Effective oral health in infective endocarditis: efficacy of high-street mouthwashes against the viridans group streptococci.

Aim: Recent UK National Institute for Health and Clinical Excellence guidelines state that there is no longer a need for oral antibiotic prophylaxis in patients undergoing dental procedures who are at risk of infective endocarditis (IE), and advocate the importance of maintaining good oral health. As viridans group streptococci (VGS) are common etiological agents of IE and inhabitants of the mouth, the purpose of this study was to examine the efficacy of common high-street mouthwashes against four classes of VGS organisms (salivarius, mitis, anginosus, and mutans groupings).

Methods: The survival of VGS, Streptococcus gordonii (National Collection of Type Cultures [NCTC] 7865), Streptococcus intermedius (NCTC 11324), Streptococcus mutans (NCTC 10449), Streptococcus oralis (NCTC 11427), Streptococcus pneumoniae (NCTC 7465, NCTC 7978, & American Type Culture Collection 49619) and Streptococcus salivarius (NCTC 8618) was assessed in vitro following treatment of approximately 10(7) c.f.u. in planktonic state with four mouthwashes.

Results: No organisms were culturable following 1-min exposure, and were not recovered following non-selective enrichment following incubation in Brain Heart Infusion broth supplemented with 0.8% (w/v) yeast extract.

Conclusions: These data indicate that such mouthwashes are able to completely kill VGS organisms tested in planktonic solution, where their use would promote good oral hygiene in patients at risk of IE.