マウスの口腔および腸管における S. mutans PK-1の定着性について

Conventional mice (JCL: ICR strain) were inoculated intraorally with 1.0×108 colony forming units (CFU) of S. mutans PK-1 and tested at appropriate interval for the establishment of this organism in the mouth and feces.The results obtained were as follows:1) The in vitro inhibition of indigenous microbial florae, as determined by antibiotic sensitivity disks on cultures of oral swabs and fecal samples, demonstrated that ampicillin was the most effective antibiotics in suppressing indigenous florae.2) The S. mutans PK-1 could be established in 3 samples of 10 at 3 days after, in 9 samples of 10 at 14 and 28 days after and in all samples of 10 at 56 days after in the oral swabs of experimental group that had received ampicillin to supress indigenous florae. While, in the oral swabs of controll groups, the S. mutans PK-1 could not be established in 7 samples of 10 at 3 and 14 days after. But, the difference in two groups at 56 days after could not be found.3) The amount of microorganisms at 28 days after in the oral swabs of experimental groups was statistically higer than the amount in control groups.