Microbial Source Tracking ServicesMore than 30 years after the Clean Water Act, approximately 13% of U.S. surface waters do not meet water quality standards due to the presence of fecal indicator bacteria (e.g. fecal coliforms, E. coli). Furthermore, beach closures and advisories exceeded 20,000 days in each of the past 4 years with more than 60% caused by fecal pollution. The problem continues due to the inability of traditional methods to identify fecal contamination sources so that control measures can be promptly implemented. In a typical watershed, contamination of surface waters can stem from a myriad of potential point and non-point sources containing fecal material from: • humans (sewer leaks, sanitary sewer overflows, septic system failures, stormwater), • dogs and other domestic animals (stormwater, urban runoff), • livestock (confined animal feeding operations), and • wildlife Traditionally, water quality has been assessed by cultivation-based enumeration of fecal indicator bacteria such as fecal coliforms and E. coli. Monitoring fecal indicator bacteria can identify impaired waterbodies and aid in protecting human health. However, traditional approaches have no real diagnostic power to identify the source of fecal pollution and direct corrective actions to improve water quality. Recognition of the limitations of traditional culture-dependent methods and indicator organisms has spawned an entire field of study termed microbial source tracking (MST) which employs cultivation-independent methods to not only assess water quality more accurately but also to identify the source of fecal contamination. Microbial Insights (MI) has developed and licensed quantitative polymerase chain reaction (qPCR) assays for microbial source tracking of fecal contamination of surface waters. PCR is a molecular method in which a specific gene can be amplified permitting detection and quantification of a target DNA marker in a mixture of non-target DNA sequences. Since the target DNA can be extracted directly from environmental samples, cultivation of the indicator organism is not required thus eliminating culture bias while providing rapid detection with greater sensitivity and throughput. Molecular Biological ToolsCurrently, MI is offering MST CENSUS assays for quantifying the following indicators of fecal contamination.
CENSUS - Based on quantitative polymerase chain reaction (qPCR), CENSUS is a nucleic acid based approach to quantify host specific genetic markers to identify sources of fecal contamination. |
