Evaluation of selective mitis salivarius agar for the isolation of Streptococcus mutans and its resistance pattern in Bangladesh

Since Streptococcus mutans appears to be the most common cause of dental caries, appropriate laboratory media is necessary for the proper detection and management of this bacterium. The aim of this study was to evaluate the mitis salivarius agar (MSA) compared to conventional blood agar media (BAM) for detection of bacterium. This study was conducted in the Department of Microbiology of the Rajshahi Medical College, Rajshahi, Bangladesh from April 2017 to December 2017. The sample, dental swab was taken from 200 children, aged between 6-18 years who underwent dental caries and residing in Rajshahi district. All specimens were cultured to identify and compare the morphologic characteristics of its colonies both in MSA and BAM. In this study, antimicrobial susceptibility testing was also performed. This prospective observational study was conducted through regular and continuous monitoring of the results. Out of 200 specimens, the growth rate was 82%. Higher growth was observed in MSA (39.5%) than BAM (24.1%). Of them, we found 53.1% multi-drug resistant mutans. The most resistance was to Penicillin G (100%) followed by Azithromycin (95.3%). The study findings would help to increase the detection of mutans and its pattern for proper treatment towards the improvement of children's dental health in Bangladesh.