Abstract
Comparative studies have been conducted on two separate groups of Staphylococcus strains isolated simultaneously from the saliva and infected root canals of the same individuals, with reference to their biological characteristics, pathogenicity and resistance toward antibiotics. No. 110 culture medium was used throughout the study for isolation. A total of 584 subjects being examined, 268 strains of the organisms were isolated from the saliva, 91 strains from the infected root canal, and among the total subjects only 53 yielded simultaneously from both sources a total of 123 strains. Of the 123 strains of organisms 64 deriving from the infected root canal consisted of 31 albus (25.2%), 30 aureus (24.2%) and 3 citreus (2.4%), and 33 strains deriving from the saliva comprised 33 aureus (27.0%), 22 albus (18%) and 4 citreus (3.2%) forms respectively. This indicated that predominant isolates from the root canal were albus strains and those from the saliva were aureus strains. Biological examinations on the 123 organisms revealed that 43 strains (67%) from the root canal and 46 strains (77%) from saliva fermented mannit and coagulated blood plasma while 19 strains (79%) from the root canal and 10 strains (17%) from saliva did not ferment mannit but coagulated blood plasma. There were 2 strains (3%) from the root canal and 3 strains (5%) from saliva which fermented mannit but failed to coagulate blood plasma. Virulence on mice was tested using 20 representative strains selected respectively from members of both origins, and these were injected intracutaneously on the side of the animal. The results showed that all the strains from both origins except 2 from the infected root canal developed more or less positive toxic reactions. Strains totalling to as much as 95% of the root canal origin and 98% of the saliva origin developed resistance against penicillin at the concentration more than 0.0023 unit/ml, and 45% of the former and 54% of the latter origins developed resistance against chloromycetin at the concentration more than 0.185microgram/ml, and 48% of the former and 50% of the latter origins developed resistance against streptomycin at the concentration more than 0.98/ml. It was particularly noted that resistance toward higher concentrations of the drugs was always manifested by the strains from the infected root canal rather than from saliva, and even in the experiment of double and triple exposure of these drugs, far more numder of the root canal strains exhibited higher resistance against it than the saliva strains could afford.
