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

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 glucosyltransferase 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 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 was that only two bands were found to differentiate between caries active and free participants.