Abstract

THE ROLE OF SOME VIRULENCE FACTORS OF STREPTOCOCCUS MUTANS BACTERIA ISOLATED OF PATIENTS WITH DENTAL DISEASES IN HILLA CITY

*Moayad N. M, Ilham A.Bnyan, Hayam K.A and Mahdi Y.Kezar

Abstract

Streptococcus mutans is considered the major and the etiological agent of human tooth decay. It is an obligate biofilm – forming bacterium, which resides on teeth and forms together with other species, an oral biofilm that is frequently designated as superagingival plaque. Streptococcus mutans has virulence factors to help to protect the bacterium against possible defenses and maintain its ecological niche in the mouth. Possible virulence factors include: adhesions, acid production, acid tolerance, production of glucosyltransferase GTFs, biofilm formation, capsule, dextranase, and mutacin production, lead to dental infection. This study included (100) samples which were collected from patients suffering from dental diseases, (50) samples taken from patients infected with dental caries and (50) samples taken from patients with periodontal diseases, who have admitted to a collage of Dentistry in Babylon university and special center of Dentistry. (30) Samples were taken from healthy persons as control, during the period from the first of November 2014 to end of April 2015 in Al-Hilla city. The isolation and identification of S.mutans was performed by Mitis- Salivarius Bacitracin agar as a selective medium and biochemical tests.The result showed that 24 (24%) of samples revealed positive growth of S.mutans . The virulence factors of S.mutans isolated in this study were studied and it was seen that the (58.3%) of isolates were made capsule and (100 %) were its ability to synthesize glucan, (83.3%) of S.mutans isolates were able to produce mutacin and (45.83%) of isolates were found to produce dextranase enzyme, while (84%) were able to biofilm formation in addition, all isolates in this study were able to adhere to oral epithelial cells.Finally the most isolates are able to produce many virulence factors involving, mutacin, glucan as well as adhere to the tooth surface of human (biofilm),dextranase, capsule and adherence ability to oral epithelial cells.

Keywords: Dental diseases, Streptococcus mutans, GTFs, Capsule, Dextranase, Biofilm formation, Mutacin production, Adhesive properties.