en ميکروبيولوژي Microbiology پژوهشي Research <p style="text-align: justify;"><strong>Background:</strong> 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 (<em>esp</em>) gene in <em>Enterococcus faecalis</em> isolated from dental calculus in the city of Sari, Iran.<br> <strong>Materials and Methods:</strong> 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 <em>esp</em> gene was assessed by polymerase chain reaction (PCR).<br> <strong>Results:</strong> Among the 56 (27%) enterococci isolated from dental calculus, 43 (76.7%) were determined as <em>E. faecalis</em>. The resistance rate to ampicillin, vancomycin, tetracycline, ciprofloxacin and erythromycin in <em>E. faecalis</em> isolates was estimated as 13.9%, 4.6%, 11.6%, 6.9% and 13.9%, respectively. The <em>esp</em> gene was detected in 18.6% of <em>E. faecalis </em>isolates. Among the isolates containing <em>esp</em> gene, 33.3%, 50%, 40%, 33.3% and 33.3% of them were resistant to ampicillin, vancomycin, tetracycline, ciprofloxacin and erythromycin, respectively.<br> <strong>Conclusion: </strong><em>E. faecalis</em> is an important organism causing dental calculus but the presence of <em>esp</em> gene had no correlation with the resistance to tested antimicrobial agents.<br> &nbsp;</p> Enterococcus faecalis, Dental Calculus, esp gene, PCR 21 25 http://rmm.mazums.ac.ir/browse.php?a_code=A-10-26-34&slc_lang=en&sid=1 Mona Akhondnezhad monaakhondnezhad@gmail.com 10031947532846006770 10031947532846006770 No 1 Department of Microbiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Mazandaran, Iran Mehrnaz Bakhti mehrnazbakhti@gmail.com 10031947532846006771 10031947532846006771 No 1 Department of Microbiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Mazandaran, Iran Mohtaram Nasrolahei mnasrollahei@yahoo.com 10031947532846006772 10031947532846006772 No 1 Department of Microbiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Mazandaran, Iran Bizhan Shabankhani shabankhani@yahoo.com 10031947532846006773 10031947532846006773 No Faculty of Health, Mazandaran University of Medical Sciences, Mazandaran, Iran Hamid Reza Goli goli59@gmail.com 10031947532846006774 10031947532846006774 Yes 1 Department of Microbiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Mazandaran, Iran