| Enteroccoccus is human and animal's intestines constant bacterium. It is an important opportunistic pathogen. By way of microbial additive, enterococcus has been used to stabilize and regulate intestinal bacteria for long time. In recent years, due to the misuse of antibiotics which made enterococcus infections rising and became the main pathogens in the hospital. Hemolysin is one important enterococcal virulence factor, which is able to lyse erythrocytes, kill leucocytes as well as contaminate heart. The cultural condition of enterococcal hemolysin and its biological characteristic are the significant tache for investigating enterococcus pathogentic mechanism.This test analysed 11 clinical isolates of enterococci hemolysis, and compared with 30 healthy sheep isolates, a standard G-Streptococcus (C55950) and a standard enterococcus (F6-1.0130). plate assay (PA), Contact Hemolysis (CH), Supernatant assay (SA), Culture Hemolysis (CLH), and three types of SA improved methods were used to detect the haemolytic characteristics of rabbit blood and sheep blood which were infected by forenamed bacteria. The results showed that the 7 of 11 clinical isolates were hemolysis to rabbit blood in PA and CLH assay, and the remaining four were insoluble; 11 isolates had no hemolysis when in CH, SA and three SA assays. But in sheep blood plate their hemolytic characteristic was weak, only four hadα- hemolysis. C55950-G in all assays had haemolytic characteristic. F6-1.0130 strain had sheepα- hemolysis, had no rabbit hemolysis. The 3 of 11 clinical isolates'heamolytic characteristic was consistent to enterococci standard strains'. 30 healthy sheep isolates'hemolytic characteristic was unstable, 16 strains hadβ- hemolysis at the initial separation. But only two still had hemolytic capacity after many generations. Therefore, different enterococci isolates of sheep have different heamolytic characteristic, and their hemolytic ability are very different when act on the sheep blood and the blood of the rabbit respectively. Enterococcus couldn't dissolve rabbit blood in all three SA methods. So we speculated that the produce of sheep enterococci hemolysis needs red blood cells'inducement, which is a combination of cells.We screened out a relatively hemolytic better isolate of enterococci E129-3. Using CLH methods to detect the effect of different cultural conditions on hemolysin. The results showed that the THB broth vaccinates 2% seed fluid in pH8.5, 40℃settles raises 12-24h, under this condition, could produce hemolysin quite well. Red blood cells from mouse, rabbit, and dog were observed to be sensitive, while those from cattle were less susceptible. This hemolysin could be activated by 1,4-Dithiothreitol (DTT), Ca2+ ,while could be restrained by proteinase K, EDTA, Zn2+, Cu2+.Using optical microscope, electrical microscope to observe E129-3 strain's effect on rabbit erythrocytes, we found that inconsistent coloring occured or electronic cloud density obviously decreased in the cytoplasm after 2 hours, and the number of red blood cells significantly reduced after 5 hours. The SDS-PAGE of E129-3 strain's cultural products indicated that the protein expression profiles are inconsistent between F6-1.0130 and E129-3, moreover, a very low protein expression and a few species of E129-3 presented in the absence of blood inducement, but the condition reversed at the presence of blood. This suggested that there are a great deal of silence genes in enterococcus, which can be induced at the presence of revulsant.
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