Molecular Detection of Enterococcal Surface Protein (esp) Gene in Enterococcus faecalis Isolated from Dental Calculus of Patients in Sari, Iran

Background: Enterococci are important gram-positive bacteria causing dental calculus in human beings; however, the role of these bacteria in oral cavity is unclear. The aim of this study was to investigate the presence of Enterococcal Surface Protein (esp) gene in Enterococcus faecalis isolated from dental calculus in the city of Sari, Iran. Materials and Methods: In the present study, 207 dental calculus samples were collected from patients. The isolates were identified by growth on Bile Esculin agar, Gram stain, Catalase test, Growth at 6.5% NaCl, PYR and arabinose fermentation test. Antimicrobial susceptibility pattern of the isolates was determined by disk agar diffusion method. The presence of esp gene was assessed by polymerase chain reaction (PCR). Results: Among the 56 (27%) enterococci isolated from dental calculus, 43 (76.7%) were determined as E. faecalis. The resistance rate to ampicillin, vancomycin, tetracycline, ciprofloxacin and erythromycin in E. faecalis isolates was estimated as 13.9%, 4.6%, 11.6%, 6.9% and 13.9%, respectively. The esp gene was detected in 18.6% of E. faecalis isolates. Among the isolates containing esp gene, 33.3%, 50%, 40%, 33.3% and 33.3% of them were resistant to ampicillin, vancomycin, tetracycline, ciprofloxacin and erythromycin, respectively. Conclusion: E. faecalis is an important organism causing dental calculus but the presence of esp gene had no correlation with the resistance to tested antimicrobial agents.