Date of Award

2013

Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy

Department

Biological Sciences

First Advisor

Dr. Aidan Coffey

Abstract

Acinetobacter baumannii is a pathogen, which has an increasing prevalence of multidrug resistance. It exists widely in natural environments, and frequently in health-care settings where it has proven difficult to eradicate using antibiotic therapy. A possible alternative to conventional antibiotics is the use of bacteriophages (phages) as antibacterials. In this project, extensive screening of environmental samples such as soils, sewage and waters was undertaken to identify suitable phages. Three phages were successfully isolated from municipal waste in the Cork area. These were subsequently characterized in detail and examined by electron microscopy, which showed that they were all of the Myoviridae family. They were subsequently applied successfully for the elimination and control of biofilms, which are a big problem in the medical context. Following this, one of the three phages (Ome3) was subjected to complete genome sequencing and the genome was found to be extremely large at 234.9 kb. The genome was annotated and functions could be assigned (on the basis of bioinformatics) to 323 Open Reading Frames (ORFs). Two ORFs were selected for further analysis, namely those encoding two distinct muramidase (lysozyme) enzymes. Both were cloned into an expression vector pQE60, expressed and demonstrated to have full activity by zymogram following purification. The purification achieved for one of the enzymes namely LysME3a was sufficient to demonstrate clearing of a live turbid Acinetobacter baumannii culture.

Access Level

info:eu-repo/semantics/openAccess

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