Division of Microbiology and Infectious Diseases (DMID)

Genomic Sequencing and the Amerithrax Investigation

This scanning electron micrograph depicts Bacillus anthracis spores. Credit: Centers for Disease Control and Prevention

DMID supports a range of genomics resources aimed at improving the understanding of pathogens and how they cause disease, and developing potential new targets and platforms for novel drugs, vaccines, and diagnostics. One such resource is the Genomic Sequencing Centers for Infectious Diseases program, which provides human and microbial genotyping as well as rapid and cost-efficient production of high-quality genome sequences of human pathogens and related organisms and invertebrate vectors of infectious diseases.

In addition to providing the scientific community with critical data and tools to analyze and apply findings, the Centers are available to provide unique assistance during public health emergencies. For example, the Federal Bureau of Investigation (FBI) utilized one of the NIAID-funded Centers—The Institute for Genomics Research (TIGR)—in their investigation into the 2001 anthrax letter attacks, also known as the Amerithrax investigation.

NIAID Genomic Sequencing Essential for Identifying Source of Anthrax Spores

During the Amerithrax investigation, the TIGR used whole genome sequencing and comparative genomic analysis to sequence and analyze more than 10 Bacillus anthracis isolates.

NIAID supported sequencing of two B. anthracis genomes that were instrumental in the FBI Amerithrax case. The sequences of these two strains were used as reference points for comparison with the genomes sequenced from Amerithrax isolates. This led to the identification of four distinct genetic mutations unique to B. anthracis isolates from the 2001 anthrax letters. These mutations were used as genetic markers for assays developed by the FBI in Amerithrax investigation and helped the FBI determine that the bacterial spores used in multiple letters containing anthrax came from a common source. This source was later identified by the FBI as a colony located at Ft. Detrick in Maryland.

Impact on Future Research and Investigations

For the first time, these studies clearly demonstrated the advantages of whole genome sequencing and comparative genomics over traditional genotyping methods. This novel strategy has revolutionized how scientists study genetic variation in microbes and has evolved into a critical research, clinical, and forensic tool.

NIAID efforts have also greatly expanded available data by supporting sequencing of additional strains of B. anthracis. The data are currently available to the scientific community through GenBank at the National Center for Biotechnology Information.