Hyperinvasiveness in the major food-borne pathogen Campylobacter jejuni

Campylobacter jejuni is a common cause of human gastrointestinal infections. Invasion of host epithelial cells is believed to be an important virulence Mechanism of this bacterium. C. jejuni strains vary in their ability to invade the human epithelial cells and some of the strains are hyperinvasive. The aim of this work was to find the molecular basis of this hyperinvasive phenotype. The previously studied hyperinvasive phenotype of C. jejuni 01/51 in INT-407 cells was verified using Caco-2 cell based invasion assay and the assay was set up at Nottingham Trent University by selecting blood agar for 48 hours as the pre-assay bacterial growth conditions and 100 multiplicity of infection as the starting inoculum. Seven hundred and sixty eight mutants generated in this strain by random transposon insertional mutagenesis were screened for their ability to invade human intestinal epithelial cells in an in vitro model and 174 mutants were selected for further studies. The motility of selected mutants was determined and 40 mutants that showed more than 75% motility compared to wildtype strain, with a very low level of invasion were selected for reconfirmation of this reduced invasion phenotype using standard INT-407 and Caco-2 cells based invasion assays. Localisation of the transposon insertion site by plasmid rescue was attempted in 15 mutants that showed very low levels of invasion in both eukaryotic cell lines.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

Nottingham Trent University

Year dc:date.issued

2009

Author dc:creator

• Javed, MA

Language dc:language

en