Microbiological water quality monitoring is a challenging issue as no standard method covers both quantification and identification of the source of pollution. Current culture based microbiological water quality measurement techniques predominantly focus on traditional indicator bacteria Escherichia coli and Enterococcus spp. The culture based methods have limitations starting from sampling to data processing so alternative indicators and culture independent methodologies are being developed to overcome this problem.
MST is the attempt to match a microbe (e.g. bacterium) from a polluted site (e.g. water body) and a known source to suggest the origin of fecal pollution. This can be achieved using a variety of target organisms in either library-dependent or library-independent approaches.
The polymerase chain reaction-based MST methods can be extended to other target organisms by adapting the assays as necessary. In turn these protocols can be adapted based on the characteristics of the geographical location of interest e.g. areas dominated by specific breeds of livestock or wildlife. The evolving field of MST requires that the laboratory is able to evaluate and apply new source tracking protocols as they become available, and improve our expertise in the application of new methods.
Microbial source tracking (MST) is a developing field that has produced new methods to differentiate various sources of fecal contamination. However, there is a need for a consensus approach and standardization of methodologies to act as a yardstick whereby comparative studies can be undertaken for all water resources, including freshwater, marine and ground water.