O17 Effect of Probiotic Streptococcus salivarius K12 on oral malodour parameters

Objective Recent non‐cultural‐based studies of the oral microbiota indicate that some subjects with halitosis are less likely to have the usually predominant commensal bacterium Streptococcus salivarius detected [J Clin Microbiol (2003) 41(2): 558–563.]. The aim of this study was to determine whether the oral delivery of viable bacteriocin‐producing S. salivarius could influence the composition of the oral microbiota implicated in halitosis and impact upon measurable parameters of malodour. Methods Thirteen subjects with volatile sulphur compound (VSC) breath readings of >200 ppb on two separate visits were recruited for the study. The subjects undertook a 3‐day regimen of chlorhexidine rinses followed at intervals by the sucking of four lozenges, each containing >1 × 109 colony forming units of the bacteriocin‐producing S. salivarius K12. The subjects then ceased using the chlorhexidine and took just two lozenges per day for a total of 2 weeks. At each pre‐treatment visit and at 1 and 2 weeks after treatment initiation the subjects were tested for VSC and both saliva samples and tongue swabs were subjected to BANA testing, microbial culture and PCR‐denaturing gradient gel electrophoresis (PCR‐DGGE) analysis. All measurements were taken in the morning prior to the subjects eating, drinking or using any oral care. The ability of the bacteriocins produced by S. salivarius K12 to inhibit bacteria implicated in halitosis was tested in vitro by deferred antagonism tests using pure cultures and saliva samples. Results and discussion The VSC levels of eight subjects were significantly lower when tested 1 and 2 weeks after commencing treatment, three subjects had lower readings only after 1 week and two subjects maintained high levels throughout the study. Reduction of BANA activity and changes in the PCR‐DGGE profiles occurred in most subjects following treatment. In deferred antagonism studies, S. salivarius K12 inhibited some of the bacterial species implicated in halitosis, and significantly inhibited black‐pigmented colony types in saliva samples. Conclusions The replacement of bacteria implicated in halitosis with the bacteriocin‐producing commensal bacterium S. salivarius K12 appears to provide an alternative therapy for the long‐term reduction of halitosis.