PHAGE THERAPY IN DENTISTRY: TREATMENT OF ANTIBIOTIC RESISTANT PERIAPICAL INFECTIONS

Enteroccocus faecalis is the third most prevalent nosocomial pathogen worldwide. Specifically, vancomycin-resistant enterococci (VRE) superbug was declared by the CDC as one of the most difficult organisms to treat. E. faecalis is frequently recovered from secondary persistent infections associated with root canal treatment failures. A possible solution to combat multidrug resistant bacteria is phage therapy. Phages are viruses that target bacteria and are considered as bacterial natural "professional killers". We isolated efficient phages against VRE known as EFDG1 and EFLK1. We hypothesized that phages cocktail would kill VRE in infected root canals in vivo.

Periapical lesions were induced by VRE in a root canal infection model on incisor teeth of male rats. Root canals were treated in a standard procedure. Test group included irrigation with phage cocktail and was compared to a control group. Microbiological samples were collected 3 weeks before and after treatment evaluating the bacterial number (CFU/mL), and the DNA of bacteria from the root canal were isolated. Three weeks after treatment periapical lesions were evaluated using microCT, histology, scanning electron microscopy, and the changes in the microbiota of the root canals were assessed.

Viable counts of VRE showed a significant killing of E. faecalis (˜3 logs reduction). MicroCT showed reduction in the periapical lesion size following phages treatment. Microbiota analysis showed that the phages cocktail changed the microbiota composition of the root canal, reducing the number of E. faecalis. Moreover, reduction in the inflammation of the periapical tissue was illustrated using SEM and histological analysis.

Phage therapy is a promising treatment against VRE in root canal periapical lesions in rat model.