Potential postmortem microbial biomarkers of infant and younger children death investigation

Microbial communities associated with the human body are highly dynamic and reflect the host environment and lifestyle over time. Studies show death is no exception, with data demonstrating similar antemortem and postmortem microbiomes up to 48 h following death. These predictable microbial biomarkers can inform death investigation by helping to estimate the postmortem interval and build models to identify cause and manner of death. However, no attempts have been made to model potential microbial biomarkers in pediatric (≤2 years) deaths. This study provided a cross-sectional survey of the microbiota of 53 pediatric cases (black, white, both sexes) seen in Wayne County, Michigan. Autopsy cases represented accidents, homicides, or natural causes. Postmortem microbiome were collected by swabbing the eyes, ears, nose, mouth, umbilicus, brain, rectum, trabecular space, and cardiac blood. 16S rRNA sequence analyses indicated that sex, race, age, body site, and manner of death (MOD) had significant effects on microbiome composition, with significant interactions among MOD, race, and age. Amplicon sequence variants identified intra- and interhost dispersion of the postmortem microbiome depending on death circumstance. Among manners of death, non-accidental deaths were significantly distinct from all other deaths, and among body sites the rectum was distinct in its microbial composition. There is a real need for robust postmortem microbiome before it can be standardized as a practical tool for use in forensic investigation or public health. These results inform postmortem microbial variability during pediatric death investigation that contributes to a larger effort to understand the postmortem microbiome.