Listeria monocytogenes : a genomic perspective on its pathogenesis, persistence and bacteriophages /
Aidan Casey.
- xxx, 289 pages : color illustrations, tables ; 30 cm
- Ph.D - Biological Sciences .
Thesis (Ph.D) - Cork Institute of Technology, 2015.
Includes bibliographical references.
The object of this study was to investigate the genetic characteristics of Listeria monocytogenes that contribute to the threat it poses to the food processing industry. Transcriptomic analysis of a persistent L. monocytogenes isolate following exposure to an industrial detergent identified key upregulations in biological processes involved in peptidoglycan biosynthesis, chemotaxis and motility. Two bacteriophages against serotype 4b and 4c isolates of L. monocytogenes were isolated and sequenced. Comparative genomic and functional analysis identified the receptor binding proteins in each phage, while transmission electron microscopy demonstrated a conserved basephate architecture which also exists in other gram-positive phages. Comparative genomics of four serotype 1/2b isolates, including an isolate that caused a sub-clinical infection (DPC6895), identified specific genes that may be important for L. monocytogenes pathogenesis. Attenuated virulence in strain DPC6895 was attributed to a cumulative loss of functionality rather than a single event, exemplified by notable absences of the Stress Survival Islet and Listeria Pathogenicity Island 3 from its genome. Finally, the true discriminatory power of whole genome sequence analysis was assessed on two pairs of geographically distant, yet closely related L. monocytogenes isolates, which identified key differences in their antibiotic resistances and virulence potentials. - (Author's abstract)
Listeria monocytogenes. Listeria. Foodborne diseases. Food industry and trade. Bacteriophages--Genetics. Genomics.