Chun Lauren P, Miguel Marcus J, Junkins Emily N, Forbes Shari L, Carter David O
Laboratory of Forensic Taphonomy, Forensic Sciences Unit, Division of Natural Sciences and Mathematics, Chaminade University of Honolulu, Honolulu, HI 96816, USA.
Centre for Forensic Science, University of Technology Sydney, Broadway NSW, Australia.
Sci Justice. 2015 Dec;55(6):394-401. doi: 10.1016/j.scijus.2015.07.003. Epub 2015 Aug 15.
Postmortem microorganisms are increasingly recognized for their potential to serve as physical evidence. Yet, we still understand little about the ecology of postmortem microbes, particularly those associated with the skin and larval masses. We conducted an experiment to characterize microbiological and chemical properties of decomposing swine (Sus scrofa domesticus) carcasses on the island of Oahu, Hawaii, USA, during June 2013. Bacteria were collected from the head, limb, and larval mass during the initial 145h of decomposition. We also measured the pH, temperature, and oxidation-reduction potential of larval masses in situ. Bacteria were cultured aerobically on Standard Nutrient Agar at 22°C and identified using protein or genetic signals. Carcass decomposition followed a typical sigmoidal pattern and associated bacterial communities differed by sampling location and time since death, although all communities were dominated by phyla Actinobacteria, Firmicutes, and Proteobacteria. Larval masses were reducing environments (~-200mV) of neutral pH (6.5-7.5) and high temperature (35°C-40°C). We recommend that culturable postmortem and larval mass microbiology and chemistry be investigated in more detail, as it has potential to complement culture-independent studies and serve as a rapid estimate of PMI.
死后微生物作为物证的潜力日益受到认可。然而，我们对死后微生物的生态学，尤其是与皮肤和幼虫团相关的微生物生态学仍然知之甚少。2013年6月，我们在美国夏威夷瓦胡岛进行了一项实验，以表征正在分解的家猪（Sus scrofa domesticus）尸体的微生物学和化学特性。在分解的最初145小时内，从头部、四肢和幼虫团采集细菌。我们还原位测量了幼虫团的pH值、温度和氧化还原电位。细菌在22°C的标准营养琼脂上进行需氧培养，并使用蛋白质或遗传信号进行鉴定。尸体分解遵循典型的S形模式，相关细菌群落因采样位置和死亡时间而异，尽管所有群落均以放线菌门、厚壁菌门和变形菌门为主。幼虫团是pH值中性（6.5 - 7.5）、高温（35°C - 40°C）的还原环境（约-200mV）。我们建议更详细地研究可培养的死后和幼虫团微生物学及化学，因为它有可能补充非培养依赖性研究，并作为死后间隔时间的快速估计方法。
