Microbiology Commons^™

Validation Of An Immunomagnetic-Electrochemiluminescence Detection System For The Detection Of Escherichia Coli 0157 In Food And Comparison With An Iso Standard Method, Eimear Carney

Theses

Rapid and sensitive methods for detecting Escherichia coli 0157 in contaminated food, water and other biological samples are important in limiting and preventing the spread of this pathogen. Traditional culture based methods for bacterial identification and detection can be time consuming and labour intensive. Modem alternative methods should be faster whilst maintaining sensitivity. Immunomagnetic separation (IMS) methodology has been investigated and appears promising for rapid bacterial detection in unrelated food and environmental samples. In this study, a commercial sensor which combined IMS with electrochemiluminescence (ECL) was evaluated for the detection of E. coli 0157 in unrelated food matrices. Emitted signals …

Evaluation Of The Host Range Of Polyvalent Staphylococcal Bacteriophages To Control Mrsa (Staphylococcus Aureus) From Irish Hospitals, Mohamed Farag M. Elbreki

Theses

This study describes firstly, the assembly of a collection of a varied spectrum of staphylococci which can be used to test the efficacy of bacteriophages for the biocontrol of problematic members of this genus. The collection assembled includes a variety of multi-antibiotic resistant MRSA (methicillin resistant S. aureus) strains, hVRSA (hetero vancomycin resistant S. aureus), VRSA and also teicoplenin resistant isolates. It also included a broad range of species of coagulase-negative {non-aureus) staphylococci including S. caprea, S. haemolyticus, S. saprophyticus, S. epidermidis, S. chromogenes, S. capitis, S. hominins and S. hyicus. All strains were characterized by morphology on Baird Parker, …

Development Of A Genomic Approach For The Study Of A Coryneform Bacterial Collection., Carole Feurer

Theses

In the last few years, genomics has profoundly changed research in the biological sciences and in particular in microbiology. Recent studies have demonstrated that comparative genomics is a powerful approach contributing to a deeper understanding of the evolution of microorganisms. Bacterial collections are important resources of microorganisms, however, the potential that genomics has to offer remains to be realised as it is still virtually absent in any study involving strain collections. This feature thus framed the experimental objectives for this study, whose aim was to define the most comprehensive way to apply genomic based methods (high throughput sequencing and bioinformatics) …

Campylobacter Spp: A Molecular Investigation Of Transmission Through The Food Chain In Ireland, Brigid Lucey

Theses

The purpose of this study was to investigate the epidemiology of thermophilic Campylobacter infections in Ireland, and to assess antimicrobial resistance among animal isolates and its relevance to human enteric infection with Campylobacter. The first part of the study focused on 84 isolates of human, poultry and porcine origins, isolated between 1996 and 1998 in the Cork region. These isolates were identified to species level using a combination of biochemical and molecular methods. Campylobacter jejuni (C. jejuni) was the predominant organism among human and poultry isolates, whilst all of the porcine isolates examined were identified as C. coli. DNA amplification …

Β-Lactamase: Evolution Of Extended Spectrum Enzymes, Priscilla Shine

Theses

β-Lactam antibiotics are commonly used antimicrobial agents in clinical medicine. Because of their frequent use it is perhaps not surprising that resistance to these agents has increased over the past few decades, thus compromising the therapeutic advantages offered by these agents. The most common cause of resistance to β-lactam-based antibiotics has been the evolution of a group of enzymes known as β-lactamases, which act by inactivating the drug through structural modification. Plasmid-encoded TEM β-lactamases are examples of these hydrolytic enzymes and are associated with the amoxicillin resistance reported in over 50% of all E. coli isolates.

More recently β-lactamase enzymes …

The Investigation Of Rna Viruses Using The Atomic Force Microscope, Michelle Moloney

Theses

The subject of viral entry into, and subsequent progeny virus egress, from cultured cells, has been extensively studied using numerous scientific techniques in fields ranging from cell culture to biochemistry to microscopy. The atomic force microscope (AFM) is a novel, developing instrument with unprecedented capabilities and this study was undertaken to observe enveloped Semliki Forest virus (SFV) and non-enveloped Theiler's Murine Encephalomyelitis virus (TMEV) entry into and egress from cultured cells using the AFM. Virus particle structure of both enveloped and non-enveloped viruses was also directly examined.

Cytopathic effect studies revealed that TMEV's are unable to produce progeny viruses in …

The Molecular Characterisation Of Selected Epidemic Associated Gram Negative Pathogens In Southern Ireland, Mairéad Daly

Theses

This study was undertaken to evaluate various molecular techniques for the analysis of Gram negative bacterial associated epidemics. The first investigation dealt with bovine mastitis outbreaks, where the causative agent was identified as Pseudomonas aeruginosa. Epidemiological findings, suggested that all herds were infected from teat wipes that were contaminated with this organism. Initial investigations using the polymerase chain reaction (PCR), indicated a possible clonal relationship between all outbreak linked strains, with one exception. This finding was confirmed following pulsed-field gel electrophoresis (PFGE) and ribotype analysis. PCR was again employed to study a rather unusual epidemic, involving Salmonella tel-el-kebir over a …

The Molecular Epidemiology Of Rotavirus In Ireland, Fiona O'Halloran

Theses

Between 1997 and 1998, 3,136 cases of rotavirus diarrhoea were detected in Irish children less than 2 years of age. Hospital inpatients accounted for 80% of these infections, with the remainder being diagnosed in general practice. A large percentage of infections were detected in neonates, suggesting a possible inadequate maternal derived protection from existing indigenous strains. This feature suggested the possible existence of ‘novel’ strains circulating in Ireland. No data describing the epidemiology of rotavirus strains in this country currently exists. Furthermore no assessment of the potential health-economic impact or quantitation of potential disease burden was ever undertaken

Three hundred …

The Surveillance And Control Of Foodborne Diseases, Donal J. Daly

Theses

There is great variation in the extent of surveillance of foodbome disease throughout the world. Some countries contribute important epidemiological and microbiological data to the WHO Surveillance Programme for Foodbome Diseases in Europe. While the UK is a major contributor to this programme, data from Eire has been non-existent. Trends in the incidence of foodbome disease in the UK may have particular relevance to Eire given the similarity of culture. Microbiological and epidemiological data in relation to foodbome pathogens, foods most frequently incriminated in outbreaks, places where outbreaks occur, together witli the main contributory factors are discussed. The broader area …