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Updated: Jun 13, 2025
A Controlled Mouse Model for Neonatal Polymicrobial Sepsis
Published on: January 27, 2019
Seasonal mouse cadaver microbial study: rupture time and postmortem interval estimation model construction
Xingchun Zhao1,2, Fengqin Yang3, Fan Yang1,2
1Institute of Forensic Science, Ministry of Public Security, Beijing, China.
Abstract:
The estimation of postmortem interval (PMI) has long been a focal point in the field of forensic science. Following the death of an organism, microorganisms exhibit a clock-like proliferation pattern during the course of cadaver decomposition, forming the foundation for utilizing microbiology in PMI estimation. The establishment of PMI estimation models based on datasets from different seasons is of great practical significance. In this experiment, we conducted microbiota sequencing and analysis on gravesoil and mouse intestinal contents collected during both the winter and summer seasons and constructed a PMI estimation model using the Random Forest algorithm. The results showed that the MAE of the gut microbiota model in summer was 0.47 ± 0.26 d, R2 = 0.991, and the MAE of the gravesoil model in winter was 1.04 ± 0.22 d, R2 = 0.998. We propose that, in practical applications, it is advantageous to selectively build PMI estimation models based on seasonal variations. Additionally, through a combination of morphological observations, gravesoil microbiota sequencing results, and soil physicochemical data, we identified the time of cadaveric rupture for mouse cadavers, occurring at around days 24-27 in winter and days 6-9 in summer. This study not only confirms previous research findings but also introduces novel insights, contributing to the foundational knowledge necessary to advance the utilization of microbiota for PMI estimation.
Insights
Microbial analysis of gravesoil and gut contents can estimate the postmortem interval (PMI). Seasonal models, particularly for gut microbiota in summer, provide accurate PMI estimations, aiding forensic science investigations.
Area of Science:
- Forensic microbiology
- Decomposition science
Background:
- Estimating the postmortem interval (PMI) is crucial in forensic science.
- Cadaver decomposition involves predictable microbial proliferation patterns.
- Seasonal variations impact decomposition rates and microbial communities.
Purpose of the Study:
- To develop and validate seasonal postmortem interval (PMI) estimation models using microbiota.
- To investigate the influence of season on gravesoil and gut microbial communities during decomposition.
- To identify the timing of cadaveric rupture based on microbial and environmental factors.
Main Methods:
- Microbiota sequencing and analysis of mouse intestinal contents and gravesoil.
- Development of a PMI estimation model using the Random Forest algorithm.
- Integration of morphological observations and soil physicochemical data.
Main Results:
- Summer gut microbiota model achieved a Mean Absolute Error (MAE) of 0.47 ± 0.26 days (R² = 0.991).
- Winter gravesoil microbiota model achieved an MAE of 1.04 ± 0.22 days (R² = 0.998).
- Cadaveric rupture occurred around 6–9 days in summer and 24–27 days in winter.
Conclusions:
- Seasonal PMI estimation models are advantageous for practical forensic applications.
- Microbiota analysis offers a robust method for PMI estimation, adaptable to seasonal conditions.
- This study enhances the foundational knowledge for microbial utilization in forensic investigations.
