Effect of a genetically engineered bacteriophage on Enterococcus faecalis biofilms.

•An exogenous inducible promoter controls the phage lytic cycle functions.•Biofilms of both E. faecalis strains were disrupted by infection with bacteriophage.•Confocal Microscopic analysis showed reduction of biomass in phage-treated biofilms.•Dead cells could be seen throughout the depth of the phage-treated biofilm layers.•A 10-100-fold decrease in viable cells was observed after bacteriophage treatment.