ObjectiveTo screen small-molecule antibacterial drugs and investigate the antibacterial effect and mechanism of selective estrogen receptor modulators (SERMs) againstStreptococcus mutans (S.mutans).
MethodsThe minimum inhibitory concentration of 426 Food and Drug Administration (FDA)-approved small-molecule drugs againstS. mutanswas determined using the microdilution method, and the target of SERMs acting onS. mutanswas explored by employing a random transposon mutant library.
ResultsAmong the 426 FDA-approved SERMs, toremiphene, tamoxifen, clomiphene, and raloxifene exhibited excellent antibacterial effects againstS.mutans. Results of mutant library screening showed that the two mutant strains were resistant to clomiphene. The gene sequence of the resistant strains showed that the transposon insertion sites were located in the genes ofsmu_546andsmu_874.
ConclusionSERMs, such as toremifene, tamoxifen, clomiphene, and raloxifene, exerted obvious antibacterial effects onS. mutans, and their targets may be proteins expressed bysmu_546andsmu_874gene.
