Novel and conventional assays in determining abundance of Streptococcus mutans in saliva.

BACKGROUND

Effective caries control and management requires identification of susceptible children for timely intervention. Streptococcus mutans (S. mutans) is an important biomarker of caries risk.

AIM

This study aimed to comparatively evaluate the validities of a novel immunoassay and a conventional culture-based assay in detecting salivary S. mutans in a paediatric cohort.

METHODS

190 children aged 3-4 years were recruited. The abundance of S. mutans in their saliva samples was analysed with three assay systems viz. a conventional culture-based assay (Dentocult SM), a novel immunoassay system (Saliva-Check MUTANS) based on monoclonal antibody technology and a Taqman real-time PCR assay taken as a gold standard.

RESULTS

The novel immunoassay accurately differentiated saliva samples with high (≥5 × 10(5) CFU/mL) and low (<5 × 10(5) CFU/mL) S. mutans levels. The sensitivity/specificity was 97.6%/90.6%. The conventional culture-based assay reached a reasonably high sensitivity/specificity (92.8%/81.3%) in identifying children with moderate (≥10(4) CFU/mL) S. mutans level. Its sensitivity/ specificity in selecting children with high (≥10(5) CFU/mL) and very high (>10(6) CFU/mL) S. mutans levels were not sufficient (78.7%/79.8% and 25.8%/91.8%, respectively).

CONCLUSION

The monoclonal antibody-based immunoassay accurately and rapidly determines S. mutans abundance in saliva and could be useful for chairside assessment of children's caries risk.