Research On The Escherichia Coli Diversity And Microbial Source Tracking Of The Offshore

Dalian Jinzhou Bay--a place integrating livestock breeding, aquaculture, tourism, habitation and so on, located along the coast of Bohai, is one of the main Bays in Dalian. The level of colon bacterial colony in the waters close to the coast exceeds theⅢclass water quality standards due to serious pollution from excrement. In recently years, MST(Microbial Source Tracking) technology has emerged after Europe and other developed countries carrying out a study on the use of microbes to trace the origin of water feces pollution. The technology not only can correctly identify pollution sources, but also can assess the degree of contribution of single pollution sources. It provides a scientific basis for risk assessments of water feces pollution, distribution of daily maximum load, drawing up the best management plans, etc.Investigation into the diversity of Escherichia coli in the waters of Dalian Jinzhou Bay was conducted, applying REP-PCR method of genotyping techniques. Results point out the diversity of Escherichia coli in the waters of Dalian Jinzhou Bay is comparatively high. Adopting MST library dependent and REP-PCR method of genotyping techniques, while setting the suspicious feces pollution sources as human, chickens, pigs and cattle, the database of suspicious feces pollution sources was established. Based on the database, the feces pollution sources in the waters of Dalian Jinzhou Bay and the contribution rate of single pollution sources could be identified.The bacterium database of Escherichia coli from suspicious fecal pollution sources was established. The total number of Escherichia coli is 369, including 114 from human beings,74 from chickens,90 from pigs and 91 from cattle. REP-PCR fingerprint spectrum database of Escherichia coli from suspicious fecal pollution sources was also built.The total number of electrophoretogram is 35, including 11 from human beings,7 from chickens.Results show the fecal pollution in the waters of Dalian Jinzhou Bay mainly comes from animals. Fecal pollution from cattle accounts for the largest proportion, with pollution from pigs second and pollution from chickens the lightest; fecal pollution from human beings is the highest when assessed from fecal pollution contribution rate of single species.