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Estimating Time Since Death from Postmortem Human Gut Microbial Communities
Author(s) -
Hauther Kathleen A.,
Cobaugh Kelly L.,
Jantz Lee Meadows,
Sparer Tim E.,
DeBruyn Jennifer M.
Publication year - 2015
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/1556-4029.12828
Subject(s) - bacteroides , bifidobacterium , relative species abundance , biology , postmortem changes , microbiome , 16s ribosomal rna , microbiology and biotechnology , gut flora , human microbiome , lactobacillus , abundance (ecology) , bacteria , medicine , ecology , pathology , immunology , bioinformatics , genetics
Postmortem succession of human‐associated microbial communities (“human microbiome”) has been suggested as a possible method for estimating postmortem interval (PMI) for forensic analyses. Here we evaluate human gut bacterial populations to determine quantifiable, time‐dependent changes postmortem. Gut microflora were repeatedly sampled from the proximal large intestine of 12 deceased human individuals as they decayed under environmental conditions. Three intestinal bacterial genera were quantified by quantitative PCR (qPCR) using group‐specific primers targeting 16S rRNA genes. Bacteroides and Lactobacillus relative abundances declined exponentially with increasing PMI at rates of N t = 0.977e −0.0144 t ( r 2 = 0.537, p < 0.001) and N t = 0.019e −0.0087 t ( r 2 = 0.396, p < 0.001), respectively, where N t is relative abundance at time ( t ) in cumulative degree hours. Bifidobacterium relative abundances did not change significantly: N t = 0.003e −0.002 t ( r 2 = 0.033, p = 0.284). Therefore, Bacteroides and Lactobacillus abundances could be used as quantitative indicators of PMI.