Distribution ofStreptococcus milleriin the Oral Cavities of Japanese Children

Distribution and characterization of hemolytic activity by an oral anaerobe from the Streptococcus milleri group

Some oral anaerobes from the Streptococcus milleri strain group were found to secrete human specific hemolytic toxin, which was detected when bacteria were cultured in Todd-Hewitt broth and Brain Heart Infusion broth. The toxin elicited by the Streptococcus intermedius strain was partially fractionated by ammonium sulfate precipitation. Preincubation with glutathione or cysteine showed significant inhibiting effects; however, no effects were seen with dithiothreitol or beta-mercaptoethanol, and cholesterol was a weak inhibitor. Five kinds of protease inhibitor had no effect on the hemolytic activity, and rabbit preimmune and immune sera against the bacterial cells showed weak inhibition at a similar level. Digestion with trypsin, chymotrypsin, proteinase-K, subtilisin and pronase-P brought about a rise in activity, followed by a decrease during long-term incubation. Other enzymes tested showed no effects. Further, the presence of the intermedilysin gene in the portion with hemolytic activity was not identified by polymerase chain reaction.

Isolation and properties of bacteriolytic enzyme-producing cocci from the human mouth

One-hundred-and-one bacteriolytic enzyme producing organisms were isolated from various sites of the mouth. All were non-hemolytic, Gram-positive, and chain-forming cocci. Ninety-one strains, like the reference strains of Streptococcus defectivus and S. adjacens, were dependent on pyridoxal for growth and produced a chromophore. The Rapid ID32 STREP system speciated these isolates as S. defectivus, S. adjacens or Gemella morbillorum. The remaining 10 bacteriolytic isolates were pyridoxal-independent and 8 belonged to S. intermediate. Some pyridoxal-independent S. intermedius reference strains including ATCC27335T and all group D Enterococcus strains tested were also bacteriolytic. Thus, bacteriolytic enzyme production is common to nutritionally variant streptococci but not unique to S. defectives and S. adjacens. The nutritionally variant strains generally had arylamidases but not alkaline phosphatase. The S. defectivus strains produced alpha-and beta-galactosidases (biotype 1) whereas the S. adjacens strains generally produced N-acetyl-beta-glucosaminidase and some had beta-glucuronidase but others did not (biotypes 2 and 3). The C. morbillorum strains had no detectable activity of these glycosidases (biotype 4) but produced a chromophore and an arginine dihydrolase, exhibiting a physiological profile atypical of the Gemella species. This indicates the possible presence of an additional phenotypic group or a new species among the nutritionally variant streptococci.

Immunochemical characterization of the carbohydrate antigens of serotype k and Lancefield group G "Streptococcus milleri"

Carbohydrate antigens of the serotype k/Lancefield group G "Streptococcus milleri" were extracted by autoclaving whole cells of the type k reference strain Streptococcus anginosus K214-2K. The type k and group G antigen molecules are separated from each other and partially purified by a DEAE-Sephadex A25 column chromatography followed by a Sephadex G-100 gel filtration. In the double diffusion and the immunoelectrophoresis, the type k and group G antigen preparations obtained yielded single bands with their homologous antisera respectively. The type k antigen preparation contained principally glycerol, rhamnose, ribitol, galactose and glucose in a molar ratio of 0.54:1.20:0.43:0.33:1.00. The quantitative precipitin inhibition test indicated that beta(1-6)glucosyl-glucose (gentiobiose) sequence played a major role in immunodeterminant structure. Thus, the type k antigen of "S. milleri" appears to be a new carbohydrate type antigen that is chemically different from any Ottens type antigen. In contrast, the group G antigen preparation contained high proportion of rhamnose in addition to glucose, N-acetylglucosamine and N-acetylgalactosamine in a molar ratio of 6.45:1.00:0.24:1.15, and the rhamnose residue was involved in the immunodominant epitope, being in good agreement with the previously proposed chemical structure of the group antigen.

Immunochemical characterization of the carbohydrate antigens of serotype c/Lancefield group C "Streptococcus milleri"

Carbohydrate antigens of the serotype c/Lancefield group C "Streptococcus milleri" were extracted by autoclaving whole cells of the type c reference strain K51Y. The type c and group C antigen molecules were separated and partially purified by a DEAE-Sephadex A-25 column chromatography followed by Sephadex G-100 gel filtration. The purified type c antigen and group C antigen were homogeneous in the double diffusion and in the immunoelectrophoresis. The type c antigen was composed principally of glycerol, rhamnose, glucose and N-acetylglucosamine in a molar ratio of 0.22:0.27:1.00:0.48. The quantitative precipitin inhibition test indicated that N-acetylglucosamine played a major role in immunodeterminant structure. Thus, the type c antigen of "S. milleri" is a new carbohydrate type antigen and is immunochemically different from the Ottens-type antigen III found occasionally in group C streptococci. In contrast, the group C antigen preparation contained a high proportion of N-acetylgalactosamine in addition to glycerol, rhamnose, glucose and N-acetylglucosamine, and the N-acetylgalactosamine residue was involved in the immunodominant epitope, being in good agreement with the previously proposed chemical structure of the group antigen. N-acetylgalactosamine was detected in the autoclaved extracts of a nontypeable/group C strain but not of a type c/ungroupable strain.

Carbohydrate antigen of serotype g "Streptococcus milleri": immunochemical characterization

Cell wall carbohydrate antigen of the serotype g "Streptococcus milleri" was extracted with cold trichloroacetic acid from purified cell walls of the type strain K1K. The extracts were then purified by a DEAE-Sephadex A-25 column, followed by a Sephadex G-100 column. The immunoelectrophoresis revealed that the serotype g carbohydrate antigen preparation displayed a single precipitin band against the crude anti-K1K serum. The purified type g antigen consisted of rhamnose, galactose, glucose and galactosamine in a ratio of 1.3:3.8:1.0:2.5. The quantitative precipitin inhibition test with various haptens indicated that galactosamine is a major immunodeterminant of the type g-specific antigen.