Bacteriological evaluation of mutans streptococci using modified mitis-salivarius-bacitracin (MSB) agar medium in primary dentition period

Abstract

Mutans streptococci considered causative agents of dental caries are indigenous to the oral cavity. Modified mitis-salivarius-bacitracin (MSB) agar medium was supplied by BML. This media has characters to grow mutans streptococci very well and to inhibit of non-mutans streptococci. However, little is known about studies using this medium. In this study, we assessed the utility of modified MSB medium and discuss the relation between mutans streptococci and dental caries in primary dentition period. Modified MSB medium was found to be a suitable medium to isolate and quantify mutans streptococci since it could permit selective growth of mutans streptococci. Moreover, this medium inhibited to non-mutans streptococci (S. anginosus and S. intermedius), completely. The detection rate of Streptococcus mutans and Streptococcus sobrinus increased in proportion to the severity of dental caries in the nursery children. From these results, modified MSB agar medium is useful in the judgment to detect the mutans streptococci. mitis-salivarius-bacitracin (MSB) agar 9) (MS agar containing 200 U of bacitracin and 15% sucrose per liter) have been developed. However, non-mutans streptococci were found to form the colonies as well as mutans streptococci in these selective media 10) . Then modified MSB medium containing three kinds of antibiotics (2 mg of gramicidin D, 10 mg of colistin, and 10 mg of nalidixic acid per liter) in addition to bacitracin was supplied by BML (Tokyo, Japan) 11) . In this medium mutans streptococci can grow well, but only poor growth of non-mutans streptococci is permitted. Furthermore, S. mutans and S. sobrinus are distinguishable (by naked eyes) based on the different properties of colonies on modified MSB agar. The aim of this study is to assess the utility of this medium and discuss the relation between mutans streptococci and dental caries in primary dentition period.

Molecular assessment of oral Streptococcus mutans isolated from patients with different ages and caries activity via selective media and protein pattern

“…mutans. This was in accordance to Saito et al 25 . Kanamycin was added as it increases the effect of bacitracin by restraining the growth of microorganisms other than Strep.…”

Increasing salivary IgA and reducing Streptococcus mutans by probiotic Lactobacillus paracasei SD1: A double-blind, randomized, controlled study

“…It revealed that either short-term or long-term consumption of milk-powder containing L. paracasei SD1 could reduce salivary cariogenic mutans streptococci resulting in low caries risk 7, 8, 9, 10. Those studies used a selective agar, modified mitis salivarius bacitracin agar, to distinguish Streptococcus mutans and Streptococcus sobrinus as a mutans streptococci group from other streptococci; however, it may not clearly distinguish those two species from each other 11 . Other limitations of the cultivation method such as low sensitivity and variation in growth conditions call for using other methods to confirm previous results 12 , 13 .…”

Antimicrobial Peptide GH12 Prevents Dental Caries by Regulating Dental Plaque Microbiota

“…The rats were treated with antibiotics (by use of a diet containing 0.1% ampicillin, 0.1% chloramphenicol, and 0.1% carbenicillin and water with 4,000 U/ml penicillin) for 3 days (43), during which they were offered standard laboratory chow (Trophic, Nantong, China) and sterile distilled water ad libitum (44). The rats were then infected orally with S. mutans UA159 for 3 days, and the infection was confirmed by oral swabbing and culturing on mitis-salivarius-bacitracin agar plates (45,46). The infected animals were randomly assigned to one of two groups: the DDW group and the GH12 group.…”