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The Enterococcus QPCR Method for Recreational Water Quality Testing: Testing Background, Performance and Issues
Citation:
HAUGLAND, R. A. The Enterococcus QPCR Method for Recreational Water Quality Testing: Testing Background, Performance and Issues. Presented at 7th Annual Great Lakes Beach Association Meeting, Traverse City, MI, October 03 - 05, 2007.
Impact/Purpose:
1. Determine effects of storage by freezing of NEEAR study samples on QPCR measurements of enterococci. 2. Identify, from an expanded pool of candidates, the general fecal indicator microorganism(s) (i.e. different taxonomic or phylogenetically-related groups from all animal sources) whose densities in NEEAR study water samples, as measured by QPCR analysis, best correlate with illness rates monitored in the NEEAR study. 3. Determine whether illnesses rates in the NEEAR studies are better correlated with QPCR measurements of fecal indicator organisms from human as opposed to general sources (subject to the availability or development of suitable QPCR assays for human fecal indicators).
Description:
Currently accepted culture-based monitoring methods for fecal indicator bacteria in surface waters take at least 24 hr to determine if unacceptable levels of fecal pollution have reached our recreational beaches. During this waiting period changing water conditions may result either in unnecessary beach closings or exposures to unsafe conditions. Newer molecular based technologies such as real-time quantitative PCR (QPCR) have the ability to provide measurements of fecal indicator bacteria nucleic acids within a few hours and thus could lead to more accurate and health protective advisories to the public due to their greater timeliness. The National Epidemiological and Environmental Assessment of Recreational (NEEAR) Waters Studies, performed by U.S. EPA and CDC in 2003-2005 demonstrated a correlation between swimming-related gastrointestinal illness rates and QPCR measurements of Enterococcus fecal bacteria at Great Lakes fresh water and Gulf Coast marine water beaches. These results suggest that the QPCR method can provide determinations of fecal pollution levels that are predictive of swimming-related health risks. This presentation will provide an overview of the Enterococcus QPCR method including a brief description of the method and its history, a synopsis of studies that have been conducted to determine its performance characteristics and a discussion of unresolved issues associated with its potential implementation on a national scale.