"This is an extremely important breakthrough in phage-based detection..."

A method for capture and detection of Escherichia coli O157:H7 using polymer-immobilized phage

Investigators: Mark Morgan (Department of Food Science), Bruce Applegate (Department of Food Science)

Project Report 2007 - 2008

» Download Project Report 2007 - 2008

Project Rationale

Foodborne illnesses in developed nations affect up to 30 percent of the population annually with microbially-associated illnesses cost an estimated $7 to $33 billion dollars annually. More serious is the mortality rate of foodborne and waterborne infectious diseases in developing countries, amounting to an estimated 2.1 million deaths annually (mostly infants and children). Despite the increasing incidence of foodborne illnesses and contamination, there are currently few if any early-detection methodologies which are robust, user-friendly, and applicable to widespread use in developing nations. The phage-based technology under development in this project would circumvent many of the limitations associated with existing technologies by providing a small, inexpensive, field-deployable diagnostic platform for detecting minute amounts of bacteria in food and, potentially, in clinical diagnostics. The platform is based on the immobilization of a genetically modified bacteriophage specific for Escherichia coli O157:H7, which traps and infects the E. coli O157:H7, resulting in the production of a visible red compound which enables visual detection of the pathogen.

Project Objectives

  • Demonstrate that ultraviolet polymerization is an effective technique to attach phages to polymer surfaces.
  • Optimize the the efficiency of the polymerization process.
  • Modify the phage phiV10 to include luxCDABE and cobA reporters.

Project Highlights

During fiscal year 2007, we developed technology supporting the production of E. coli O157:H7-specific bacteriophage phiV 10 in a nonpathogenic E. coli host. The phage was simply integrated into the genome of a lab strain of E. coli to form a lysogen, which could subsequently be released in the programmed expression of recA. This is an extremely important breakthrough in phage-based detection in terms of commercialization. Currently, to produce large quantities of phage, it must be grown in a specific host, which in this case is E. coli O157:H7. This is problematic for two reasons: first, growing 500 liters of E. coli O157:H7 poses a significant risk and would require substantially greater monitoring than existing bacterial-based biotech protocols. Second, if a single E. coli O157:H7 used in production was found in the commercialized assay, it would be catastrophic to the commercialization.

Annual Report