| This paper makes a systematic study on microbiology contamination of Pseudomonasaeruginosa, Enterococcus faecalis and spore-forming sulphite-reducing anaerobes inGuangdong mineral and spring water plants. Then we focused on the relevant hazards of P.aeruginosa and E. faecalis isolated from the water, and constructed the fingerprint bygenotyping, with an attempt to find out about its correlation, which surely serves as areference in drinking water safety evaluation, microbiology contamination control anddrinking water safety improvement.The main research findings are as follows:(1) The contamination rate of P. aeruginosa in Guangdong mineral water plants andspring water plants is20.9%, with the contamination rates of source water, carbon water andfinished water are respectively25.0%,32.3%and4.6%. The contamination rate of E. faecalisis17.0%, with source water, carbon water and finished water taking up26.3%,20.0%and3.1%respectively. The contamination rate of spore-forming sulphite-reducing anaerobes is24.76%, with source water, carbon water and finished water taking up39.5%,30.8%and1.5%respectively.It is worth mentioning that there is a big difference in contamination situation betweenthose two kinds of plants, no matter it is concerned with source water, carbon water orfinished water, with spring water having more contamination than mineral water. As forsource water in spring water, groundwater has less microbiology than surface water.(2) According to the virulence genes test on43P. aeruginosa, toxA, phzM, lasB, exoUand exoS were respectively diagnosed with the percentage of93.0%(40/43),100%(43/43),100%(43/43),20.9%(9/43) and79.1%(34/43), and isolates virulence genes were widelyspread, and with stronger pathogenicity. What‘s more, results of drug sensitivity test suggestno existence of drug-resistant strain, which indicate that though those bacterial strains isolatedfrom water plants in Guangdong province have strong virulence, they are easy to control. Inthe meanwhile, the researcher makes use of ERIC-PCR and RAPD to conduct a sourceanalysis on P. aeruginosa, and it is revealed that these two methods both have great discrimination with the discovery of the variety of bacteria strains but no major genotype.(1) According to the research on35E. faecalis isolated from water, the seven virulencegenes, namely ace, efaA, gelE, asa1, esp, cylA, hyl, were diagnosed respectively with apercentage of80.0%(28/35),100%(35/35),97.1%(34/35),42.8%(15/35),8.6%(3/35),5.7%(2/35) and0(0/35). The results indicate that the virulence genes were relatively few fromthe isolates, suggesting those strains are relevantly safe, and not so virulent. Furthermore,ERIC-PCR molecular subtyping has been carried out on E. faecalis, dividing the35E.faecalis into three groups and17types, with B group taking the majority.This research is the first attempt on successfully acquiring relevant pathogencontamination data about Guangdong mineral water and spring water and also formedsubtyping methods and accomplished molecular subtyping, which lays a solid groundwork forfurther research on drinking water microbiology. At the same time, it will help to make theprecaution and control over pathogen contamination in drinking water all the more to thepoint, and much more effective. |
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