The microbiology of death.

The main aim of this research was an attempt to clarify whether the protagonists of bacterial bone destruction were of a bodily origin as opposed to environmental contamination by soil bacteria and furthermore to demonstrate a time frame for such attack. It is hypothesised that bacteria from the gut commensal flora are responsible for micro-focal destruction (MFD) of bone postmortem that leaves distinctive tunnels. Microorganisms live with a person throughout their life and somewhat ironically after death persist to exploit this now nonoperational substrate. They continue to thrive and without a working immune system are capable of crossing mucosal barriers and invading both soft and hard body tissues. Experimental protocol using pigs as human analogues were combined with archaeological sections of both humans and animals. The experimental research was almost absolute in the conclusion that only the fetal material was free of MFD one year post-mortem; these were entirely skeletonised and open to contamination by soil bacteria. All of the other pigs had suffered some form of attack, including those that had not skeletonised and were not therefore subjected to soil bacteria. The archaeological material tended to support the hypothesis that endogenous gut bacteria were the cause of MFD as both fetal material and animal bones were much less likely to be affected. It is suggested that soil bacteria are not normally accountable for MFD although their involvement cannot be ruled out entirely and they may be involved at a later stage. It is therefore likely that endogenous gut bacteria having access to a dead body immediately are most often the cause of MFD and that this occurs well within the early postmortem period. This has negative implications for biomolecular studies and positive implications for in-situ preservation.