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.


OBJECTIVE
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).


CONCLUSIONS
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.
Dental Public Health, Faculty of Dentistry, the University of Hong Kong, Hong Kong, China. gaoxl@hkucc.hku.hk
Xiao-Li
XL
Gao
Chaminda J
CJ
Seneviratne
Edward C M
EC
Lo
Chun Hung
CH
Chu
Lakshman P
LP
Samaranayake
D000911:Antibodies, Monoclonal; D002675:Child, Preschool; D015331:Cohort Studies; D015169:Colony Count, Microbial; D003731:Dental Caries / Q000175:diagnosis / Q000382:microbiology*; D003732:Dental Caries Activity Tests / Q000379:methods*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D015203:Reproducibility of Results; D012463:Saliva / Q000382:microbiology*; D012680:Sensitivity and Specificity; D013295:Streptococcus mutans / Q000276:immunology / Q000302:isolation & purification*
D000911:Antibodies, Monoclonal