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''Streptococcus salivarius'' is a species of spherical, gram-positive bacteria which colonize the mouth and upper respiratory tract of humans a few hours after birth, making further exposure to the bacteria harmless in most circumstances. The bacteria is considered an opportunistic pathogen, rarely finding its way into the bloodstream, where it has been implicated in cases of sepsis in people with neutropenia,( a deficiency in white blood cells). ''S. salivarius'' has distinct characteristics when exposed to different environmental nutrients. For example, in the laboratory, if a SYTA plate (Petri dish), is used, then ''S. salivarius'' is able to use the sucrose in the SYTA plate to produce a capsule around itself. However, if grown on a GYC (glucose, yeast extract,calcium carbonate) plate, with glucose, instead of sucrose, then ''S. salivarius'' is unable to make a capsule from glucose. More importantly, in the laboratory, ''S. salivarius'' can show a distinct clearing on GYC plates. This is because ''S. salivarius'' can ferment the glucose yielding lactic acid. Next, the lactic acid actually reacts with the calcium carbonate in the GYC plate, resulting in zones of clearings on the plate.() ==Role as a probiotic== Some strains of ''S. salivarius'' are being trialed for their use as a probiotic in the prevention of oral infections. Some strains of ''S. salivarius'' are found to produce BLIS (Bacteriocin-like Inhibitory Substances) which is an antimicrobial peptide. This peptide displays interspecies inhibition, and inhibits Streptococcus pyogenes (which causes Strep throat infections). Lozenges containing S. salivarius are currently available as "K12 blis throat guard lozenges". These lozenges are marketed to support immunity against more virulent Streptococcus strains.〔http://blis.co.nz/blisk12-throatguarddaily-peppermintmint-60loz.html#.VgosNOfXenM〕 People with this strain of naturally occurring ''S. salivarius'' on their tongue have been shown to have fewer Strep throat infections.〔Wescombe, P. A., N. C. K. Heng, et al. (2009). "Streptococcal bacteriocins and the case for Streptococcus salivarius as model oral probiotics." Future Microbiology 4(7): 819-835.〕 This is also being investigated for its potential to prevent rheumatic heart disease which is also caused by ''S. pyogenes.'' Agglutination of ''Streptococcus salivarius'' is often used in the diagnosis of atypical pneumonia caused by ''Haemophilus influenzae'' 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Streptococcus salivarius」の詳細全文を読む スポンサード リンク
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