Wong Yin Wai. / Thesis submitted in: June 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 82-93). / Abstracts in English and Chinese. / Acknowledgement --- p.ii / Abstract --- p.iii / 摘要 --- p.v / Table of Content --- p.vi / List of Tables --- p.ix / List of Figures --- p.x / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Taxonomy of salmonellae --- p.1 / Chapter 1.2 --- Clinical significance --- p.2 / Chapter 1.3 --- Treatment of Salmonella infections --- p.4 / Chapter 1.4 --- Global and local prevalence of Salmonella --- p.5 / Chapter 1.5 --- Antimicrobial Susceptibilities --- p.8 / Chapter 1.5.1 --- Salmonella Typhimurium --- p.8 / Chapter 1.5.2 --- Other salmonellae --- p.9 / Chapter 1.5.3 --- Emergence of quinolone-resistant salmonellae --- p.9 / Chapter 1.6 --- Mechanisms of β-lactam resistance --- p.10 / Chapter 1.6.1 --- Enzymatic deactivation of β-lactam antibiotics --- p.10 / Chapter 1.6.2 --- Modifications of normal PBPs --- p.11 / Chapter 1.6.3 --- Alternative routes of peptidoglycan synthesis --- p.12 / Chapter 1.6.4 --- Impermeability and active efflux system --- p.12 / Chapter 1.7 --- Classification and nomenclature of β-lactamases --- p.13 / Chapter 1.7.1 --- Functional classification --- p.13 / Chapter 1.7.2 --- Molecular classification --- p.15 / Chapter 1.7.3 --- Nomenclature of β-lactamases --- p.16 / Chapter 1.8 --- β-Lactamases in salmonellae --- p.17 / Chapter 1.8.1 --- Salmonella Typhimurium --- p.17 / Chapter 1.8.2 --- Other salmonellae --- p.18 / Chapter 1.9 --- Methods for the characterization of β-lactamases --- p.18 / Chapter 1.9.1 --- Isoelectric focusing (IEF) --- p.19 / Chapter 1.9.2 --- β-Lactamase activity assays --- p.20 / Chapter 1.9.3 --- Hybridization with DNA probes --- p.20 / Chapter 1.9.4 --- Amplification of β-lactamase genes by polymerase chain reaction (PCR) --- p.21 / Chapter 1.9.5 --- Polymerase chain reaction - Single strand conformational polymorphism (PCR-SSCP) analysis --- p.23 / Chapter 1.9.6 --- Gene sequencing --- p.23 / Chapter 1.10 --- Objectives --- p.25 / Chapter 2 --- Materials and Methods --- p.26 / Chapter 2.1 --- Bacterial Strains --- p.26 / Chapter 2.1.1 --- Identification of salmonellae --- p.26 / Chapter 2.1.2 --- Antibiotics and chemicals used --- p.26 / Chapter 2.1.3 --- Antimicrobial susceptibility testing --- p.28 / Chapter 2.2 --- Localization of β-lactamase genes --- p.30 / Chapter 2.2.1 --- Transferability study --- p.30 / Chapter 2.3 --- Characterization of β-lactamases --- p.31 / Chapter 2.3.1 --- Extraction of crude β-lactamases --- p.31 / Chapter 2.3.2 --- Isoelectric focusing (IEF) --- p.31 / Chapter 2.4 --- Molecular characterization of β-lactamase genes --- p.33 / Chapter 2.4.1 --- Detection of TEM-type β-lactamase genes using polymerase chain reaction (PCR) --- p.33 / Chapter 2.4.2 --- Detection of OXA-type β-lactamase gene using PCR --- p.36 / Chapter 2.4.3 --- Detection of TEM mutations by polymerase chain reaction 一 single strand conformational polymorphism (PCR-SSCP) analysis --- p.37 / Chapter 2.4.4 --- Detection of OXA mutations by PCR-SSCP analysis --- p.38 / Chapter 2.4.5 --- Sequencing of β-lactamase genes --- p.39 / Chapter 2.4.5.1 --- Preparation of sequencing template --- p.39 / Chapter 2.4.5.2 --- Sequencing reaction --- p.39 / Chapter 2.4.5.3 --- Preparation of sequencing gel --- p.40 / Chapter 2.4.5.4 --- Silver staining of the sequencing gel --- p.41 / Chapter 2.5 --- Relatedness of ampicillin-resistant S. Typhimurium --- p.42 / Chapter 2.5.1 --- Pulsed field gel electrophoresis (PFGE) --- p.42 / Chapter 2.5.2 --- Cluster analysis --- p.44 / Chapter 3 --- Results --- p.46 / Chapter 3.1 --- Bacterial Strains --- p.46 / Chapter 3.1.1 --- Antimicrobial susceptibilities --- p.46 / Chapter 3.2 --- Characterization of β-lactamases by isoelectric focusing --- p.52 / Chapter 3.3 --- Characterization of β-lactamase genes --- p.53 / Chapter 3.3.1 --- Transferability of β-lactamase genes --- p.53 / Chapter 3.3.2 --- Detection of OXA-type β-lactamase gene by polymerase chain reaction (PCR) --- p.53 / Chapter 3.3.3 --- Detection of OXA-type mutations by polymerase chain reaction- single strand conformational polymorphism (PCR-SSCP) analysis --- p.56 / Chapter 3.3.4 --- Detection of TEM-type β-lactamase gene by PCR --- p.56 / Chapter 3.3.5 --- Detection of TEM-type mutations by PCR-SSCP analysis --- p.56 / Chapter 3.3.6 --- Sequencing of β-lactamase genes --- p.61 / Chapter 3.3.7 --- Pulsed-field gel electrophoresis --- p.64 / Chapter 4 --- Discussion --- p.67 / Chapter 4.1 --- Antimicrobial susceptibilities of S. Typhimurium in Hong Kong --- p.67 / Chapter 4.2 --- Transferability of resistance --- p.69 / Chapter 4.3 --- β-Lactamases of S. Typhimurium --- p.70 / Chapter 4.4 --- DNA sequence of β-lactamase genes --- p.72 / Chapter 4.5 --- Relatedness of ampicillin-resistant S. Typhimurium --- p.73 / Chapter 4.6 --- Methods for the characterization of β-lactamases --- p.75 / Chapter 4.7 --- Significance of this study --- p.78 / Chapter 4.8 --- Conclusions --- p.79 / Chapter 4.9 --- Further studies --- p.80 / References --- p.83