Record Details
Methods of identifying food poisoning staphylococci
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Methods of identifying food poisoning staphylococci |
| Names |
Orth, Donald Simms
(creator) Anderson, Arthur W. (advisor) |
| Date Issued | 1969-04-30 (iso8601) |
| Note | Graduation date: 1969 |
| Abstract | Several biochemical tests were studied to determine their correlation with coagulase activity. The lysozyme test was in perfect agreement with the coagulase test for the strains studied. Mannitol fermentation and egg yolk lipase tests were in agreement with the coagulase test for 96% of the coagulase positive strains. Sheep red blood cell hemolysin was produced by 90% of the Staphylococcus aureus strains, The Muller phenomenon was produced by 80% of the coagulase positive cultures. These tests were considered to be of value in determining the potential pathogenicity of staphylococci. Other biochemical tests studied did not seem to provide as good an index of food poisoning capabilities as the above tests, The DNase and phosphatase tests gave positive reactions for all strains tested, and proteolysis was shown to be variable among the different strains. These indices of pathogenicity were compared with the demonstrated ability of the various strains to produce food poisoning symptoms in experimental animals. All but one of the known enterotoxigenic Staphylococcus cultures produced food poisoning symptoms in the kitten test. A compact agar slide test system was developed for screening cultures for the presence of extracellular products. This system used concentrated cell-free supernatants in an agar substrate. In some cases, this technique was shown to be faster and more sensitive than conventional plating procedures. Some characteristics of staphylococcal coagulase were studied. It was demonstrated that S. aureus 265-1 liberated some free coagulase into the culture medium, and that some coagulase was insoluble, or associated with particulate material. Gel filtration with Sephadex G-75, pH gradient elution, and electrophoresis in polyacrylamide gels indicated that coagulase has multimolecular forms. Coagulase appears to be composed of at least two major components and a series of less active and/or prevalent components which differ in size or charge. Spectrophotometric data indicated that the coagulase preparations had UV absorption maxima near 260 nm. Coagulase activity was not necessarily correlated with protein concentration determined by %A₂₈₀ or protein staining. It is suggested that coagulase may be associated with nucleic acid material, or that it may be nucleoprotein. |
| Genre | Thesis/Dissertation |
| Topic | Staphylococcus |
| Identifier | http://hdl.handle.net/1957/46416 |
