Isolation of a lytic bacteriophage vB_EfaS_PHB08 and its endolysin lys08 against Enterococcus faecalis biofilm

Abstract Background: Enterococcus faecalis is an opportunistic pathogen can cause a variety of diseases, such as urinary tract infections and wound infections in human and animals. Recently, bacteriophages and their derivatives represent a good effect on fighting against bacterial infections. Methods: We isolated virulent bacteriophages of E. faecalis using the double-layer plate method. The bio-activities of the phage isolated were determined via one-step growth curve testing and bacterial killing assays. Illumina HiSeq sequencing was performed to determine the genetic characteristics and the lysins of the phage. Protein expression and antibiofilm assays were also performed to highlight the bio-activities of the phage lysins. Results: We isolated a virulent bacteriophage vB_EfaS_PHB08 (thereafter PHB08) from the sewage nearby hospital. PHB08 possessed a linear double-stranded DNA genome with 55,244 bp in length, which encoded 91 putative coding sequences (CDS). We found that PHB08 could inhibit the growth of host bacteria for 12 h. In vegetable models, PHB08 can reduce 1´105 Colony Forming Units (CFU) of E. faecalis per square centimeter at room temperature (25 °C) for 24 h. In addition, PHB08 and its endolysin can remove the biofilm formed by E. faecalis. Conclusions: A virulent phage and endolysin displayed a good effect on reducing and/or eradicating E. faecalis infection and biofilm.