Isolation and identification of fluoride sensitive and fluoride resistant Streptococcus mutans strains from dental carries of diabetic patients using conventional methods in Sudan.

Abstract

Background Dental caries also known as cavities are the most predominant disease today. Streptococcus mutans can form a biofilm on the tooth surface, produce high levels of lactic acid following fermentation of dietary sugars, and are resistant to the adverse effects of low pH, properties which are essential for oral micro biota. The aim of this study was to isolate S. mutans and characterize their antimicrobial properties against sodium fluoride. Fresh dental caries samples were collected from diabetic patients. The isolates were identified based on their acidogenic, biochemical test, and antimicrobial properties. Methods The socio-demographic data collected through a structure designated questionnaire and the biological data collected through sterile cotton swabs. For analysis of data, Statistical Package for Social Sciences software, version 23.0 (IBM SPSS Inc., Chicago, IL) was used. Results Only 32 of the 80 samples (40%) gave a positive growth for S. mutans on MSBA (mitis salivarius bacitracin agar). The sensitivity of the isolates against sodium fluoride was tested by preparing NaF of four different concentrations (80, 125, 250, and 500) mg\L. Fifty percent of isolates were found to be resistant to NaF at a concentration of 80 mg/L, while 28% were resistant to 125 mg/L NaF, 16%   to 250 mg/L and 3% to 500mg/L NaF. The majority of the participants were aged between 51–60 years (33%), were female (54%), had type II diabetes mellitus (64%), and the duration of their diabetes was less than five years (35%). Conclusions By using the information in this study, we were able to discover strains of S. mutans that are resistant to fluoride. This study can be used as an essential key to study the genetic mutation that occurred.