IV. DIGESTIVE TRACT BACTERIA 1. Microbial Ecology of the Human Oral Cavity The teeth and oral epithelial surfaces are colonised by a great variety of bacte

The teeth and oral epithelial surfaces are colonised by a great variety of bacte­ rial species. A partial list of indigenous (autochthonous) organisms found in the adult human mouth is shown in Table 11 (Gibbons and van Houte, 1975; Gibbons and van Houte, 1978; Rose­ bury, 1962; Socransky and Haffajee, 1988; van Houte, 1980). Characteristi­ cally, such indigenous bacteria are well adjusted to their environment and can successfully colonise the mouth for ap­ preciable periods of time or throughout life. Their relationship with the host is neither a purely mutually beneficial one (symbiosis) nor are oral bacteria obli­ gately pathogenic (antibiosis) (Rose­ bury, 1962).