Streptococcus gordonii is a Gram-positivebacterium included among some of the initial colonizers of the periodontal environment.[1] The organism, along with related oral streptococci, has a high affinity for molecules in the salivary pellicle (or coating) on tooth surfaces. S. gordonii therefore can rapidly colonize clean tooth surfaces, and S. gordonii along with related organisms comprise a high percentage, up to 70%, of the bacterial biofilm that forms on clean tooth surfaces. Generally harmless in the mouth, S. gordonii can cause acute bacterial endocarditis upon gaining access systemically. S. gordonii also forms an attachment substratum for later colonizers of tooth surface and can modulate the pathogenicity of these secondary colonizers through interspecies communication mechanisms.[citation needed]
Upon systemic infection, S. gordonii is subjected to conditions in human blood that damage its DNA. However, DNA damage can be tolerated by the use of DNA repair processes.[3] The S. gordonii genome encodes a two protein complex, RexAB, that is employed in recombinational repair and can promote survival by repairing DNA double-strand breaks.[3]
References
^American Academy of Periodontology 2010 In-Service Exam, question 82
