Different expression of mrna of lux-s in low and high caries risk of pre-school children

The luxS mRNA expressing autoinducer-2 (AI-2) is maintained among many species of bacteria, including Streptococcus mutans. AI-2 plays a decisive promoting role in biofilm formation and maturation. The aim of this study was to determine the luxS mRNA expression in relation to caries status and caries activity among pre-school children. The cross-sectional study included 76 pre-school children (31 boys and 45 girls) aged 3 to 5 years old, from a kindergarten in Jakarta, Indonesia. The children were screened for caries status using dmft index. Dental plaque samples were obtained for caries activity screening using Cariostat, and for luxS mRNA expression determination using quantification real time-PCR (qPCR). Out of 76 subjects examined luxS mRNA expression was determined in 43 subjects. We divided the subjects with luxS mRNA expression into two groups: group 1 consisted of children who are caries free (dmft zero) and had no caries activity (Cariostat score 0); group 2 was comprised of children with caries and caries activity were scored as1 and above. There were 9 subjects in group 1 and 34 subjects in group 2, and the mean ± SD of luxS mRNA expression was determined to be 19.3±24.3 ng/mL and 41.7±29.1 ng/mL, respectively, and statistically different (p = 0.03). It can be concluded that the amount of luxS enzyme was lower in the caries free and no caries activity subjects compared to subjects with caries and caries active.