MALDI-TOF Mass Spectrometry Analysis and Human Post-Mortem Microbial Community: A Pilot Study.

Area of Science:

• Forensic microbiology
• Microbial ecology
• Biotechnology

Background:

• The human post-mortem microbiome (HPM) significantly influences decomposition.
• High-throughput sequencing has shown HPM bacterial communities can predict post-mortem interval (PMI).
• Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) offers a rapid and cost-effective method for microbial identification.

Purpose of the Study:

• To evaluate MALDI-TOF MS as a tool for identifying microbes in the HPM.
• To assess the utility of MALDI-TOF MS for studying HPM changes over time.
• To determine if MALDI-TOF MS can aid in PMI estimation.

Main Methods:

• 18 human bodies with post-mortem intervals (PMI) ranging from 24 hours to 15 days were studied.
• Microbiological swabs were collected from five external sites and four internal organs.
• MALDI-TOF MS was used for microbial taxonomic identification.

Main Results:

• The HPM composition shifted significantly over time in both internal organs and skin sites.
• Firmicutes and Proteobacteria were the dominant phyla in the HPM.
• A distinct microbial turnover was observed during decomposition, correlating with PMI.

Conclusions:

• MALDI-TOF MS is a viable, high-throughput method for HPM analysis and PMI estimation due to its speed and reproducibility.
• The technique can detect overall microbial community shifts in prevalent phyla during decomposition.
• Limitations include sensitivity issues inherent to culture-dependent methods and potential bias in identifying novel microbial isolates.