Streptococcus oralis

S. oralis is one of a few pioneer species important in early colonisation of the dental pellicle, where it establishes an eubiotic biofilm believed to be protective for teeth. It discourages competition by other mouth commensals and pathobionts such as S. mutans and Candida albicans implicated in dysbiotic biofilm formation by sequestering (i.e. accumulating and storing) nutrients and releasing metabolites such as H2O2. A recent study by Leo et al. has investigated the potential mechanism employed by S. oralis to achieve biofilm establishment. MdpS also showed mild immunomodulatory activity, as the study found that it can cleave IgA to a certain extent. However, further research is required to establish these mechanisms further. == Opportunistic pathogenicity ==

S. oralis has been implicated in opportunistic cases of bacteraemia, septicaemia and meningitis in immunocompromised patients, usually in relation to chronic dental disease and/or prior treatment which could provide a point of entry. The infection most associated with S. oralis is infective endocarditis. ==Natural genetic transformation==

Like other streptococci and oral commensals, S. oralis also shows high genetic diversity. As such, it is competent for natural genetic transformation. S. oralis cells are able to take up exogenous DNA and incorporate exogenous sequence information into their genomes by homologous recombination. These bacteria can employ a predatory fratricidal mechanism for active acquisition of homologous DNA. ==References==