Forensic Microbiology

Extract

Forensic microbiology, like other areas of forensic science, deals with determining the cause of death and the identification of people who have committed crimes. Forensic microbiology is a newer area of forensic science that gained importance after the Bacillus anthracis attacks launched through the United States Postal Service in 2001. Forensic microbiology goes beyond testing performed by clinical microbiology and public health laboratories. This field of study relies upon classic microbiology techniques, such as cultures and biochemical identification, but also incorporates molecular biology assays, genetics, and phylogenetics. In addition, forensic principles, evidence collection, chain of custody, and court presentations are critical.

An important role of forensic microbiology is to determine the “microbial signature” of an agent recovered in a criminal case. In this regard, the agent's similarity to other species or strains is determined in an effort to find the source of the agent. Phenotypic characteristics have been generally unreliable because they change based on environmental conditions. Therefore, the emphasis is placed on genotype variation, such as “DNA fingerprints” and polymorphisms. For example, the genome of an evidentiary sample can be compared to a reference sample to see if they are from the same source or have a recent lineage. Some of the same techniques used in human DNA studies have been applied to microbial analysis: microsatellite and minisatellite loci typing, single nucleotide polymorphism analyses, and real time polymerase chain reaction (PCR). In addition, multilocus variable number tandem repeat analysis, which is analogous to the multiplex short tandem repeat typing…

ABBREVIATIONS: CDC, Centers for Disease Control and Prevention; DNA, deoxyribose nucleic acid; HIV, human immunodeficiency virus; LRN, Laboratory Response Network; PCR, polymerase chain reaction; SIDS, sudden infant death syndrome