Masaru Suganuma

Platelet Aggregation by Strains of Enterococci

The platelet aggregation capability of whole cells of Enterococcus faecalis, E. faecium and E. avium was tested. The optimum ratios of bacteria to platelets in E. faecalis (strain SMU‐37), E. faecium (strain SMU‐138) and E. avium (strain SMU‐197) were 1.0, 1.2 and 2.0, respectively. During the platelet aggregation induced by the three strains of enterococci, 65–69% of total serotonin was released. The aggregation was totally inhibited by ethylenediaminetetraacetate (10 mM) and apyrase (1 mg/ml), while no effect was shown by aspirin (10 mM), indomethacin (10 mM) and quinacrine (1 mM). By pretreatment of platelet‐poor plasma with heat (56 C, 30 min) or zymosan, the reactivities with platelets of each strain of species were markedly diminished. These results suggest that enterococci‐induced platelet aggregation was an ion‐dependent, cyclooxygenase‐insensitive event, and plasma component(s) was (were) required for the reaction.

Platelet Aggregation Induced by Strains of Various Species of Coagulase-Negative Staphylococci

Major species of coagulase‐negative staphylococci (CNS) were tested for their ability to induce platelet aggregation in rabbit platelet‐rich plasma (PRP). Among 11 species of CNS tested, a majority of the strains of 10 species of CNS (S. epidermidis, S. simulans, S. capitis, S. hyicus, S. sciuri, S. cohnii, S. xylosus, S. hominis, S. haemolyticus, S. warneri) caused induction of the platelet aggregation and serotonin release, while S. saprophyticus did not show such activity. The addition of aspirin (10 mM) or quinacrine (1 mM) to PRP resulted in no remarkable effect on the platelet aggregation induced by these strains and it was shown that the platelet aggregation did not require arachidonate pathways. Complement system components were shown to be one of the plasma factors required for platelet aggregation by ten strains of each species of CNS. The bacterial substance participating in the platelet aggregation by ten species of CNS tested was indicated to be heat‐stable and trypsin‐resistant, while the activity of a strain of S. epidermidis was susceptible to trypsin.

Immunochemical Characterization and Biological Properties of a Cell Surface Antigen Extracted from Encapsulated Staphylococcus epidermidis Strain SE-l0

Protection inducing antigen (PIA) was mechanically extracted from Staphylococcus epidermidis (encapsulated strain SE-10) and purified by DEAE-Sephadex A 25 (C1- form) ion exchange chromatography. Major carbohydrate constituents of PIA were galactose, glucose, and N-acetylglucosamine at the molar ratio 1.00:0.96:0.78. Antigenic activity was considerably reduced after sodium metaperiodate oxidation, however, pronase digestion was not effective. N-acetylglucosamine residues were shown to be closely related to the antigenic determinant. No cross reactivity to PIAs from other encapsulated strains of S. epidermidis was found which indicates type specificity. Protection of mice after immunization and enhancement of human granulocyte function suggests that PIA might be considered to be a biological response modifying substance.

Isolation of a Serologically Different Compact‐Colony‐Forming Active Substance from Strains of Staphylococcus aureus

To observe the possible serological heterogeneity of compact‐colony‐forming active substance (CCFAS), heat‐killed vaccines were prepared by two strains of Staphylococcus aureus, strains SMU 1–46 and SMU 7931, cultured in 0.03 M tris‐hydrochloride‐buffered brain heart infusion, pH 8.4. After immunization with the vaccine in rabbits, antibody responses were observed during a period of six weeks after the immunization either by homologous and heterologous organisms using alkaline serum‐soft agar technique. The results showed that remarkable antibody production was shown only against homologous strain, but not against heterologous strain. The antibodies were absorbed out only with highly purified preparation of CCFAS extracted from homologous strain and not with heterologous CCFAS. Differences of the major chemical composition of the substances showed that highly purified CCFAS extracted from strain SMU 7931 contained 2.84 and 2.04 times higher amounts of galactose and 2‐amino‐2‐deoxy‐D‐galacturonic acid than those of CCFAS obtained from strain SMU 1–46.