Phage mediated detection of Bacillus anthracis on deliberately contaminated fresh foods

The nations food supply is particularly vulnerable to a bioterrorist attack. Bacillus anthracis, the causative agent of anthrax, is a Category A pathogen that is considered a high priority biological weapon. Gastrointestinal anthrax is caused by the ingestion of B. anthracis contaminated foods or liquids. B. anthracis spores, which are the infectious form of the disease, are extremely resistant to chemical and physical treatment. Thus, minimally processed foods or liquids such as milk are the primary areas of concern because they do not receive the protective benefit of cooking. The risk is compounded because gastrointestinal anthrax is very difficult to diagnose since the disease has general symptoms such as nausea, vomiting, and diarrhea; if appropriate treatment is not administered within the first 24 h after exposure, the disease can develop into a systemic form that is rapidly fatal with mortality rates exceeding 40%. Consequently, novel surveillance methodologies that can detect B. anthracis on adulterated liquids and foods are critical for enhancing food safety. The long-term goal of our research is to develop a simple and rapid B. anthracis detection kit that can be used to identify this priority pathogen on deliberately contaminated foods or liquids. Our Phase I research obtained the proof of principle results by generating a genetically engineered reporter phage that could detect B. anthracis. The reporter phage was constructed by integrating the "light" genes into the genome of a B. anthracis phage. The resulting "light-tagged" reporter phage was able to rapidly (within minutes) confer a bioluminescent (light) signal to B. anthracis. The Phase II research will build upon the Phase I research by: 1: Demonstrating that the reporter phage can detect many different forms of B. anthracis. 2: Demonstrating that the reporter phage detects B. anthracis only, and not other non-pathogenic bacteria in order to reduce the possibility of false alarms. 3: Demonstrating that the reporter phage can detect B. anthracis on contaminated liquids and foods. The research proposed in this application is significant because it will potentially save lives by providing the surveillance methodology for the identification of B. anthracis on deliberately contaminated liquids and foods. The research will enhance food safety, but will also be directly beneficial to the Federal Government for the detection of anthrax-contaminated buildings and offices, and also to the clinical community as a diagnostic tool for the detection of B. anthracis.