Microbiology Commons^™

A Diagnostic And Control Programme For Johne’S Disease On Irish Dairy Farms, Aideen Kennedy

Theses

Johne’s disease (JD) is an enteritis of ruminants with potential zoonotic implications. JD diagnosis and control present difficulties given JDs prolonged subclinical nature. In order to improve JD control in Ireland, PhD aims included conducting a national survey documenting high-risk husbandry practices employed on Irish farms, thereby targeting areas for improved management. Furthermore as JD has been associated with on-farm economic losses internationally, this research programme aimed to analyse production losses associated with testing JD ELISA positive on Irish dairy farms. A longitudinal study was also conducted to assess if successful JD control can be achieved using gold-standard protocols. Due …

Metabolic Characteristics Of Macrophage Activation With Phenotype Microarrays, Tanya Kathryn D'Souza

Theses

Inflammation is a natural protective response and is characterised by the activation of numerous immune cells, including macrophages which can release a variety of inflammatory mediators. Macrophages play a flexible role in the initiation and effector phases of the immune response and change their behaviour to respond to environmental stimuli. The main objectives in this study were to create and characterise different macrophage behaviours and employ a novel metabolic characterisation platform the Phenotype Microarray^TM to attribute additional characteristics to the currently well recognised phenotypes. Five activated macrophage states were demonstrated and characterised. Unactivated macrophages (MO) demonstrated undetectable levels of …

Mycobacterium Species Identification In An Acute Hospital: Towards Rapid Identification, And Improved Epidemiology, Using Novel Mass Spectrometry Analysis, James Anthony O'Connor

Theses

Mycobacteria are a heterogeneous group of bacteria that cause a wide spectrum of disease, including Tuberculosis (TB), the single biggest killer worldwide. The genus also incorporates over 170 nontuberculosis (NTM) species, many of which are opportunistic pathogens. The aim of this project was to ascertain the burden of mycobacterial disease in the region and to determine the efficacy of Matrix-Assisted Laser Desorption/Ionisation time-of-flight (MALDI-tof) mass spectrometry (MS) for novel uses as a rapid identification method for clinical mycobacteria and as a typing tool for Mycobacterium tuberculosis complex isolates. A five-year retrospective epidemiological study of the region was conducted, the first …

Characterisation Of Bacterial Extracellular Polysaccharides (Eps) And Other Complex Carbohydrates With Prebiotic Potential, Padraigin Murphy

Theses

Prebiotics are selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microbiota that confers benefits upon host well-being and health’ It is not the prebiotic by itself but rather the changes induced in microflora composition that is responsible for its effects. Several sources of prebiotic were used in this study, namely extracellular polysaccharides (EPS) originating from Lactic Acid Bacteria (LAB), barley, oat. Laminaria digitata. Laminaria hyperborea and Saccharomyces cerevisiae. EPS-producing LAB were isolated from a wide variety of environmental and gastrointestinal niches. The strains were typed and classified according to their EPS-producing ability …

The Detection And Analysis Of Selected Pathogens In The Water Supply Of Dairy Cohort Herds., Niall Drummond

Theses

The issue of food safety is a growing concern to Irish agriculture and to the food industry. In the last twenty years, many novel pathogens, which can cause concern to the food industry, have been identified. Organisms such as Verocytotoxigenic Escherichia coli (VTEC) cause hemorrhagic colitis and Haemolytic Uremic Syndrome (HUS), which is the major cause of acute renal failure in children in many countries, and it’s presence in food is a cause of growing concern. Other pathogens causing concern are those implicated as causative agents of Acute Gastroenteritis (AGE) and these can be bacterial, viral and parasitic organisms.

Consumption …

Mupirocin Resistance In Staphylococci: An Investigation Of Current Status And Potential Alternative Therapies, Susan O'Shea

Theses

Mupirocin is a topical antibiotic used in hospital infection control practices to control transmission of staphylococci, in particular MRSA, which has become a major problem in Irish hospitals and has a significant impact on patient morbidity and mortality. Overreliance on mupirocin to eradicate MRSA carriage and to prevent infection has led to mupirocin resistance among staphylococcal species. Two distinct types of resistance have developed within strains: low'-level mupirocin resistance (LMR) and high-level mupirocin resistance (HMR).

The aim of this study was to assess the prevalence and types of mupirocin resistance in a large population of clinical staphylococcal isolates including Methicillin …

Clostridium Difficile: Comparative Evaluation Of Two Detection Techniques And Characterisation Of Clinical Isolates., Rebecca Dennehy

Theses

Clostridium difficile is one of the most common causes of antibiotic associated diarrhoea. The presence of C difficile in stool samples may be detected by a variety of means including enzyme immunoassays and culture. Enzyme immunoassays detect the presence of the toxins produced by the organism, toxin A and/or toxin B, but are known to lack sensitivity. The aim of this study was to compare the commercial ELISA assay currently used for the detection of C difficile toxins in Waterford Regional Hospital to culture for the organism to selective media. To compare the sensitivity of the two methods serial dilutions …

Evaluation Of Four Novel Broad-Host-Range Antimicrobial Agents., Jiahui Guo

Theses

The overall objective of this thesis was to evaluate the antimicrobial effects of four novel broad-host-range antimicrobial agents. The first was a milk-derived lipoprotein developed by Westgate Biologicals with the support of Enterprise Ireland. This lipoprotein which was designated LactiSAL, was evaluated against a wide range of bacterial species associated with humans. Essentially, the LactiSAL was incorporated at a variety of concentrations into agar media, which were appropriate for cultivation of the different genera. Agars were examined for colony formation, after which it was possible to quantify the minimal inhibitory concentration for each genus. Subsequently, LactiSAL was incorporated at levels …

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) …