Microbial neoformation of volatiles: implications for the estimation of post-mortem interval in decomposed human remains in an indoor setting

Abstract

The objective of this study was to determine if a relationship between microbial neoformation of volatiles and the post-mortem interval (PMI) exists, and if the volatiles could be used as a tool to improve the precision of PMI estimation in decomposed human remains found in an indoor setting. Chromatograms from alcohol analysis (femoral vein blood) of 412 cases were retrospectively assessed for the presence of ethanol, N-propanol, 1-butanol, and acetaldehyde. The most common finding was acetaldehyde (83% of the cases), followed by ethanol (37%), N-propanol (21%), and 1-butanol (4%). A direct link between the volatiles and the PMI or the degree of decomposition was not observed. However, the decomposition had progressed faster in cases with microbial neoformation than in cases without signs of neoformation. Microbial neoformation may therefore act as an indicator of the decomposition rate within the early decomposition to bloating stages. This may be used in PMI estimation based on the total body score (TBS) and accumulated degree days (ADD) model, to potentially improve the model’s precision.

A synthesis of carcass decomposition studies conducted at a tropical (Aw) taphonomy facility: 2013–2022

“…Medicolegal decomposition cases with a known PMI can be used to develop a database for human remains in forensic scenarios. Retrospective and real-time decomposition studies conducted in collaboration with medicolegal death investigation agencies provide valuable insight into the taphonomy within a given jurisdiction, particularly in built environments [ 14 , 42 , 43 , 56 , [100] , [101] , [102] , [103] , [104] , [105] , [106] , [107] ]. These data will likely provide investigators with an improved ability to determine if the extent of decomposition is consistent with the scene findings.…”

Development and implementation of forensic anthropology in Swedish forensic practice

“…A discussion and a final decision has yet to take place on this matter. In terms of research, Sweden based researchers are engaging in forensicanthropological and forensic-taphonomic research [1,4,28,[39][40][41][42][43][44][45][46][47][48][49][50][51][52]. This is in addition to a long tradition of osteoarchaeological research, including forensic-anthropology-relevant skeletal research into, for example, traumatic injuries versus taphonomic skeletal alterations [53].…”

Ethanol and Higher Alcohols’ Production in Fungal and Bacterial Laboratory Cultures and Significance for Forensic Samples

“…To achieve a feasible accuracy in interpreting the postmortem ethanol analysis results and in defining the origin (whether it is a result of antemortem consumption or postmortem microbial production or both) of the measured ethanol, various factors have been evaluated [ 5 , 10 , 11 ], such as the putrefaction state of the cadaver at autopsy, the clinical history of the deceased, the determination of non-oxidative metabolites of ethanol, the identification of microbes in the analyzed sample, and the evaluation of the discrepancies between ethanol concentration from various sampling sites and from different specimens [ 5 , 12 , 13 , 14 , 15 , 16 , 17 ]. Furthermore, the detection of low-molecular-weight volatiles in postmortem specimens was related to the microbial ethanol neo-formation [ 18 , 19 , 20 , 21 , 22 , 23 ]. Specifically, the volatile compounds known as higher, or congener, alcohols—referring mainly to 1-propanol (or n-propanol), isobutanol (or methyl-1-propanol), 2- methyl-1-butanol (or isoamyl-alcohol), 3-methyl-2-butanol (or amyl-alcohol), and 1-butanol (or n-butanol)—are often detected in postmortem specimens [ 24 , 25 , 26 ], and their presence is considered indicative of putrefaction and microbial activity [ 18 , 27 ].…”