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

Abstract

Objective: Comparative evaluation of various media compositions for Streptococcus mutans (Strep. mutans) best propagation, pointing out the diversity in Strep. mutans clinically isolated from patients with different caries behavior and ages using molecular tools. Methods: The case control study included ninety outpatients from Faculty of Dentistry, October University for Modern Sciences and Arts, Cairo, Egypt, that were divided into three age groups (3-5, 6-12 and 18-25 years). Each group was subdivided according to the caries behavior into caries free and active subgroups. Salivary samples were collected. Six culture media were used to plate the diluted saliva. They were Mitis Salivarius and tellorite (MST), Mitis Salivarius, bacitracin and kanamycin (MSBK), Mitis Salivarius, bacitracin and tellorite (MSBT), Trypticase media, glucose, sucrose, tellurite, and bacitracin (GSTB) and yeast, cysteine, sucrose and bacitracin (YCSB) agars. Polymerase Chain Reaction technique was used to detect Strep. mutans using primers. Total protein profiles were analyzed through polyacrylamide gel electrophoresis. Results: GSTB media yielded the highest percentage of Strep. mutans colonies. Regarding the protein profile, proteins (43, 51, 65, 74 and 87 kDa) were significantly less detected in 18-25 age group compared to the other groups. About the caries activity, there was a significant difference in 122 and 170 kDa (P = 0.01) between caries free and active participants. Conclusions: Media structure may play significant role in Strep. mutans recovery. Protein bands were less commonly observed in young adults, but the inserting result showed that only two bands were found to differentiate between caries active and free participants.

Bacteriophage Endolysins Antibacterial Effect against S. mutans Isolated from Dental Caries: An In-Vitro Study

“…The plaques were counted by top layer agar plaque assay to determine the phage titer, morphological characteristics, edge, clarity and size. Furthermore, top layer plaque assay is the best way used for getting highest titers of phage suspensions [10,11]. The phage titer was calculated by using the following formula:…”

“…Assay of endolysin antibacterial activity: The bacterial broth titer was measured using serial dilution, then 10 µl (0.01 ml) of each dilution were spotted on nutrient agar, then incubated in 10 % CO2 at 37 °C for 48 hours. After incubation, the dilution plate that was showed countable separated colonies was used to calculate the bacterial titer (obtaining 0.5 McFarland) using the following equation [10,14].…”

“…The reduction in the titer of the bacterial broth with endolysin compared to the same broth without endolysin was measured. The endolysin antibacterial activity was quantified in log units decrease [10,15].…”