Abstract:In this study, we used E. faecalis (efaA+, efaA-) to study the role of enterococcus endocarditis antigen EfaA on biofilm formation.The ability of biofilm formation were detected by microtiter plate assay. E. faecalis strains S14, S14-pAT28 and S14-pAT28-efaA were cultivated in 96-well for 24 hours; biofilms were detected by microtiter plate reader after Gram crystal violet staining. Optical density at 570 nm for each strain were determined and compared. MTT method was used to compare the bioactivity of biofilms of efaA+,efaA- strains by testing the OD492, which indicated the vital bacteria counts of biofilm. The mean thickness and the maximal thickness of biofilms of efaA+,efaA- E. faecalis strains were compared by CLSM. It was shown that the biofilm formation ability (OD570 values) of transformant S14-pAT28-efaA detected by microtiter plate assay, the vital bacteria counts (OD492values) of S14-pAT28-efaA tested by MTT method, the mean thickness and the maximal thickness of biofilms of S14-pAT28-efaA observed by CLSM were all greater than that of wild strain (S14) and control strain (S14-pAT28) respectively (P<0.05). There was no significant difference between control strain S14-pAT28 and wild strain S14 (P>0.05). It was concluded that E. faecalis EfaA might be in favor of the biofilm formation of E. faecalis.
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