Killing efficiency and molecular mechanisms of probiotics on vancomycin-resistant Enterococcus faecalis V583

OBJECTIVE To determine the optimal conditions and molecular mechanism of killing V583 by common probiotics（Enterococcus faecium, Bacillus subtilis, Enterococcus faecalis, Bacillus cereus）. METHODS Probiotics that had obvious killing effect on V583 were screened by bacterial co-cultivation technology. The killing efficiency of V583 between within 6 and 24 hours were compared according to the method of multiple dilution. The differences in bacterial genomics between bacteria of different killing efficiencies were compared and the mechanism of V583 killing was explored. RESULTS E. faecalis has the best killing effect on V583; E. faecalis can effectively kill more than 70% of the V583 strains within 6 hours when they were equally prepared. Comparative genomics analysis showed that hemolysin gene and toxin-antitoxin system（TA system） of E. faecalis were closely related to the killing role of the strain. CONCLUSION In this study, the killing effect of various E. faecalis isolated from human body is analyzed and the molecular mechanism of the effect on V583 in the minimum bacteria is found, which plays a certain guiding role in the development of probiotics for the prevention and treatment of V583 in clinic.