A microbial clock provides an accurate estimate of the postmortem interval in a mouse model system

Abstract

Establishing the time since death is critical in every death investigation, yet existing techniques are susceptible to a range of errors and biases. For example, forensic entomology is widely used to assess the postmortem interval (PMI), but errors can range from days to months. Microbes may provide a novel method for estimating PMI that avoids many of these limitations. Here we show that postmortem microbial community changes are dramatic, measurable, and repeatable in a mouse model system, allowing PMI to be estimated within approximately 3 days over 48 days. Our results provide a detailed understanding of bacterial and microbial eukaryotic ecology within a decomposing corpse system and suggest that microbial community data can be developed into a forensic tool for estimating PMI.DOI: http://dx.doi.org/10.7554/eLife.01104.001

Shifts in soil biodiversity—A forensic comparison between Sus scrofa domesticus and vegetation decomposition

“…Studies of cadaver decomposition and its interactions with, and effects on, soil ecology have highlighted the potential of forensic ecogenomics as a powerful tool to estimate PMI and identify clandestine graves through changes in microbial communities [14][15][16][20][21][22][23]. Although this tool has potential advantages compared with conventional methods for estimating PMI, most studies have, however, only considered a single carbon source (the cadaver) while dual sources can provide useful information for forensic practitioners to identify and differentiate gravesites in difficult cases such as transit or clandestine scenarios.…”

“…The application of fatty acid-based techniques, such as phospholipid fatty acid and fatty acid methyl ester analyses, and molecular techniques, such as polymerase chain reaction (PCR), denaturing/temperature gradient gel electrophoresis (T/DGGE) and terminal restriction length polymorphism (T-RFLP) with next generation sequencing for microbial community profiling, are beginning to elucidate the complex relationships between cadaver decomposition, nutrient cycling and soil microbial community dynamics in a forensic context [6,[13][14][15][16][17][18]. For example, some sub-surface studies by Bergmann et al [19] and Olakanye et al [20] recorded spatial and temporal changes in soil bacterial diversity relative to burial depth and decomposition time, respectively.…”

“…Also, aboveground studies by Lauber et al [21] that investigated the roles of microorganisms in cadaver ecogenomics recorded changes in 16S rRNA bacterial, 16S rRNA archaeal, and 18S rRNA fungal communities in sterile and non-sterile soils with differences between skin-associated and grave soil during the active and advanced decay stages. Thus, several researchers have illustrated and suggested that changes in epinecrotic and burial soil microbial diversity can be a potential "post-mortem microbial clock" tool for PMI estimation [15,16].…”

Changes to soil bacterial profiles as a result of Sus scrofa domesticus decomposition

“…Extraction of nucleic acids from microbial cells in soil samples by molecular techniques and their various applications in polymerase chain reaction (PCR) amplification and hybridization experiments has allowed researchers to identify and characterise numerous microorganisms in different environments [5,6]. The importance of cadaver decomposition knowledge cannot be over emphasized hence emergent studies have analysed changes in the postmortem microbiome or necrobiome of the abdominal, interior anal and buccal cavities and skin of decomposing carcasses [7][8][9][10]. Nonetheless, the majority of research has focused on above ground decomposition [6,[11][12][13].…”

Adli bilimlerde entomolojinin uygulanması

“…Microbes play a major role in the decomposition process and changing microbial communities present during decomposition of body have the potential to be used to establish a "postmortem microbial clock. Recent studies suggest that microbial analysis can provide a reliable estimation for PMI, or time since death (Metcalf et al, 2013) …”