A review of the microbiome associated with human decomposition

The decomposition of human remains involves a complex microbial ecology that few studies have examined in depth. This review investigated the microbiome of human decomposition to further understand their functions within the decomposition process and their potential to increase the accuracy of post-mortem interval (PMI) estimations in forensic applications. The aims of the literature review were to (1) identify the external microbiome responsible for human decomposition, focusing on insect, soil and skin sources, (2) determine the roles of external bacteria in the various stages of human decomposition and (3) to analyse and compare the current contributions of literature in furthering the understanding of the ecological mosaic of decomposition. The current literature was reviewed and their contributions to necrobiome research was analysed using qualitative and contemporary research techniques. Bacteria were found to play a significant role in each stage of human decomposition with multiple studies demonstrating an observable successive shift in microbial communities through time. This change in community profile was found to be an important biomarker for the estimation of the PMI and potential substitute for entomological techniques currently utilised in forensic investigations. High interpersonal variation between decomposition events, in addition to narrow geographic specificity, represented limitations in the studies which may be remedied by increasing sample size while focusing on different geographic regions and environmental conditions