Identification of Nitrate Reducing Bacteria from the Oral Cavity of Rats and Pigs

摘要

Within the oral cavity most nitrate reduction was detected on the dorsal surface of the tongue. Nitrite producing bacteria (NPB) were isolated from tongues of pigs obtained from a local abattoir and compared with previous results from laboratory rats (10). The most commonly isolated genus was Staphylococcus in both pig and rat with Staphylococcus sciuri being the most common species. Other nitrate reducing bacteria included Enterobacteriaciae, Micrococcus, Streptococcus and Pasteurella spp. in the pig and Pasteurella and Streptococcus spp. in the rat. Nitrate reduction and numbers of nitrate reducing bacteria were very similar over the surface of tongues from pigs. Conversely, in the rat the enumeration of culturable bacteria (cfu) showed an increase in the density of bacteria towards the posterior tongue. The proportion of culturable NPB in the total bacterial population increased from 6 percent on the anterior tongue to 65 percent on the posterior tongue. Nitrite production was sensitive to oxygen and significant nitrite generation was only detected on the posterior tongue of rats where the majority of bacteria are situated in deep clefts in the tongue surface. In the pig, deep clefts were found over the entire tongue surface.