Antimicrobial and antibiofilm activity of pleurocidin against cariogenic microorganisms.
Department of Operative Dentistry and Endodontics, School of Stomatology, Fourth Military Medical University, Xi'an 710032, People's Republic of China.
Dental caries is a common oral bacterial infectious disease of global concern. Prevention and treatment of caries requires control of the dental plaque formed by pathogens such as Streptococcus mutans and Streptococcus sobrinus. Pleurocidin, produced by Pleuronectes americanus, is anantimicrobial peptide that exerts broad-spectrum activity against pathogenic bacteria and fungi. Moreover, pleurocidin shows less hemolysis and is less toxic than other natural peptides. In the present study, we investigated whether pleurocidin is an effective antibiotic peptide against commoncariogenic microorganisms and performed a preliminary study of the antimicrobial mechanism. We assayed minimal inhibitory concentration (MIC), minimal bactericide concentration (MBC) and bactericidal kinetics and performed a spot-on-lawn assay. The BioFlux system was used to generate bacterial biofilms under controllable flow. Fluorescence microscopy and confocal laser scanning microscopy (CLSM) were used to analyze and observe biofilms. Scanning electron microscopy was used to observe the bacterial membrane. MIC and MBC results showed that pleurocidin had different antimicrobial activities against the tested oral strains. Although components of saliva could affect antimicrobial activity, pleurocidindissolved in saliva still showed antimicrobial effects against oral microorganisms. Furthermore, pleurocidin showed a favorable killing effect againstBioFlux flow biofilms in vitro. Our findings suggest that pleurocidin has the potential to kill dental biofilms and prevent dental caries.
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