1991 Volume 54 Issue 3 Pages 180-198
We attempted to gain information about the genetic basis of the pathogenicity of Bacteroides gingivalis.
Of 56 clinical isolates, 11 strains released bacteriophages of similar morphology when irradiated with ultraviolet light. The majority of bacteriophages had a hexagonal head 50 to 67nm in diameter with a long flexible tail of 200 to 267nm. A 5.7 kilobase plasmid was detected in two of the 56 strains by the use of agarose gel. Almost all strains produced trypsin, acid and alkaline phosphatase, collagenase, plasmin, and DNase, but no strains produced lecithinase or β-lactamase. As revealed by negative staining, all strains examined possessed surface appendages on and vesicles around the cell surface. Two morphologically distinct types of surface appendages, designated Type A and B, were observed. Type A appendages had extremely thin filaments with diameters of 5nm. Type B appendages, which were 10nm in diameter, were associated exclusively with strain 10013.
No correlation was found between lysogenicity and phenotypic characteristics. However, two strains carrying a plasmid were resistant to β-lactam antibiotics.
