Evaluation for acidogenic capacity of oral cariogenic bacteria through bacterial co-aggregation recognition

The acidogenic capacity of oral cariogenic bacteria is closely related with the occurrence and development of dental caries. In this work, a novel strategy is innovatively proposed to evaluate the acidogenic capacity of cariogenic bacteria in virtue of coaggregation recognition between bacteria to accelerate acid production. Taking Streptococcus mutans as an example of oral bacteria, it has been found to co-aggregate with Bacillus camelliae 7578-1 T , a fermentation bacterium from Pu’er tea. Based on co-aggregation interaction, a metabolic substrate of S. mutans , 7578-1 T @PDBA@Mal, is prepared to load maltose (Mal) onto 7578-1 T with 1, 4-phenylenediboronic acid (PDBA) as a linker and it exhibits an initial rate of acid production that is 3.26 times higher, in comparison with that of the free Mal with the same amount. By using 7578-1 T @PDBA@Mal as metabolic substrate, the method has been established to evaluate acidogenic capacity of S. mutans with a linear range from 10 2 to 10 8  CFU/mL and a detection limit of 656 CFU/mL. The established method gives an area under the ROC curve of 0.99 by analyzing clinical saliva samples treated through centrifugation and resuspension. At the same time, Bland-Altman analysis also demonstrates high consistency with qPCR results. Moreover, the established method significantly reduces equipment dependency and saves detection time. With the ingenious usage of bacterial co-aggregation recognition to construct metabolic substrates, this strategy demonstrates a cost-effective, rapid, and simple approach that holds significant potential for precise risk assessment of dental caries.