Abstract

Background- Enterocins are antimicrobial peptides produced by Enterococcus species, which have inhibitory activity on closely related genera. Streptococcus mutans has been implicated as a pivotal organism to initiate dental caries ensuing, serious impairment to structure and functions of tooth beside the mental health of humans. Hence we investigated the possibility of using enterocins in caries treatment and prophylaxis. Methods- S. mutans was isolated from the saliva of 50 caries-prone humans. Enterococcus faecalis were isolated from the stool samples of humans. The species identity of the isolated organisms was confirmed using conventional biochemical methods. The inhibitory activity of enterocins on S. mutans isolates and their active concentrations was identified by spot-on-lawn assay. Inhibitory activity of 3 enterocins on their target S. mutans isolates were further analyzed by time-kill assay and colony forming units (CFU)/ml over 0, 4, 8 and 12 h time interval was determined. Results- Enterocins produced by three E. faecalis isolates demonstrated inhibitory activity on more than 75% of S. mutans isolates. Enterocins SF101, enterocin SF118 and enterocin PF98 showed 100% inhibition of their target S. mutans at 1:2, 1:4, and undiluted concentrations. The viable count of enterocin treated S. mutans isolates declined to mean log10 CFU/ml of 4.92 after 12 h time interval while the untreated control showed the increase to 9.11. Conclusion- Enterocins exerts bactericidal activity against S. mutans, thus validating the possibility of enterocin to be used for caries treatment and prophylaxis.

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