Isolation and identification of lytic bacteriophage against Enterococcus faecalis isolated from root canals of decayed teeth

BACKGROUND AND OBJECTIVESEnterococcus faecalis, one of the most important causes of infection in the root canal of the tooth with a prevalence between ۲۴-۷۷%. Its removal is difficult because it is capable of formation of biofilm and resistant to antibiotics. Sometimes they remain even after treatment with disinfectants and mechanical removal. Therefore, it is necessary to use alternative methods. Bacteriophages can be a powerful, healthy and useful tool. Bacteriophages as a novel and powerful tool can be useful and valuable for treatment-resistant infections. The aim of this study was isolation and identification of a lytic bacteriophage against Enterococcus faecalis strains from the decayed tooth canal and determined by biological characteristics.MATERIALS AND METHODSIn this study, a sample was taken from the root canal to isolated Enterococcus faecalis and it was cultured in Mitis salivarius agar medium. Suspected Enterococcus faecalis isolates were confirmed by biochemical tests and PCR and were deposited in Genebank. A lytic bacteriophage against Enterococcus faecalis was isolated from wastewater in East of Isfahan, Iran. The effects of temperature, pH values, NaCl concentrations, adsorption rate, burst size, multiplicity of infection (MOI), efficiency of plating (EOP) and host range were investigated on the bacteriophage. Data were analyzed by GraphPad Prism version ۸.۰ software (GraphPad Software Inc., USA) using one-way analysis of variance (ANOVA).RESULTS AND DISCUSSIONThe bacteriophage was effective against a wide range of Gram-negative and Gram-positive bacteria and showed a high efficiency of plating (EOP ≥۰.۵) in about ۸۱% of the Enterococcus faecalis isolates. The bacteriophage was stabled in an almost wide range of temperature (-۲۰–۵۰°C), pH values (۶-۱۱), and NaCl concentrations (۱-۱۰%). Also, the bacteriophage was a short latent period (۱۰ min) with a large burst size (۱۲۵ p.f.u. cell-۱) and appropriate lytic activity especially at high MOI.CONCLUSIONIn this study, we isolated a novel Enterococcus faecalis phage with broad lytic activity, which based on biological properties investigated, this bacteriophage can be used as a suitable choice for genomic studies in preparation for commercialization in the direction of phage therapy.

کلیدواژه ها:

Enterococcus faecalis ، lytic bacteriophage ، Root canals ، Phage therapy