Authors
Shefali Anand, Dr. Kunal Kishor, Farha Azmeen
Abstract
Microbial Forensics is a promising branch of Forensic Science that fills the knowledge gaps and empowers the conventional and traditional forensic investigative procedures. Microbial fingerprinting can assist in the field of forensics in the areas like source tracking, geolocation, circumstances of death and trace evidences. The studies performed for the forensic investigations mostly focus on the internal organ samples and the soil samples, whereas the microbiome present in mouth, skin and vaginal samples are routinely collected in the cases like femicide and sexual assault. Microorganisms are ubiquitous in nature and hence, are involved in the natural metabolic activities, and therefore they are considered as physical evidence in the forensic investigations. The microbial species attacks the cadaver after the death of an organism and starts the decomposition of the body. The whole process of decomposition is an amalgamation of microbial and entomological attack which is dependent on various factors like soil, surrounding environment, temperature, humidity etc. The study of the microbial species can be an important aspect of the forensic investigations as it helps in the estimation of Post Mortem Interval (PMI). From the last few years, microbial forensics is gaining limelight as microbes can prove to be better evidence than entomological species for estimating Post Mortem Interval. Keywords: Microbial Forensics, Post Mortem Interval, Microorganisms, Fingerprinting
Introduction
The field of science is a collaboration of multiple disciplines like physics, chemistry, geology, biology, and many more. The application of these basic sciences in the field of law is what we call as “Forensic Science”. Forensic science itself consist of fields like examination of Questioned Documents, Cyber Forensic, Toxicology, Forensic Physics, Forensic Chemistry, Forensic Biology and Serology etc which are based on the application of general laws of sciences and hence helps in the courtroom for solving different types of criminal and civil cases. One of these fields of forensic science is “Microbial Forensics”. This field is concerned with the viruses, bacteria, algae, and other microbes which are present in and around us, living or dead. The focus is on the type of microbes they are, their structure, classification, function, life span, life cycle, presence and are the microbes good or not so good for the humans. All these aspects related to microbes were studied and applied in the field of forensic science where the information that is obtained is very crucial for solving the case. The information like time of death, place, origin, body type, etc can be extracted (Janaway et al., 2009).
The microbes play an important role in the decomposition process as they recycle the organic matter present in the living bodies and the nutrients which we extract from the food we consume, and hence the food webs are formed in the environment. Also, 99% of nutrients and organic matter is cycled by microbes from plants organic matter and nutrients (Carter et al., 2008).
The presence of microbes during the process of decomposition provides the major chunk of the information about the cadaver. As decomposition is a process in which multiple factors like temperature, climate, humidity, the condition of cadaver, insects etc. The decompositions process acts as an intimate association of these factors which in turn act an important factor for the ecological setup. Studying these physiologic and metabolic changes that occurs in the cadaver due to the microbial action provides the information about the manner of death, time since death, location of death etc. and these microbes which are associated with the cadaver are termed as “Thanatomicrobiome” (Vass, 2001).
References
Amendt, Jens, et al. “Best Practice in Forensic Entomology—standards and Guidelines.” International Journal of Legal Medicine, vol. 121, no. 2, Springer Science+Business Media, Mar. 2007, pp. 90–104. https://doi.org/10.1007/s00414-006-0086-x.
Amendt, Jens, et al. “Forensic Entomology.” Naturwissenschaften, vol. 91, no. 2, Springer Science+Business Media, Feb. 2004, pp. 51–65. https://doi.org/10.1007/s00114-003-0493-5.
Belk, Aeriel D., et al. “Microbiome Data Accurately Predicts the Postmortem Interval Using Random Forest Regression Models.” Genes, vol. 9, no. 2, MDPI, Feb. 2018, p. 104. https://doi.org/10.3390/genes9020104.
Carter, David, et al. “Temperature Affects Microbial Decomposition of Cadavers (Rattus Rattus) in Contrasting Soils.” Applied Soil Ecology, vol. 40, no. 1, Elsevier BV, Sept. 2008, pp. 129–37. https://doi.org/10.1016/j.apsoil.2008.03.010.
Chen, Yanfei, et al. “Characterization of Fecal Microbial Communities in Patients With Liver Cirrhosis.” Hepatology, vol. 54, no. 2, Wiley, Aug. 2011, pp. 562–72. https://doi.org/10.1002/hep.24423.
Damann, Franklin E., et al. “Potential Use of Bacterial Community Succession in Decaying Human Bone for Estimating Postmortem Interval,,.” Journal of Forensic Sciences, vol. 60, no. 4, Wiley-Blackwell, July 2015, pp. 844–50. https://doi.org/10.1111/1556-4029.12744.
Durbán, Ana, et al. “Assessing Gut Microbial Diversity From Feces and Rectal Mucosa.” Microbial Ecology, vol. 61, no. 1, Springer Science+Business Media, Jan. 2011, pp. 123–33. https://doi.org/10.1007/s00248-010-9738-y.
Hewadikaram, Kamani, and Michael Goff. “Effect of Carcass Size on Rate of Decomposition and Arthropod Succession Patterns.” American Journal of Forensic Medicine and Pathology, vol. 12, no. 3, Lippincott Williams and Wilkins, Sept. 1991, pp. 235–40. https://doi.org/10.1097/00000433-199109000-00013.
Howard, Gary T., et al. “Characterization of the Soil Microbial Community Associated With the Decomposition of a Swine Carcass.” International Biodeterioration & Biodegradation, vol. 64, no. 4, Elsevier BV, July 2010, pp. 300–04. https://doi.org/10.1016/j.ibiod.2010.02.006.
Janaway, Robert C., et al. “Decomposition of Human Remains.” Humana Press eBooks, Humana Press, 2009, pp. 313–34. https://doi.org/10.1007/978-1-59745-327-1_14.
Johnson, Hunter J., et al. “A Machine Learning Approach for Using the Postmortem Skin Microbiome to Estimate the Postmortem Interval.” PLOS ONE, vol. 11, no. 12, Public Library of Science, Dec. 2016, p. e0167370. https://doi.org/10.1371/journal.pone.0167370.
Lauber, Christian L., et al. “Vertebrate Decomposition Is Accelerated by Soil Microbes.” Applied and Environmental Microbiology, vol. 80, no. 16, American Society for Microbiology, Aug. 2014, pp. 4920–29. https://doi.org/10.1128/aem.00957-14.
Lax, Simon, et al. “Forensic Analysis of the Microbiome of Phones and Shoes.” Microbiome, vol. 3, no. 1, BioMed Central, May 2015, https://doi.org/10.1186/s40168-015-0082-9.
Metcalf, Jessica L., et al. “A Microbial Clock Provides an Accurate Estimate of the Postmortem Interval in a Mouse Model System.” eLife, vol. 2, eLife Sciences Publications Ltd, Oct. 2013, https://doi.org/10.7554/elife.01104.
Metcalf, Jessica L., et al. “Microbial Community Assembly and Metabolic Function During Mammalian Corpse Decomposition.” Science, vol. 351, no. 6269, American Association for the Advancement of Science, Jan. 2016, pp. 158–62. https://doi.org/10.1126/science.aad2646.
Parkinson, Rachel H., et al. “Microbial Community Analysis of Human Decomposition on Soil.” Springer eBooks, Springer Nature, 2009, pp. 379–94. https://doi.org/10.1007/978-1-4020-9204-6_24.
Pechal, Jennifer L., et al. “A Large-scale Survey of the Postmortem Human Microbiome, and Its Potential to Provide Insight Into the Living Health Condition.” Scientific Reports, vol. 8, no. 1, Nature Portfolio, Apr. 2018, https://doi.org/10.1038/s41598-018-23989-w.
Vass, Arpad A. "Beyond the grave-understanding human decomposition." Microbiology today 28 (2001): 190-193.
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