Investigation of growth and stress tolerance characteristics of Cronobacter spp.

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dc.contributor.advisor Hill, Colin
dc.contributor.advisor Begley, Máire Flaherty, Claire 2013-02-26T16:57:14Z 2013-02-26T16:57:14Z 2012-12 2012-12
dc.identifier.citation Flaherty, C, 2012. Investigation of growth and stress tolerance characteristics of Cronobacter spp.. PhD Thesis, University College Cork. en
dc.description.abstract Cronobacter spp. are opportunistic pathogens which can be isolated from a wide variety of foods and environments. They are Gram negative, motile, non-spore forming, peritrichous rods of the Enterobacteriaceae family. This food-borne pathogen is associated with the ingestion of contaminated infant milk formula (IMF), causing necrotizing enterocolitis, sepsis and meningitis in neonatal infants. The work presented in this thesis involved the investigation and characterisation of a bank of Cronobacter strains for their ability to tolerate physiologically relevant stress conditions that are commonly encountered in the gastrointestinal tract. While all strains were able to endure the suboptimal conditions tested, noteworthy variations were observed between strains. A collection of these strains were Lux-tagged to determine if their growth could be tracked in IMF by measuring bioluminescence. The resulting strains could be easily and reproducibly monitored in real time by measuring light emission. Following this a transposon mutagenesis library was created in one of the Lux-tagged strains of Cronobacter sakazakii. This library was screened for mutants with affected growth in milk. The majority of mutants identified were associated with amino acid metabolism. The final section of this thesis identified genes involved in the tolerance of C. sakazakii to the milk derived antimicrobial peptide, Lactoferricin B (Lfcin B). This was achieved by creating a transposon mutagenesis library in C. sakazakii and screening for mutants with increased susceptibility to Lfcin B. Overall this thesis demonstrates the variation between Cronobacter strains. It also identifies genes required for growth of the bacteria in milk, as well as genes needed for antimicrobial peptide tolerance. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2012, Claire Flaherty en
dc.rights.uri en
dc.subject Cronobacter sakazakii en
dc.subject Milk en
dc.subject.lcsh Microbiology--Research en
dc.subject.lcsh Pathogenic microorganisms en
dc.subject.lcsh Infant formulas en
dc.title Investigation of growth and stress tolerance characteristics of Cronobacter spp. en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text available en
dc.description.version Accepted Version en
dc.contributor.funder Enterprise Ireland en
dc.description.status Not peer reviewed en Microbiology en

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