Characterization of φEf-vB1 prophage infecting oral Enterococcus faecalis and enhancing bacterial biofilm formation

Abstract

Introduction.Enterococcus faecalisis a facultative, anaerobic, opportunistic pathogen associated with medical and dental diseases. Bacterial phenotypic traits and pathogenesis are often influenced by lysogeny.Aim.The aim of this study was to characterize both the morphology and complete genome sequences of induced prophages purified fromE. faecalisclinical isolates.Methodology.E. faecalisisolates were recovered from the roots of teeth of patients attending an endodontic clinic. The morphological features of isolated phage were characterized using transmission electron microscopy (TEM). DNA sequencing was performed using the Illumina MiSeq platform.Results.TEM indicated that the isolated φEf-vB1 prophage belongs to the familySiphoviridae. The φEf-vB1 prophage was stable over a wide range of temperatures and pH. Sequencing of φEf-vB1 DNA revealed that the phage genome is 37 561 bp in length with a G+C content of 37.6mol% and contained 53 ORFs. Comparison with previously predicted prophage genomes usingblastrevealed that φEf-vB1 has a high sequence similarity to previously characterized phage genomes. The lysogenicE. faecalisstrain exhibited a higher biofilm formation capacity relative to the non-lysogenic strain.Conclusion.The current findings highlight the role of lysogeny in modification ofE. faecalisproperties and reveal the potential importance of prophages inE. faecalisbiology and pathogenesis.