The Application of a Universal Assay for Identifying the Source of Fecal Contamination in Southeast Michigan Water Bodies

Abstract Recreational water quality monitoring (RWQM) is an important tool to aid public health officials in preventing exposure to waterborne pathogens originating from fecal contamination. RWQM methods rely on fecal indicator bacteria (FIB) such as E. coli or enterococci. Unfortunately, E. coli and other FIB are not strict anaerobes and can naturalize and reproduce in the environment. These naturalized populations can be resuspended due to wave action or other disturbances, sometimes giving a false positive for fecal contamination using RWQM methods. This project implemented a universal marker or a non-host specific MST target to determine whether it could differentiate between recent fecal contamination and resuspended populations of bacteria. Five public beaches in southeast Michigan were monitored for FIB and MST. The non-host specific marker in addition to the FIB was successfully applied to determine whether elevated E. coli levels were caused by recent fecal contamination or resuspension.