Viability Assay for Monitoring Decontamination of Pathogenic Bacteria

Period of Performance: 08/01/2002 - 01/31/2003


Phase 1 STTR

Recipient Firm

Luna Innovations, Inc.
301 1st St Suite 200
Roanoke, VA 24011
Principal Investigator
Firm POC

Research Institution

Virginia Polytechnic Institute
Sponsored Programs 0170
Blacksburg, VA 24061
Institution POC


To determine the effectiveness of antimicrobial agents in decontamination and antimicrobial efficacy testing, the plate count method has been traditionally used. This method requires trained technical expertise, large amounts of microbiological growth media and up to several days to complete and often with unreliable results. Luna Innovations proposes to develop a rapid, automated means of determining the efficacy of antimicrobial agents on vegetative bacterial cells using fluorescent probes and antibiotics targeting the primary susceptibility regions of tester organisms (e.g., cell wall, cell membrane and cellular respiration). In the Phase I work, the fluorescence-based formats will focus on measuring changes in pH, redox and cell metabolism to quantify the amount of viable organisms remaining after treatment with the decontaminants and determine the kinetics associated with the cell destruction. Fluorescence-based responses obtained in 5-10 minutes will be compared to traditional plate count determinations as controls. Tester strains will include ampicillin+/- and b-galactosidase+/- strains of Escherichia coli and protein A+/- strains of Staphyloccus aereus. In subsequent Phase II studies, the types of tester organisms will be expanded to include other pathogenic microorganisms and indicator compounds. In addition, the instrumentation will be adapted to have multiple sampling and the high throughput capabilities. The introduction of the concept of viable but nonculturable cells in the 1980s has led to important research work concerning the existence and significance of these kinds of cells within bacterial communities. In addition, quantification of total bacterial numbers in a fast and reliable fashion is a basic and essential task in several areas of microbiology, including public health, biotechnology, food and water industries, pharmaceuticals and the natural environment. Our proposed technology would greatly increase the speed and reliability with which organisms could be assessed after a decontamination event both in the laboratory and in the environment.