoning through integrated skin microbiome–metabolome signatures. BMC Microbiol. 2026;DOI: 10.1186/s12866-026-05276-1