Identification of a novel bacterium Scardovia wiggsiae in high caries risk adolescence: A metagenomic and melt curve analysis

BACKGROUND: Mutans streptococci which comprise only 2% have long been presumed to be the specific pathogen responsible for caries. A novel caries associated bacterium namely Scardovia wiggsiae is recognized to be ecologically competitive in active caries lesions. The actual pathogen needs to be identified, so as to specifically target and reduce the prevalence of caries in a given community. AIM: The aim of the study is to evaluate the presence of S. wiggsiae in combination with other bacteria in caries risk adolescence. METHODS: Sixty adolescent subjects were screened. Phase I-to determine the prevalence of S. wiggsiae in saliva, plaque and dentinal caries samples of low and high caries risk individuals (n = 30 each) using polymerase chain reaction (PCR); Phase-II-to identify its presence by 16SrRNA metagenomic analysis and quantitatively evaluate the cariogenic pathogen using high-resolution melt curve analysis and real-time PCR. RESULTS: Highest prevalence of S. wiggsiae was observed in dentinal caries followed by plaque and saliva samples of high caries risk individuals under PCR analysis. Metagenomic analysis showed two-fold statistically increased presence of Lactobacilli and Bifidobacteriaceae (S. wiggsiae) in dentinal samples compared to plaque samples (P = 0.05). Mutans streptococcus recorded the minimum. CONCLUSION: Scardovia wiggsiae is identified as one of the predominant microorganism.