Student Research: Eyob Mazengia

, Environmental Health Technology (Tech) - No longer offered, 1998
Faculty Advisor:

Microbial Source Tracking: Utility of a Clonal Database


Many pathogens are spread by fecal contamination of water. E. coli has been used as an indicator organism to assess the potential presence of fecal contamination or pathogens. The utility of E. coli as an indicator organism is limited by the lack of appropriate methodologies to track point and non-point sources of microbial pollution. The objectives of this study were to evaluate the use of a clonal database of E. coli for the purpose of Microbial source tracking and to test the feasibility of the MST database to identify sources of fecal pollution in diverse geographical locations.

In this study, 2142 isolates from 32 different sources including humans, domestic, farm and wild animals were processed. These isolates were typed using ribosomal RNA method with two restriction enzymes (ECOR I and PVU II). A total of 873 clones were found of which 823 (94%) were source-specific clones and 32 (4%) transient clones. Out of the 32 transient clones, 19 were shared by humans and animals.

The preliminary data analysis shows that each source type, whether animals or humans, carries a group of unique clones of E. coli. Therefore, the MST database can be used to effectively trace sources of fecal pollution as well as differentiate between fecal pollution from humans and animals. However, because of fewer samples from diverse geographical locations, the MST’s ability to source track remote areas not included in the database was inconclusive.