Biochemical properties of virulent and avirulent staphylococci

PURIFICATION OF STAPHYLOCOCCAL BETA-HEMOLYSIN AND ITS ACTION ON STAPHYLOCOCCAL AND STREPTOCOCCAL CELL WALLS

Chesbro, William R. (University of New Hampshire, Durham), Fred P. Heydrick, Roland Martineau, and Gail N. Perkins. Purification of staphylococcal beta-hemolysin and its action on staphylococcal and streptococcal cell walls. J. Bacteriol. 89:378-389. 1965.-After growth of bovine-derived strains of Staphylococcus aureus in a completely dialyzable medium, the beta-hemolysin in the culture supernatant fluids was purified by gradient-elution chromatography on cellulose phosphate. The purified hemolysin contained two components, demonstrable by immunodiffusion or electrophoresis, but was free from alpha-hemolysin, coagulase, Delta-hemolysin, enterotoxins A and B, glucuronidase, hyaluronidase, lipase, muramidase, Panton-Valentine leukocidin, phosphatase, and protease. The hemolysin was heat-labile and sulfhydryl-dependent, and the preparation was leukocidal for guinea pig macrophages. When rabbit red blood cell (RBC) stroma and staphylococcal or enterococcal cell walls were treated with the purified hemolysin, it liberated mucopolysaccharides from the rabbit RBC stroma, polysaccharides and mucopolysaccharides (or mucopeptides) from the staphyloccoal cell walls, and rhamnose, glucose, an unidentified monosaccharide, N-acetylglucosamine, and at least two polysaccharides from the enterococcal cell walls. The hemolytic and cell-wall degradative activities had similar thermal inactivation kinetics, pH optima, sedimentation coefficients, and chromatographic and electrophoretic mobilities; both required Mg and were inhibited by thiol-inactivating agents. Consequently, it seems likely that both activities are expressions of the same enzyme.

CHARACTERISTICS OF A STRAIN OF STAPHYLOCOCCUS AUREUS GROWN IN VIVO AND IN VITRO

Beining, Paul R. (The Catholic University of America, Washington, D.C.) and E. R. Kennedy. Characteristics of a strain of Staphylococcus aureus grown in vivo and in vitro. J. Bacteriol. 85:732-741. 1963.-A comparative survey was conducted on the characteristics of a strain of Staphylococcus aureus after it had been grown in vitro (VSB) and after it had been collected from the peritoneal exudate of an infected guinea pig (GSB). Both VSB and GSB strains gave the same results when studied in an extensive series of tests, including bound and soluble coagulases, bacteriophage type, antibiotic-sensitivity pattern, the usual fermentation reactions, deoxyribonucleic acid base composition, and qualitative tests for hemolysins, deoxyribonuclease, ribonuclease, staphylokinase, staphyloprotease, lipase, and phosphatase. The in vivo strain differed significantly from the in vitro strain in respiratory rate, agar gel diffusion studies, agglutinability in tube tests, virulence tests in rabbits and mice, growth on tellurite-glycine agar, susceptibility to human gamma-globulin in agar, and in the quantitative production of deoxyribonuclease, alpha-hemolysin, leucocidin, and hyaluronidase.

The hemolysins of Staphylococcus aureus

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Surface-bound nuclease of Staphylococcus aureus: localization of the enzyme

The cellular localization of staphylococcus nuclease, previously known as an exoenzyme, was investigated, and the following results were obtained. (i) When Staphylococcus aureus cells were converted to protoplasts by cell wall lytic enzyme L-11 (a bacteriolytic enzyme purified from Flavobacterium sp. which specifically hydrolyzes amide and peptide linkages of murein layers), over 80% of the cell-bound nuclease was released into the surrounding sucrose medium. (ii) The cell-bound nuclease was associated with the cell-wall membrane fraction of mechanically disrupted cells. (iii) The nuclease activity of cell-wall membrane fractions from cells during early and late stages of protoplast formation were compared. Less activity was found in the late stage. These results suggest that nuclease may be located at or near the surface of the cells. The distribution of cell-bound nuclease in the cell-wall membrane fraction varied with the growth conditions of S. aureus. The activity of alkaline phosphatase, another surface enzyme, was also investigated. Less of this enzyme than nuclease was released when the cells were converted to protoplasts.

Beta hemolysin: a persistent impurity in preparations of staphylococcal nuclease and enterotoxin

Purified staphylococcal nuclease and enterotoxin B from several sources contained beta hemolysin whose physicochemical resemblances to the other two proteins make its elimination difficult.

Identification of staphylococci isolated from clinical material

A total of 350 staphylococci isolated from various clinical sources were examined for bound and free coagulase, fermentation of mannitol, and deoxyribonuclease. The economical coagulase-mannitol-agar method of Esber and Faulcomer was found to be suitable for the detection of free coagulase and mannitol fermentation. A significant number of coagulase- and mannitol-negative staphylococci proved to be deoxyribonuclease-positive.

Enzymatic detection of the growth of Staphylococcus aureus in foods

A specific method has been developed for the extraction and measurement of staphylococcal nuclease in foods in which Staphylococcus aureus has grown. The method was used to compare staphylococcal growth with nuclease production in foods under varying conditions of temperature, aerobiosis, and competition from other microorganisms. It was concluded that the nuclease is produced under any conditions that permit growth of S. aureus, and little or no interference with the test was encountered either from mixed, natural populations or from a variety of pure, laboratory cultures. Nuclease and enterotoxin A production were shown to vary in synchrony for the 234 (Casman) strain of S. aureus, and the sensitivity of the enzymatic detection of nuclease was comparable to the sensitivity of serological detection of enterotoxin A. It was found that 15 min at 121 C was required to reduce the nuclease activity in slurries of contaminated ham below the level present in the unheated slurry. The extraordinary heat resistance of the nuclease permits its detection even in foods heated subsequent to the growth of S. aureus. The nuclease analysis requires about 3 hr to complete and requires no unusual equipment or reagents.

Egg Yolk Factor of Staphylococcus aureus II. Characterization of the Lipase Activity

Shah , D. B. (University of Wisconsin, Madison), and J. B. Wilson . Egg yolk factor of Staphylococcus aureus . II. Characterization of the lipase activity. J. Bacteriol. 89: 949–953. 1965.—The staphylococcal egg yolk factor was characterized as a lipase. The enzyme had an optimal p H of 7.8, but the optimal p H of stability was 7. Substrate specificity data showed that the relative rate of hydrolysis was lowest with triacetin as substrate, was maximal with tributyrin, and decreased as the chain length of the acyl moieties increased. The enzyme showed an absolute requirement for a fatty acid acceptor like calcium, when the acyl moiety of triglyceride was water-insoluble. Magnesium, strontium, and barium functioned equally well as fatty acid acceptors. The enzyme was able to hydrolyze coconut oil, peanut oil, olive oil, and egg yolk oil.

CORRELATION BETWEEN ACID PHOSPHATASE AND COAGULASE PRODUCTION OR PHAGE TYPE OF STAPHYLOCOCCUS AUREUS

Pan, Yue-Liang (University of Michigan Medical School, Ann Arbor), and Harold J. Blumenthal . Correlation between acid phosphatase and coagulase production or phage type of Staphylococcus aureus . J. Bacteriol. 82: 124–129. 1961.—A quantitative assay of acid phosphatase in 26 coagulase-negative and 73 coagulase-positive strains of Staphylococcus aureus was performed using an assay procedure modified to estimate extracellular, as well as the cellular, phosphatase. Some of the factors affecting the formation of acid phosphatase were studied. On the average, coagulase-negative strains produced 4.0 units and coagulase-positive strains 19.6 units although some negative strains produced more phosphatase than positive strains. More phosphatase was produced by strains of phage-group I than by strains of any other group.