Benefits and Challenges of the Use of Two Novel vB_Efa29212_2e and vB_Efa29212_3e Bacteriophages in Biocontrol of the Root Canal Enterococcus faecalis Infections

Abstract

Bacteriophage therapy has emerged as a strategy supplementing traditional disinfection protocols to fight biofilms. The aim of the study was to isolate the phages against E. faecalis and to characterize its biological features, morphology, and lytic activity in a formed biofilm model. Methods: E. faecalis ATCC 29212 strain was used for the trial. Two novel vB_Efa29212_2e and vB_Efa29212_3e virulent phages were isolated from urban wastewater and characterized. The E. faecalis biofilm was established in 15 bovine teeth for 21 days. Transmission (TEM) and scanning electron (SEM) microscopes with the colony-forming unit (CFU) counting were used for assessment. Results: Isolated phages differed in morphology. Taxonomy for vB_Efa29212_2e (Siphoviridae, Efquatovirus) and for vB_Efa29212_3e (Herelleviridae, Kochikohdavirus) was confirmed. Both phages were stable at a temperature range of 4–50 °C and showed a different tolerance to chemicals: 15% EDTA, 1-3% sodium hypochlorite, and chlorhexidine. SEM analysis showed distortion of bacteria cells after phage inoculation, which proved the lytic activity against E. faecalis. A 54.6% reduction in the E. faecalis biofilm confirmed bacteriophage efficacy against isolates in the ex vivo model. Conclusions: Results strongly support the concept that phage therapy has a real therapeutic potential for the prevention and treatment of E. faecalis-associated infections.

How Do Phages Disrupt the Structure of Enterococcus faecalis Biofilm?

“…In the presented work, two aspects were analyzed: how the phages interact with bacterial cells and how their activity influences the level of individual matrix components like extracellular polysaccharides, proteins, and DNA. In this study, the effects of the phages previously characterized by the authors, vB_Efa29212_2e and vB_Efa29212_3e, applied separately and in combination on 1-day and 7-day-old biofilms were evaluated [21]. Two variants of biofilms, which differed in their degree of maturity, were studied.…”

“…Our study confirmed that phages had different effects on planktonic and biofilm forms of bacteria, and the maturity of the biofilm structure played a crucial role in the phage activity. We used two phages with different biological features [21]. Phages 2e were distinguished by a smaller virion size, a shorter latency period, and a higher burst size compared to phages 3e and demonstrated effectiveness against planktonic E. faecalis forms.…”

“…The filtered sewage samples were mixed with an equal volume of 2 × concentrated BHI and with E. faecalis culture. The sample was incubated at 37 • C for 24 h, then centrifuged (3600× g for 30 min) and filtered through a sterile filter (0.2 µm) [21]. The isolated phages were characterized.…”

“…The isolated phages were characterized. The morphology of phages and their biological features were determined, and the genome analysis was carried out [21]. Bacteriophage lysates with a titer of 10 9 were stored at 5 • C.…”

Efficacy of Calcium Hydroxide/Saline versus Calcium Hydroxide/Artemisia persica Essential Oil as Intracanal Medicament to Improve Radiographic Visualization of Periapical Lesions in Necrotic Teeth: A Randomized Clinical Trial

“…The main purpose of endodontic treatment is to eliminate the bacteria and necrotic products from the root canal system and prevent the leakage of microorganisms into the periapical tissue. However, despite optimal cleaning and shaping, some resistant bacterial species may remain in the root canal system and cause refractory infections [ 1 , 2 ].…”