Study On The Application Of The Rapid Detection Of Pathogen In The Surface Water By PCR

In order to establish a method for rapid detection of pathogenic bacteria in surface water by polymerase chain reaction (PCR) technique, this study tried to introduce universal primers with Shigella dysenteriae, Vibrio cholerae, Salmonella typhrmurium, and Escherichia coli as the reference strains. The universal primers were designed and synthesized according to the high conversation of 16S rRNA gene. The DNA of bacteria from several water bodies and secondary effluent in the urban area of Xi'an City were extracted and then amplified with the universal primers, and sequencing and homology analyses of the PCR production were conducted. As a result, the PCR products of the 4 reference strains were identified at 320 bp on the electrophoregrams, and they were further verified by sequencing and homology analyses. The detection limit of the total DNA of E.coli reference strain was about 250ng/L and the sensibility of PCR detection was up to 27.5cfu/100mL. Regarding different water samples, limpid electrophoresis strips were identified at 320 bp for 1 river and 3 lakes in the urban area, as well as the secondary effluent from a domestic wastewater treatment plant, all of which are believed to be under the influence of domestic pollution, while no strip was identified for another river water which is the well protected source for potable water supply.Bacteria enumeration was also conducted by conventional culture method for comparison. Regarding fecael coliform, it was only detected from the secondary effluent and a polluted lake but not the other surface water samples from which pathogenic bacteria were detected by PCR with the universal primers. The PCR method established by this study has manifest advantages over conventional culture method in its rapidness and sensibility for the detection of pathogenic bacteria from surface water. It provides a more reliable approach for the assessment of bacteriological risk of water environmentThe PCR method established by this study has manifest advantages over conventional culture method in its rapidness and sensibility for the detection of pathogenic bacteria from surface water. It provides a more reliable approach for the assessment of bacteriological risk of water environment.