Microbial Source Tracking

This chapter focuses on microbial source tracking (MST) techniques and methodologies, which can be used to discriminate between human and nonhuman sources of fecal contamination. Descriptions are given of library-dependent methods, which require the development of a "library of bacterial strains from known fecal sources which can be used for comparison with unknown isolates." Library-independent techniques are also discussed, which rely on the detection of specific host-associated genetic markers within an isolate or sample. Subsequently, MST methods utilizing bacteria within the genus Bacteroides are documented. Finally, applications of MST to evaluate environmental water quality are described, as well as the use of MST to identify pollution sources in impaired watersheds.