Molecular investigation of enterococcal surface protein (esp) gene of Enterococcus faecalis isolated from endodontic patients

Abstract

Objective. Enterococci are generally considered transient components of oral bacteria that may be a reason for several oral and systemic infections, particularly those related to dental root canal infections. The current study aims to examine the occurrence of Enterococcus surface protein, esp in Enterococcus faecalis, which is isolated from infected root canals. Methods. Forty samples were collected from endodontic patients who attended the Conservative Treatment Department in the College of Dentistry/Mosul University/Dental Teaching Hospital. Materials and Methods: All samples were traditionally examined using HiCrom TM Enterococcus faecium Agar base medium and biochemical tests. 16srRNA sequencing was performed using the polymerase chain reaction technique to confirm their identity. Then, all Enterococcus faecalis isolates were examined for the existence of esp gene coding for enterococcal surface protein using PCR assay. Results. From 40 clinical samples obtained, 31 isolates were recognized as E. faecalis by traditional methods; unexpectedly, other non-enterococci genera were also grown on HiCromTM Enterococcus faecium Agar base medium. The PCR products for the sequence-specific primers obtained from the full-length of 16S rRNA gene sequence, which belongs to E. faecalis, and the PCR products for specific primer of esp genes created bands at the position of 138bp and 932 bp on the agarose gel, respectively. The gene correlating with the aggregation of this bacteria on the canal walls was detected in a high proportion (91%) of the isolates. Conclusions. PCR assay provides an accurate, rapid, and more sensitive detection of E. faecalis. A positive correlation between esp gene and enterococcal infections in root canals has been found.