Succession of oral microbiota community as a tool to estimate postmortem interval

Abstract

The establishment of postmortem interval is one of the most important aspects of forensic expertise. Microbes may provide a novel way to estimate the postmortem intervals in order to avoid many of these limitations. The oral cavity harbors one of the most diverse microbiomes that play a key role in the decomposition of corpses. In this study, the oral bacterial community showed obvious changes in relative abundance during the process of mice decomposition. Meanwhile, at different taxonomic levels, specific bacteria were found to be significantly correlated with the postmortem interval. Linear regression models between relative abundance and the postmortem interval were constructed. Among these species, Gamma-proteobacteria and Proteus were the best ones that can be used to infer the postmortem interval, especially late postmortem interval. Therefore, we suggest that succession of oral microbial community can be developed as a forensic tool for estimating the postmortem interval.

Microbiome in Death and Beyond: Current Vistas and Future Trends

“…Within 10 days after death, Proteobacteria and Firmicutes dominate, with γ-Proteobacteria showing a strong positive linear correlation with PMI. At the family and genus levels, the relative abundance of Enterobacteriaceae and Proteus increased with an increase in PMI (Dong et al, 2019). Furthermore, the postmortem microbiome in 20 Dutch rabbits showed organ-and temperature-specific changes in the community, which is in line with the findings in human cadavers.…”

“…Many research groups have employed animal models such as swine (Dickson et al, 2011) and mice models (Dong et al, 2019) (Table 3), as these are similar to human bodies to the extent that they can provide a better understanding of the decomposition process in humans whereas being more readily available at the same time compared to human bodies (Javan et al, 2016a;Zhou and Bian, 2018). They are also low in cost compared to carrying out experiments on human cadavers.…”

Analysis of Microbial Communities: An Emerging Tool in Forensic Sciences

“…PMI is often difficult to establish because death mechanisms are very complex [ 3 ]. After death, the body undergoes irreversible, gradual physical and chemical changes [ 56 ]. This organic matter decomposition, especially cadaver decomposition, engages biological factors like cell enzymes, bacteria, fungi, protozoa, insects or carnivores, and non-biological factors linked to the environment such as humidity or weather [ 57 ].…”

“…Many environmental factors such as temperature, grave soil, humidity, oxygen, precipitation, and presence of insects or scavenger animals can influence this sequencing decomposition of a microbiome [ 56 , 59 ]. The soil decomposition is linked to the microbial activity.…”

Determinação Do Intervalo De Pós-Morte De Cadáveres: Impasses Encontrados Nas Técnicas Utilizadas Pela Perícia Forense

“…Sendo assim, os métodos que interferem as estimativas de IPM são difíceis de serem estabelecidos, pois são suscetíveis a muitos fatores externos e ambientais, como temperatura, umidade, tensão de oxigênio, insetos e atividade necrófaga (DONG et al, 2019). Ferreira;Cunha (2012) relatam que pode ocorrer variabilidade no tempo de decomposição em indivíduos que possuem o mesmo período de pós morte, sendo assim, as estimativas devem levar em considerações as condições específicas de cada situação.…”