Microplate Assay Development for Detecting Microbial Contaminants
Project Title: Assay and Sensor Development to Identify, Detect, and Quantify Microbial Contaminants
Research Locations: Rookery Bay, Naples FL
Last Update: 10-28-03
Decisions to close shellfish beds and beaches due to microbial contaminants in coastal waters have economic repercussions that can be felt on local, regional, and national levels. In order to make these important determinations, managers need accurate, quick, and cost-effective methods for pinpointing the types and levels of contaminants. Traditional culture-based microbial methods are slow, labor intensive, and do not differentiate between human and animal sources of waste. This project is developing a microplate assay that quickly and accurately identifies species of toxic plankton and fecal-indicating bacteria.
Methods: The Microplate Assay
Researchers tested two groups of organisms: toxic dinoflagellates that
cause red tide, and bacteria that indicate the presence of sewage. They
first identified the molecular sequences needed to detect the problem
organisms. From there, they created "molecular probes" which they attached
to the wells of microplates. DNA from a sample was then placed in the
well. If there was a match, a chemical reaction caused a yellow color
to indicate the presence of that organism in the water sample.
- The red tide assay successfully detected Karenia brevisin water samples collected from the Rookery Bay NERR. The assay was sensitive enough to detect "very low" and "present" amounts of this toxic dinoflagellate.
- The sewage-indicating assay utilized a variety of probes. Probes were developed
to detect Escherichia coli, total coliforms, the Bacteroides
fragilis group (anaerobic bacteria found in humans and animals),
and Bacteroides distasonis (associated with the human gut). The
Bacteroides assays are a promising way to distinguish between human and
nonhuman sewage contamination in coastal waters. to be carried out simultaneously,
each one being completed in less than a minute.
Convenient, rapid relay of information
Pre-existing methods require up to 3 days for analysis and relay of information to resource managers. The microplate assay can give managers information in a matter of 2-3 hours. Using this method would make the process quicker, less expensive, and more informative. It would allow for easy storage of samples and
would aid in differentiating between human and non-human fecal pollution sources.
In the Future: An even faster technique
Results of this project have been so successful researchers are now developing a new and even faster technique for identifying microbial contaminants which would allow for hundreds of tests to be carried out simultaneously, each one being completed in less than a minute.
Dr. Jack Fell (305) 361-4603
University of Miami
Dr. Kelly Goodwin (305) 361-4384
National Atlantic Oceanic and
Start -End Date:
01/09/2002 - 01/09/2004
Rookery Bay, Naples FL
For more information:
Dolores Jalbert Leonard
Phone: (603) 862-3685