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Title: The Role of Cell Wall Disrupted Staphylococcus aureus in Orthopaedic infections.
Author: Page, Jonathan
ISNI:       0000 0001 3463 3998
Awarding Body: University of Newcastle Upon Tyne
Current Institution: University of Newcastle upon Tyne
Date of Award: 2003
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A large body ofwork has been done looking at the behaviour of S.aureus ATCC9144 when in the state of cell wall disruption. What had been demonstrated was an altered resistance pattern to chemotherapy. What had not been done was to investigate the behaviour ofclinically isolated S.aureus when induced into the Cell Wall Disrupted state. Through the use of clinical samples isolated from a wound bench in a district General Hospital, similar results were obtained from the clinical samples versus ATCC 9144. These included an increase in resistance to penicillin, change in growth rate and spontaneous mutation i!1 some cases to a non-MecA methicillin resistant organism. The initial method used to induce the state ofCWD required the presence of penicillin. This was felt to possibly alter the resistance of the organisms through the application ofa selective pressure. A novel media for the induction ofCWD was therefore developed and validated. Validation was through the use of: Gram Stain, Lysostaphin degradation test and Electron microscopy. The behaviour ofthe CWD organisms induced without the presence ofpenicillin was compared to those induced in the presence of penicillin. A difference was demonstrated in that the change in resistance acquired on the novel media was not a permanent change carried through in all organisms. An observational link between biofilm and CWD was noted in the laboratory. An investigation into this link looks at the adhesion abilities ofthe CWD organisms versus naive organisms. Through the use oftwo previously described adhesion tests and a novel adhesion test it was demonstrated that CWD organisms have an increased ability to adhere to surfaces. The ability to adhere is an essential mechanism needed to form biofilm, an increased ability to adhere demonstrating an increased ability to form biofilm. The possible role ofosmotic pressure and the induction ofCWD was investigated. This work demonstrated that the induction ofCWD appears to be linked to cation specific channels rather than a specific osmotic trigger as had been previously suggested. The isolation of a clinical CWD S.aureus, confirmed through gene typing demonstrated the significance ofthe research body in-vivo rather than in-vitro. CWD S.aureus demonstrates an increased resistance to cell wall active antibiotics, with an increased ability to form biofiIrn. These two mechanisms make cUnicm treatment difficult. The isolation ofa clinicalc;WO organism demoJlstrates !fiat tN~ research is relevant in-vivo.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available