title: Bacteriophages induced from lysogenic root canal isolates of Enterococcus faecalis.
abstract: BACKGROUND
  Bacterial viruses play crucial roles in the pathogenesis of many systemic diseases. They are known to inhabit the oral cavity, both as free virions and as prophages in lysogenic bacterial strains; however, there has been no report of bacteriophages in endodontic infections. In this study, we sought to detect, isolate, and describe temperate bacteriophages harbored by Enterococcus faecalis strains isolated from endodontic infections.
  
  
  METHODS
  Ten E. faecalis strains were isolated from root canals of teeth undergoing retreatment following unsuccessful endodontic therapy. Mitomycin C was used to induce any prophages present in the bacterial isolates. The induced phages were purified and examined using electron microscopy. The DNA extracted from one of the phage isolates was subjected to restriction endonuclease digestion and agarose electrophoresis analysis.
  
  
  RESULTS
  Lysogeny was demonstrated in 4 of the 10 E. faecalis strains. Three of the lysogenic strains yielded phages exhibiting a Siphoviridae morphology, with long, non-contractile tails 130 nm in length, and spherical/icosahedral heads 41 nm in diameter. The virus induced from the fourth lysogenic E. faecalis strain had a contractile tail characteristic of Myoviridae. Restriction endonuclease analysis of NsiI and NdeI DNA fragments from one of the Siphoviridae phage isolates (phage phiEf11) indicated a genome size of approximately 41 kbp.
  
  
  CONCLUSIONS
  This is the first report of lysogenic bacteria and their inducible viruses in infected root canals.
authors: Department of Endodontology, Temple University Kornberg School of Dentistry, 3223 NorthBroad Street, Philadelphia, PA 19140, USA. rstevens@dental.temple.edu
authors: R H
authors: RH
authors: Stevens
authors: O D
authors: OD
authors: Porras
authors: A L
authors: AL
authors: Delisle
mesh_terms: D001435:Bacteriophages / Q000502:physiology; D004279:DNA, Viral / Q000032:analysis; D003786:Dental Pulp Cavity / Q000821:virology*; D019232:Dental Restoration Failure; D013293:Enterococcus faecalis / Q000187:drug effects / Q000821:virology*; D006801:Humans; D008242:Lysogeny / Q000187:drug effects; D016685:Mitomycin / Q000494:pharmacology; D017900:Myoviridae / Q000302:isolation & purification; D010485:Periapical Periodontitis / Q000821:virology*; D019233:Retreatment; D017906:Siphoviridae / Q000302:isolation & purification*; D019553:Tooth, Nonvital / Q000821:virology*; D014773:Virology / Q000379:methods; D014775:Virus Activation
chemical_list: D004279:DNA, Viral; D016685:Mitomycin