S. aureus 1054. The recombination occurs by a novel method. The data show that pSl or pΔD contribute the site for recombination and that the gene(s) for the protein(s) involved in recombination are encoded on pOX1054 or the 1054 chromosome. Integration of the plasmids into the chromosome of 1054 was not detected.

Staphylococcus aureus protease V8 (SPV8), also known as Endoproteinase Glu-C (EC 3.4.21.19), is an enzyme isolated from the bacteria Staphylococcus aureus. This unusual enzyme has been found to cleave specifically at glutamyl and aspartyl peptide bonds and has been used as a tool in the preparation of protein substrates for amino acid sequence analysis. SPV8 has been reported to show some stability toward various denaturants (Drapeau, G.R. (1977) Methods in Enzymology_, 47:189-191). In order to more adequately assess the denaturant stability of SPV8, the effect of guanidine hydrochloride (HC1), a common protein denaturant, on the proteolytic action of SPV8 was studied. The extent of cleavage of the glutamyl peptide bond in adrenocorticotropic hormone 1-10 (ACTH 1-10) was found to decrease with increasing concentrations of guanidine HC1.At 22°C in the presence of 3.0 M guanidine HCl, only 25% of SPV8's proteolytic activity was retained. In the presence of 4.0, 5.0, or 6.0 M guanidine HC1, virtually all proteolytic activity toward the glutamyl bond of ACTH 1-10 was lost, presumably due to the inactivation of the protease by denaturation or increased autolysis mediated by the guanidine HC1. At temperatures above 22°C, SPV8 was more susceptible to inactivation by guanidine HC1. Thus SPV8 appears to retain some proteolytic activity in the presence of guanidine HC1, but only at concentrations less than 4.0 M. There was no difference in the proteolytic activity of SPV8 toward the glutamyl peptide bond of ACTH 1-10 when incubation was carried out in ammonium bicarbonate buffer (pH 7.80), phosphate buffer (pH 7.80), or Tris-HC1 buffer (pH 7.80). The presence of 1 mM calcium chloride in the 3.0 M guanidine HC1/phosphate buffer solution enhanced the enzymatic action of SPV8. The presence of 1 mM calcium chloride in Tris-HC1 buffer (pH 7.80) does not effect the proteolytic activity of SPV8 at 22°C. However, there was slight reduction in SPV8's enzymatic action toward ACTH 1-10 when the 1 mM calcium chloride was present in the 3.0 M guanidine HC1/ammonium bicarbonate buffer (pH 7.80) solution. / Department of Chemistry

Background: Staphylococcus aureus (SA) infections are common and important within the hospital environment. The case fatality rate of invasive Staphylococcus aureus (SA) infections is between 20-40%. Whether the infection is due to methicillin resistant SA (MRSA) or methicillin sensitive SA (MSSA) may determine outcomes. Literature to date is inconclusive regarding whether antimicrobial resistance in SA affects patient outcomes. Host factors, infection-host interactions, and treatment-related factors may also influence case fatality. Objectives: The purpose of this study was to determine if patients with MRSA invasive infections were more likely to die than those with MSSA invasive infections, and what factors were associated with death. Methods: A retrospective matched case control study was designed, comparing cases of MRSA with controls of MSSA invasive disease from hospitals participating in the Canadian Nosocomial Infection Surveillance Program (CNISP). Two analyses were run: the first, to identify the variables associated with MRSA vs. MSSA infections, and the second, to determine the variables associated with death in invasive Staphylococcal aureus (S. aureus) infections. Backward logistic regression analysis was used for the MRSA vs. MSSA analysis and a hierarchical logistic regression model for assessment of risk factors for death. Results: In the logistic regression MRSA model the variables: recent prior use of antibiotics, Charlson Comorbidity Index score > 2 and not having received appropriate empiric antibiotics were associated with MRSA vs. MSSA infections. The hierarchical model identified older age, higher CCI scores, immunosuppression, bloodstream infection, septic shock, neurological dysfunction and not receiving appropriate empiric antibiotic as associated with death. MRSA infection was not more likely to be associated with increased mortality than MSSA infection. Those with a resistant infection (MRSA) however, were less likely to receive appropriate empiric antibiotic treatment. Conclusions: Appropriate empiric antibiotics are the most important and only modifiable risk factor identified. Elderly patients who are on immunosuppressive drugs and have chronic comorbid conditions need to be monitored and screened more often since they are more at risk for death than others.

Background: Staphylococcus aureus (SA) infections are common and important within the hospital environment. The case fatality rate of invasive Staphylococcus aureus (SA) infections is between 20-40%. Whether the infection is due to methicillin resistant SA (MRSA) or methicillin sensitive SA (MSSA) may determine outcomes. Literature to date is inconclusive regarding whether antimicrobial resistance in SA affects patient outcomes. Host factors, infection-host interactions, and treatment-related factors may also influence case fatality. Objectives: The purpose of this study was to determine if patients with MRSA invasive infections were more likely to die than those with MSSA invasive infections, and what factors were associated with death. Methods: A retrospective matched case control study was designed, comparing cases of MRSA with controls of MSSA invasive disease from hospitals participating in the Canadian Nosocomial Infection Surveillance Program (CNISP). Two analyses were run: the first, to identify the variables associated with MRSA vs. MSSA infections, and the second, to determine the variables associated with death in invasive Staphylococcal aureus (S. aureus) infections. Backward logistic regression analysis was used for the MRSA vs. MSSA analysis and a hierarchical logistic regression model for assessment of risk factors for death. Results: In the logistic regression MRSA model the variables: recent prior use of antibiotics, Charlson Comorbidity Index score > 2 and not having received appropriate empiric antibiotics were associated with MRSA vs. MSSA infections. The hierarchical model identified older age, higher CCI scores, immunosuppression, bloodstream infection, septic shock, neurological dysfunction and not receiving appropriate empiric antibiotic as associated with death. MRSA infection was not more likely to be associated with increased mortality than MSSA infection. Those with a resistant infection (MRSA) however, were less likely to receive appropriate empiric antibiotic treatment. Conclusions: Appropriate empiric antibiotics are the most important and only modifiable risk factor identified. Elderly patients who are on immunosuppressive drugs and have chronic comorbid conditions need to be monitored and screened more often since they are more at risk for death than others.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1985. / Bibliography: leaves 119-128. / Photocopy. / Microfilm. / ix, 128 leaves, bound ill. 29 cm

Thesis (M.D.)--University of Adelaide, Faculty of Medicine, 1994. / Includes bibliographical references (leaves 152-193).

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 123-162).

Thesis (Ph. D.)--University of Missouri--Columbia, 1998. / "December 1998." Typescript. Vita. Includes bibliographical references (leaves [89]-98). Also available on the Internet.

Thèse (Ph. D.)--Université Laval, 2007. / Titre de l'écran-titre (visionné le 9 mai 2008). Bibliogr.

Zugl.: Giessen, Universiẗat, Diss., 2007.