Pinpointing the time of death is one of the major priorities of a forensic scientist. There are many indicators such as body temperature, Rigor Mortis, and even by looking at what insects are on the body but now scientists are looking into how the bacteria in your mouth changes at different times after death.
The human body has an extensive bacterial assortment. The gastrointestinal tract take the cake for housing the most bacteria, but the mouth comes in a close second. The bacteria in the body is ultimately what contributes to the decomposition of the human body, but how does it change after we die? It turns out that different types of bacteria play a role in the different stages of decomposition. Researchers at the University of Girona studied the bacteria in 3 donated cadavers. By swabbing their mouths daily, they could look at the changes. They found that in the early stages of decomposition, Firmicutes and Antinobacteria are the most common because those are the bacteria that normally preside in our mouths. It would make sense as to why they are still there. During the bloating stage, Tenericutes are found to have taken over. Tenericutes are predominantly found in the gut but by day 5 of decomposition, they have made their way to the oral cavity due to . They are able to thrive in this stage due to their ability to use anaerobic fermentation of simple sugars for substrate level phosphorylation because by day 5 the body has used up all of its oxygen.
The researchers found that oxygen plays a major role in which bacteria are present during decomposition of the human body. By looking at changes in bacteria post mortem could offer a way for scientists to find a more accurate time of death. I do believe that a lot more research on this needs to be done.
Adserias-Garriga J., Quijada NM.,
Hernandez M., Rodríguez Lázaro D., Steadman D., Garcia-Gil J. (2017, June 23) Dynamics of the oral microbiota as a tool to estimate time
since death. Mol Oral Microbiol. 2017;00:1–6. https://doi.
org/10.1111/omi.12191
I am an intern at the Denver County Medical Examiner's Office. What I have seen from my experience there is that the doctors will measure the size of the larva and calculate the number of gestation periods which they have gone through to help determine the amount of time which these people have been dead. They measure this alongside looking at the decadents last point of contact mainly to determine the date an time of death. As mentioned in your synopsis, it would be interesting to see how measuring bacteria could offer the scientists a more accurate time of death. Are these scientists measuring just the different types of bacteria in the mouth or is the concentration of bacteria also playing a role in determining time of death? I am interested in seeing how the research on this topic progresses.
ReplyDeleteThis is interesting because it gives another way to estimate time of death. How long do the different bacterias live within the body? How long does it take for the bacteria to completely leave the body? How accurate are current methods of determining the time of death? Which technique would be the cheaper option?
ReplyDelete