Prokaryotic Expression Of Several Virulence Genes And Research Of Partial Characteristics On Porcine Enterococcus Faecalis

Investigations into several virulence genes were conducted at the same time through molecular epidemiology in order to acquaint us with expression and related characteristics of several virulence genes isolates of the clinical Enterococcus faecalis,and to provide references for the pathogenesis of Enterococcus and its treatment and control measure.In order to investigate the virulence situation of the gelatinase E gene in clinically separated Enterococcus faecalis and the mechanism of gelatin liquification reaction,two Enterococcus faecalis isolated from the anal swabs of swine pheasant diarrhea infected pigs were selected,one of them was able to liquify gelatine,and vitro recombinant of 6 virulence genes(esp,gelE,sprE,fsrA,fsrB,fsrC)in it was successfully carried out,meanwhile the induced expression of 3 recombinant plasmids(pet28a-esp,pet28a-gelE,pet28a-fsrB)also succeeded.Only prokaryotic expression was carried out for the other strain which was not able to liquify gelatin,to be compared and analyzed as control group.The gelatin liquification experiments on the purified protein and protein mixture were carried out,and the results showed that liquification could not occur.In this study,5 kinds of virulence gene(gelE,fsrA,fsrB,fsrC,sprE)in 375 strains of Enterococcus were tested through PCR method,virulence genes were detected in 263 strains,with its detection ratio 41.1%,45.9%,50.1%,48%,46.7% respectively,result showed that Enterococcus faecalis possess the highest rate of detection among Enterococcus.The two virulence genes with the highest detection rate in fecal enterococci were fsrB and gelE,with the detection ratio of 73.5% and 72.9%,and the rates for sprE,fsrA and fsrC were 71.2%,68.2% and 69.4%.This turns out that Enterococcus faecalis is the main pathogen among Enterococci and the conditioned pathogen which is most likely to cause ailment in the animal body.Among the combinations of virulence genes in Enterococcus,there were 110 strains with all five virulence genes,106 of them were Enterococcus faecalis,the rest 4 strains were other enterococci.This indicates that Enterococcus faecalis is the main virulence gene carrier among Enterococcus with the highest rate of carring several virulence genes at the same time.Gelatin liquification experiments were performed on 375 strains of Enterococcus,result shows that gelE was detected among 154 of them,106 strains of them were able to liquify gelatin and all of the 106 were Enterococcus faecalis.Meanwhile,106 of 110 strains with all 5 virulence genes were Enterococcus faecalis,all of them were capable of liquifying gelatin while 4 others were not able to do that.This indicates that the phenotype of liquefying gelatin is more likely to occur in Enterococcus faecalis and there is certain correlation between the 5 kinds of virulence genes.