Microbiology Commons^™

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 …

Analysis Of Adenovirus And Bovine Coronavirus., Kevin Lane

Theses

This investigation involved the analysis of selected gastroenteritis viruses, adenovirus and bovine coronavirus, obtained from faecal samples, collected from hospital and diagnostic laboratories respectively in Cork city, Ireland. The viruses isolated from these samples were subjected to analysis using cell culture and nucleic acid extraction. In addition adenovirus was analysed using PCR and PCR followed by restriction endonuclease digest. Many samples contained more than one gastroenteritis virus, the virus of interest and a natural co-infection with rotavirus species. Rotavirus infections in Ireland have been extensively studied and we were interested in studying singly and doubly infect samples.

Bovine enteric coronavirus …

Epidemiology And Drug Resistant Profiles Of Candida Species, In Cork Hospitals., Emma Mccurtin

Theses

Candida causes superficial infections in healthy individuals; however in the immunocompromised host Candida can cause invasive, systemic infections and is a significant cause of morbidity and mortality. This is not due to a more virulent phenotype but to a weakened immune system unable to fight this opportunistic pathogen. The immunocompromised population is ever increasing, due to medical advancements and more aggressive treatments, and hence is the need for epidemiological data of these potentially life threatening infections. The aim of this study was to provide an epidemiological snapshot, of Candida infections from the immunocompromised population in Cork hospitals. Surveillance programmes from …

Design Of A Multiplex Pcr Assay For The Detection Of Neisseria Gonorrhoeae., Elizabeth J. O'Callaghan

Theses

The incidence of N. gonorrhoeae infections in Ireland has been steadily increasing since 2003. Culture is currently the preferred method of diagnosis, however the sensitivity of culture can be low. In recent years there has been increased interest in non-culture techniques such as polymerase chain reaction (PCR). Many of the PCR assays available have been shown to cross-react with commensal organisms, producing false positive results. This study aimed to improve the detection of N. gonorrhoeae by designing a multiplex PCR assay that used two N. gonorrhoeae genes as targets, thereby providing dual detection and confirmation of a positive result. PCR …

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 …

Quantification Of Mrna Expression Of Her2/Neu, Estrogen Receptors Eralpha And Erbeta, And Progesterone Receptor Using Real-Time Reverse Transcription Pcr In Small Tumor Biopsies, In Human Breast Cancer, Evonne Marie. Mc Cabe

Theses

Early detection is an effective means of reducing cancer mortality. Early detection greatly improves treatment options and the chances for successful treatment. The prognosis for patients with breast cancer is determined by well-established biological features associated with biological aggressiveness, histological grade, tumour size, and nodal involvement. Breast cancer results from multiple genetic abnormalities, and cellular differentiation, tumour growth, and metastatic potential are the end result of these changes. Identification of molecular changes is of considerable value in enhancing the accuracy of prognostic indices, and more importantly, it may indicate various changes as putative targets for therapy. In recent years a …

Molecular Epidemiology Of Antibiotic Resistant Salmonella Enterica Strains From Different Animal And Human Sources In Ireland, David George Lee

Theses

In this study, 176 isolates of Salmonella were collected from different laboratories in Ireland. All isolates were confirmed to be of the genus Salmonella by performing bacteriological and biochemical tests. Briefly, all isolates were cultured onto XLD agar after which pure cultures were verified and stocked at this institute. Definitive identification was carried out using the API 20-E system and a separate urease test was also performed on all isolates. After confirmation of the genus, all isolates were prepared for antibiotic susceptibility testing and r-types were determined using sixteen antibiotics. Depending on the antibiotic resistance profiles, isolates were selected for …

The Analysis And Characterisation Of Rotavirus And Norovirus Circulating In The South Of Ireland, Norma Reidy

Theses

On average more than 3,000 cases of rotavirus diarrhea are detected annually amongst Irish children less than 3 years of age. Rotavirus disease occurs mainly during the winter months, with peak infections detected from February to April. The symptoms of disease are diarrhea and dehydration, with 80% of patients requiring hospitalisation, The mean duration of hospitalisation is 3-4 days, with an average cost per day of €409. Eighteen percent of infections were detected in infants less than 6 months of age, suggesting inadequate maternal derived protection from existing strains, or the existence of novel strains in Ireland with little or …

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 …

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 …

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 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 …