Some strains of coagulase-negative staphylococci produce an extracellular material, slime, which mediates adherence to foreign surfaces, such as indwelling biomedical devices. It is not known if slime is involved in adherence to human tissue. Coagulase-negative staphylococci are the most common members of normal ocular flora and cause many ocular infections, although the role of slime in these infections has not been studied.

Gram-positive pathogens are responsible for a wide range of global diseases, including nosocomial infections. The increasing incidence of antibiotic-resistant strains warrants the development of novel therapeutic strategies to combat these organisms.

Call number: LD2668 .T4 1959 P36

Doctor of Philosophy / This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au

Doctor of Philosophy / This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au

Thesis (doctoral)--Uppsala University, 1981. / Bibliography: p. 28-37.

Bacterial superantigens (SAgs) are virulence factors that induce nonspecific T-cell proliferation contributing to host immune avoidance, and occasionally severe life-threatening toxinoses such as toxic shock syndrome. In the current study, the multiple functions of 3 superantigens named staphylococcal enterotoxin-like toxins X, Y and Z are investigated. SElX and SElZ were non-emetic in a musk shrew model of emesis. SElX is structurally and phylogenetically related to staphylococcal superantigen-like proteins (SSls) which are non-mitogenic but exhibit a variety of immune modulatory properties. We carried out protein and gene expression analysis of mutants of different S. aureus gene regulators and demonstrated that selx expression is controlled by saeRS, a two-component regulator linked to the bacterial response to phagocytic signals. Considering the co-regulation of SElX with known mediators of innate immune evasion we investigated a potential role for SElX in both humoral and cellular innate immune modulation and discovered that SElX strongly binds to human, bovine, murine, and laprine neutrophils and interferes with IgG-mediated phagocytosis, independently of Fcγ receptor signalling. Bacterial survival assays with neutrophils demonstrated that the deletion of selx significantly reduced the ability of S. aureus to resist neutrophil killing. Site-directed mutagenesis in the conserved sialic acid-binding motif of SElX abolished its neutrophil binding capacity, which is consistent with a critical role for glycosylated receptors in this interaction. Importantly, the sialic-acid binding mutants of SElX retained the ability to induce T-cell proliferation demonstrating that the distinct functions of SElX are mechanistically independent. Affinity precipitation experiments identified potential glycoprotein receptors for SElX and the interaction with protein ICAM-3, an important ligand for MAC-1 integrins, was validated suggesting SElX may interfere with cell signalling. Taken together, we present the first example of a bi-functional SAg that can manipulate two distinct arms of the human immune system and contribute to S. aureus survival during infection.

Attempts were made to adapt the microtiter hemagglutination inhibition assay technique for the assay of enterotoxin A. The presence of a potent hemagglutinin in crude and partially purified preparations and the instability of sensitized erythrocytes prevented its use for routine analysis of enterotoxin from culture media and foods. A capillary tube immunological assay was developed in which 1 μ g of enterotoxin/ml was detected in less than 1 hr . Interfacial reaction of antisera and enterotoxin solutions in a 1 mm internal diameter capillary tube allowed rapid detection and serological typing of enterotoxins. Staphylococcus aureus growth and enterotoxin A development in Cheddar cheese slurry was evaluated. S. aureus growth and enterotoxin production occurred at 32 C. in 45 and 60% moisture cheese slurries following inoculation with 10 3 to 10 5 bacteria/gram. Hydrogen peroxide (0. 5%) treatment of slurry at 37 C did not inhibit S. aureus and enterotoxin A development. Heating slurry at 72 C for 30 min eliminated staphylococci but reinoculation with ripening organisms was essential. Addition of sorbic acid (0. 2 to 0. 3%) to a slurry adjusted to pH 5. 0 with lactic acid, inhibited staphylococci. in milk and slurry. Cheese flavor development was retarded due to inhibition of micrococci and lipolysis. Non-protein nitrogen increases paralleled that of sorbate-free controls. Sorbate treatment was preferred over other treatments .

No description available.

Chio Weng Fan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 131-149). / Abstracts in English and Chinese. / Acknowledgments --- p.i / Abstract --- p.ii / Contents --- p.iv / List of tables --- p.ix / List of figures --- p.x / List of abbreviation --- p.xii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Biology of Staphylococci --- p.1 / Chapter 1.1.1 --- Taxonomy --- p.1 / Chapter 1.1.2 --- Characteristics of S. aureus --- p.2 / Chapter 1.2 --- Methicillin-resistant Staphylococcus aureus --- p.1 / Chapter 1.2.1 --- Description of MRSA --- p.7 / Chapter 1.2.2 --- Antibiotic Resistance of MRSA --- p.7 / Chapter 1.2.2.1 --- Resistance to β-lactam Antibiotics --- p.8 / Chapter 1.2.2.1.1 --- Production of β-lactamase --- p.8 / Chapter 1.2.2.1.2 --- Penicillin-binding Protein PBP2a --- p.8 / Chapter 1.2.2.1.3 --- Borderline Methicillin Resistance --- p.11 / Chapter 1.2.2.2 --- Resistance to Antibiotics other than β-lactams --- p.11 / Chapter 1.2.3 --- Epidemiology of MRSA --- p.15 / Chapter 1.2.3.1 --- Clinical Significance of MRSA --- p.15 / Chapter 1.2.3.1.1 --- Evolution of MRSA --- p.16 / Chapter 1.2.3.1.2 --- Epidemiology of MRSA Worldwide --- p.17 / Chapter 1.2.3.2 --- MRSA in Hong Kong --- p.21 / Chapter 1.3 --- Strain Typing for MRSA --- p.26 / Chapter 1.3.1 --- Phenotypic Methods --- p.27 / Chapter 1.3.1.1 --- Antibiotic Susceptibility Test --- p.27 / Chapter 1.3.1.2 --- Bacteriophage Typing --- p.28 / Chapter 1.3.1.3 --- Multilocus Enzyme Electrophoresis --- p.29 / Chapter 1.3.2 --- Genotypic Methods --- p.30 / Chapter 1.3.2.1 --- Analysis of Chromosomal DNA --- p.30 / Chapter 1.3.2.1.1 --- Pulsed-field Gel Electrophoresis (PFGE) --- p.30 / Chapter 1.3.2.1.2 --- Amplified Fragment Length Polymorphism (AFLP) --- p.31 / Chapter 1.3.2.2 --- Analysis of Gene Polymorphism --- p.32 / Chapter 1.3.2.2.1 --- PCR-Restriction Length Polymorphism (PCR-RFLP) --- p.32 / Chapter 1.3.2.2.2 --- Random Amplification of Polymorphic DNA (RAPD) --- p.33 / Chapter 1.3.2.2.3 --- Nucleotide Sequence Typing --- p.33 / Chapter 1.3.2.2.3.1 --- A Typing --- p.33 / Chapter 1.3.2.2.3.2 --- Multilocus Sequence Typing --- p.33 / Chapter 1.3.2.3 --- Hybridization by Southern Blotting --- p.34 / Chapter 1.3.2.3.1 --- MecA/Tn544 Probe Typing --- p.34 / Chapter 1.3.2.3.2 --- Binary Typing --- p.34 / Chapter 1.3.2.4 --- Analysis of Plasmid DNA --- p.35 / Chapter 1.4 --- Objectives of the Project --- p.37 / Chapter Chapter 2 --- Materials & Methods --- p.38 / Chapter 2.1 --- Bacterial Isolates & Culture Conditions --- p.38 / Chapter 2.1.1 --- Study Period & Sample Sources --- p.38 / Chapter 2.1.2 --- Selection of Bacterial Isolates --- p.38 / Chapter 2.1.3 --- Reference Strains --- p.38 / Chapter 2.1.4 --- Culture & Storage Conditions --- p.39 / Chapter 2.1.5 --- Identification of MRSA --- p.39 / Chapter 2.2 --- Antibiotic Susceptibility Testing --- p.40 / Chapter 2.3 --- PCR for MecA Gene --- p.43 / Chapter 2.3.1 --- DNA Preparation and Primer Design for mecA Gene --- p.43 / Chapter 2.3.2 --- PCR Amplification of mecA Gene --- p.45 / Chapter 2.3.2.1 --- Master Mix Preparation --- p.45 / Chapter 2.3.2.2 --- Polymerase Chain Reaction --- p.45 / Chapter 2.3.2.3 --- Analysis of PCR Products by Agarose Gel Electrophoresis --- p.45 / Chapter 2.3.2.4 --- Precautions to Avoid Cross-contamination --- p.46 / Chapter 2.4 --- Pulsed-field Gel Electrophoresis (PFGE) --- p.47 / Chapter 2.4.1 --- PFGE Protocol --- p.47 / Chapter 2.4.1.1 --- DNA Preparation for PFGE --- p.47 / Chapter 2.4.1.2 --- Restriction Enzyme Digestion --- p.48 / Chapter 2.4.1.3 --- Pulsed-field Gel Electrophoresis --- p.48 / Chapter 2.4.1.4 --- Standards & Markers for PFGE --- p.48 / Chapter 2.4.2 --- Optimization of PFGE --- p.49 / Chapter 2.4.3 --- Computer Analysis of PFGE Patterns --- p.49 / Chapter 2.5 --- Amplified Fragment Length Polymorphism (AFLP) --- p.52 / Chapter 2.5.1 --- Amplified Fragment Length Polymorphism Protocol --- p.52 / Chapter 2.5.1.1 --- DNA Preparation --- p.52 / Chapter 2.5.1.2 --- Enzyme Digestion & Ligation --- p.53 / Chapter 2.5.1.3 --- PCR for AFLP --- p.53 / Chapter 2.5.1.4 --- Gel Electrophoresis for AFLP --- p.54 / Chapter 2.5.1.5 --- Standards & Markers for AFLP --- p.55 / Chapter 2.5.2 --- Computer Analysis for AFLP Patterns --- p.55 / Chapter 2.6 --- Phage Typing --- p.58 / Chapter 2.6.1 --- Phages & Propagating Strains --- p.58 / Chapter 2.6.2 --- Phage Typing Protocol --- p.58 / Chapter 2.6.3 --- Data Analysis and Results Interpretation for Phage Tying --- p.62 / Chapter 2.7 --- Other Typing Methods --- p.63 / Chapter 2.7.1 --- PCR Restriction Fragment Length Polymorphism for the coa gene --- p.63 / Chapter 2.7.1.1 --- Primer Design --- p.63 / Chapter 2.7.1.2 --- DNA Preparation --- p.63 / Chapter 2.7.1.3 --- Optimization of PCR --- p.63 / Chapter 2.7.1.3.1 --- PCR Amplification --- p.64 / Chapter 2.7.1.3.2 --- Restriction Enzyme Digestion --- p.64 / Chapter 2.7.2 --- Multilocus Sequence Typing --- p.64 / Chapter 2.7.2.1 --- Preparation of Chromosomal DNA --- p.65 / Chapter 2.7.2.2 --- PCR for MLST Gene --- p.65 / Chapter 2.7.2.3 --- Purification of DNA for Sequencing --- p.67 / Chapter 2.7.2.4 --- PCR for Sequencing --- p.67 / Chapter 2.7.2.5 --- Sequencing by Automatic DNA Analyzer & Data Analysis --- p.68 / Chapter Chapter 3 --- Results --- p.69 / Chapter 3.1 --- Bacterial Isolates --- p.69 / Chapter 3.2 --- Antibiotic Susceptibility Testing --- p.72 / Chapter 3.3 --- PCR for MecA Gene --- p.78 / Chapter 3.4 --- Pulsed-field Gel Electrophoresis --- p.80 / Chapter 3.4.1 --- Optimization of PFGE --- p.80 / Chapter 3.4.2 --- Analysis of PFGE Profiles --- p.83 / Chapter 3.5 --- Amplified Fragment Length Polymorphism --- p.95 / Chapter 3.6 --- Phage Typing --- p.102 / Chapter 3.7 --- Other Typing Methods --- p.109 / Chapter 3.7.1 --- PCR Restriction Fragment Length Polymorphism for the Coa Gene --- p.109 / Chapter 3.7.1.1 --- Optimization of PCR conditions for the Coa Gene --- p.109 / Chapter 3.7.1.2 --- Analysis of MRSA by PCR-RFLP of the coa Gene --- p.109 / Chapter 3.7.2 --- Multilocus Sequence Typing --- p.115 / Chapter Chapter 4 --- Discussion --- p.116 / Chapter 4.1 --- Evaluation of Typing methods for MRSA --- p.116 / Chapter 4.1.1 --- Antibiotic Susceptibility Testing --- p.116 / Chapter 4.1.2 --- Phage Typing --- p.117 / Chapter 4.1.3 --- Pulsed-field Gel Electrophoresis --- p.118 / Chapter 4.1.4 --- Amplified Fragment Length Polymorphism --- p.119 / Chapter 4.1.5 --- PCR-Restriction Fragment Length Polymorphism for the Coa Gene --- p.120 / Chapter 4.1.6 --- Multilocus Sequence Typing --- p.121 / Chapter 4.1.7 --- Conclusion for Method Evaluation --- p.122 / Chapter 4.2 --- "Analysis of Results of Antibiotic Susceptibility Test, Phage Typing, PFGE, AFLP, PCR-RFLP (Coa) & MLST" --- p.124 / Chapter 4.2.1 --- Correlation between Methods --- p.124 / Chapter 4.2.2 --- Clinical Correlation --- p.125 / Chapter 4.2.3 --- Correlation between MRSA Isolates at PWH and Reference Strains --- p.128 / Chapter 4.3 --- Future Research --- p.129 / Chapter 4.4 --- Conclusion --- p.130 / Reference List --- p.131 / Appendix I Reagent & Material Lists for Methods --- p.150 / Appendix II Buffers & Media --- p.156 / Appendix III Coa Gene Sequences of Isolates from PWH and Reference Strains --- p.158 / Appendix IV Unique antibiotic resistance profiles --- p.165 / "Appendix V Details of MRSA iolates selected for AFLP, Phage typing and MLST" --- p.166