Antibacterial Activity of a Lysin LysP53 against Streptococcus mutans .

Dental caries is a common disease affecting quality of life globally. In the present study, we found that a bacteriophage lysin LysP53 against possesses selective activity on , the main etiological agent of dental caries, even in low pH caries microenvironments, whereas only minor LysP53 activity was detected against , , and . Testing activity against planktonic cells showed that 4 μM LysP53 could kill more than 84% of within 1 min in buffer with optimal pHs ranging from 4.0 to 6.5. Daily application of LysP53 on biofilms formed in BHI medium supplemented or not with sucrose could reduce exopolysaccharides, expression of genes related to acid resistance and adhesion, and the number of live bacteria in the biofilms. LysP53 treatment also showed similar effects as 0.12% chlorhexidine in preventing enamel demineralization due to biofilms, as well as effective removal of colonization of tooth surfaces in mice without observed toxic effects. Because of its selective activity against main cariogenic bacteria and good activity in low pH caries microenvironments, it is advantageous to use LysP53 as an active agent for preventing caries.