A large-scale survey of the postmortem human microbiome, and its potential to provide insight into the living health condition

Abstract

The microbiome plays many roles in human health, often through the exclusive lens of clinical interest. The inevitable end point for all living hosts, death, has its own altered microbiome configurations. However, little is understood about the ecology and changes of microbial communities after death, or their potential utility for understanding the health condition of the recently living. Here we reveal distinct postmortem microbiomes of human hosts from a large-scale survey of death cases representing a predominantly urban population, and demonstrated these microbiomes reflected antemortem health conditions within 24–48 hours of death. Our results characterized microbial community structure and predicted function from 188 cases representing a cross-section of an industrial-urban population. We found strong niche differentiation of anatomic habitat and microbial community turnover based on topographical distribution. Microbial community stability was documented up to two days after death. Additionally, we observed a positive relationship between cell motility and time since host death. Interestingly, we discovered evidence that microbial biodiversity is a predictor of antemortem host health condition (e.g., heart disease). These findings improve the understanding of postmortem host microbiota dynamics, and provide a robust dataset to test the postmortem microbiome as a tool for assessing health conditions in living populations.

Trace Evidence Potential in Postmortem Skin Microbiomes: From Death Scene to Morgue

“…To conclude, the current research contributes significantly to our understanding that human skin microbes can be used as trace evidence. These data show that individual microbiomes can persist into the early postmortem period, which is consistent with the observations of Pechal et al . The current findings also complement recent work demonstrating that antemortem skin microbial communities on humans resembled those of their phones and surfaces (e.g., door knobs, counters, and floors) in home and office environments.…”

“…It is difficult to assign a strict PMI to this event because process rates are influenced by myriad variables. However, recent research and the current study appear to indicate that relatively little change occurs during the initial 48 h postmortem. The investigation of unattended death scenes when PMI is greater than 1 day, however, may be better served by using skin microbiomes to estimate PMI.…”

An Experiment to Characterize the Decomposer Community Associated with Carcasses (Sus scrofa domesticus) on Oahu, Hawaii

“…Postmortem microbial communities, regardless of carcass species, are regularly dominated by bacteria from phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria (26)(27)(28)(29)(30)41) with other phyla such as Verrucomicrobia and Fusobacteria observed with some regularity (39,41,42). The current results complement these studies by demonstrating that bacteria from these same phyla can be cultured under aerobic and anaerobic conditions.…”

“…As observed by Chun et al (25), this habitat selected for a microbial community comprising phyla Firmicutes and Proteobacteria. These phyla are regularly associated with decomposing remains (26)(27)(28)(29)(30) and are likely reducing sulfur compounds to acquire energy (Fig. 6c).…”

“…These microbes contribute significantly to decomposition (e.g., putrefaction) and can release volatile organic compounds that attract insects and scavengers . Recent postmortem microbiology has demonstrated that bacterial phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria are regularly associated with decomposing remains regardless of carcass species, season, or soil type . However, despite the surge of interest in postmortem microbiology, few studies have investigated the microbial communities associated with insect larval masses.…”