Interactions within a collection of eight bacterial stains isolated from a monkey dental root canal

Eight bacterial strains belonging to 6 genera, 2 facultatively anaerobic and 6 obligately anaerobic species, isolated from an autogenously infected dental root canal in a monkey, were used for in vivo and in vitro interference studies. In the tissue cage studies Bacteroides oralis, Fusobaclerium necrophorum, Peptostreptococcus anaerobius and Streptococcus milleri dominated at the end of the experiment. They induced high liters of circulating antibodies in the rabbits. This result was in concordance with the development of a mixed infection in the dental apical region model in monkeys as revealed in previous experiments. In the test tube studies Streptococcus faecalis (Enterococcusfaecalis) , a rapidly growing facultatively anaerobic bacterial species, overgrew and survived the tested anaerobes. On agar plates S. milleri was negatively influenced by 3 anaerobic species and S. faecalis . Factors interacting in vitro seemed to play a minor role in vivo . It appears that the tissue cage model offers a valuable in vivo model for studies of mixed anaerobic infections in terms of bacterial interference.