[Influence of antagonistic flora on quantity of staphylococci in the oral cavity].

The study was aimed at establishment, whether in oral cavity co-inhabit bacteria demonstrating antagonistic properties against staphylococci and whether this phenomenon may influence the size of staphylococcal population in this environment. Two locations of bacteria in oral cavity were investigated--saliva and tooth plaque. It was found that total quantity of staphylococci (both coagulase-positive and/or coagulase-negative) in saliva decreases with the age of investigated persons. Mean values amount respectively for children to 3.5 +/- 1.0 log CFU/ml and for adults to 2.9 +/- 0.7 log CFU/ml. This is statistically different (p = 0.0003). Amount of staphylococci in tooth plaques remains generally at the same level and amount to 1.4 +/- 0.6 log CFU/ml. In each tested sample of saliva and tooth plaque, presence of bacteria antagonistic to isolated from a given sample staphylococci, was detected. Among 2-4 year children and in adults, percentages of antagonistic bacteria against coagulase-positive staphylococci were higher than against coagulase-negative strains. Among children aged 5-6 and 11-13 years opposite proportions were found. Statistic analysis confirmed existence of negative correlations, both linear and ranking, between quantity of antagonistic bacteria and amounts of coagulase-positive and coagulase-negative staphylococci in the same tested samples of saliva and tooth plaque. These results suggest that antagonism between bacterial flora of oral cavity and staphylococci, is presenting one of factors limiting the quantity of staphylococci in this environment.