A lacticin 3147 enriched food ingredient reduces Streptococcus mutans isolated from the human oral cavity in saliva

Abstract

Aims: To isolate and characterise Streptococcus mutans from Irish saliva samples and to assess their sensitivity to a food‐grade preparation of the lantibiotic, lacticin 3147, produced by Lactococcus lactis DPC3147. Methods and Results: Saliva samples collected from children with varying oral health status were screened on Mitis Salivarius agar for the presence of pathogenic streptococci. Following selective plating, 16S rDNA sequencing and Pulsed Field Gel Electrophoresis (PFGE), 15 distinct strains of Strep. mutans were identified. These were grouped according to their relative sensitivity to lacticin 3147 which ranged from 0·78 to 6·25%; relative to a sensitive indicator strain, Lactococcus lactis ssp. lactis HP. Inhibition of indicator Strep. mutans strains from sensitive, intermediate and tolerant groupings were assessed in microtitre plate assays with increasing concentrations of lacticin 3147. The concentration of lacticin 3147 required to give 50% growth inhibition correlated with their relative sensitivities (as assayed by well diffusion methodology) and ranged from 1280 to 5120 AU ml−1. Concentrated preparations of lacticin 3147 caused a rapid killing of Strep. mutans strains in broth. Moreover, in human saliva deliberately spiked with Strep. mutans, the pathogen was eliminated (initial inoculum of 105) in the presence of 40 000 AU ml−1 of lacticin 3147. Furthermore, a food‐grade lacticin 3147 spray dried powder ingredient was assessed for the inhibition of Strep. mutans in human saliva, spiked with a strain of intermediate sensitivity, resulting in up to a 4‐log reduction in counts after 20 min. Conclusion: A food grade preparation of lacticin 3147 was effective in the inhibition of oral Strep. mutans. Significance and Impact of the Study: The inhibition of oral streptococci by food grade preparations of lacticin 3147 may offer novel opportunities for the development of lacticin 3147 as an anti‐cariogenic agent particularly in the area of functional foods for the improvement of oral health.

Characterization and application of an anti-Listeria bacteriocin produced by Pediococcus pentosaceus 05-10 isolated from Sichuan Pickle, a traditionally fermented vegetable product from China

“…Bacteriocin activity was determined by the well-diffusion method (O'Connor et al, 2006) using L. monocytogenes 54002 as the indicator strain. The activity of cell-free supernatant was expressed in arbitrary units per ml (AU/ml).…”

Are Bacteriocins Underexploited? NOVEL Applications for OLD Antimicrobials

“…E. faecalis is gaining attention in dentistry as it can be isolated in obtruded root canals with signs of chronic apical periodontitis [133,134], and sometimes as the only species in antibioticresistant infections [135]. As noted above, enterococci are resistant to many antibiotics and can be effectively treated by mouth rinse with bacteriocin solutions.…”

Two-Peptide Lantibiotics: A Medical Perspective

“…The genes responsible for production of staphylococcin C55 are carried on a 32kb plasmid and curing of this plasmid at elevated temperatures leads to the loss of antimicrobial activity. This in itself is a testament to the high degree of relatedness between the two sets of structural peptides [74]. a 37Kb plasmid located in S. aureus U0007 [72] and a 38Kb plasmid in S. aureus TY4 [73].…”

“…Experimental studies have verified its effectiveness in the treatment of mastitis in cattle. More recently lacticin 3147 has also been found to be effective against 15 different cariogenic strains, indicating that it may be exploited in the future for the prevention of dental caries [74]. It may be construed from this that lacticin 3147 may also be effective in the treatment of S. dysgalactiae in humans; this microorganism has been implicated in the occurrence of acute pharyngitis in children [85] and has also been implicated in a case of bacteraemia in a patient with pyomyositis and reactive arthritis [86].…”