Sandwalkhttp://sandwalk.blogspot.com/2009/03/bacteria-in-your-mouth.htmlcited from: Nasidze, J. Li, D. Quinque, K. Tang, M. Stoneking (2009). Global diversity in the human salivary microbiome Genome Research DOI: 10.1101/gr.084616.108I remember because I looked specifically for the bacteria I am working with (ammonia oxidizing bacteria), and yes they were present. These are unculturable bacteria (with heterotrophic media), so they won't show up in normal culturing. There are normal commensal heterotrophic bacteria on the tongue that reduce nitrate to nitrite. That reduction only occurs in anoxic crypts of the tongue. The bacteria I am working with are aerobic and autotrophic and oxidize ammonia into nitrite. The bacteria I am working with are Nitrosomonas, Nitrosococcus, Nitrosospira at about 7:00 on the figure.