Molecular Interrogation of Campylobacter Infection
Lau, Sok Kiang
Thesis or dissertation
University of Exeter
Abstract Campylobacteriosis is common in both developing and developed countries. Although there had been numerous studies performed to gain a better understanding of the disease, much still remains to be unravel. In this project, the interactions between the bacteria and host cells or organisms were interrogated. Raman based imaging was initially investigated using an established Salmonella Typhimurium and cell infection model. The results obtained showed the potential for real-time imaging. However, due to the instability of the laser system of the microscope, reproducible results could not be obtained. Therefore, this technique was not applied to Campylobacter jejuni. Zebrafish embryo was established as a new infection model suitable for C. jejuni studies. C. jejuni strains and mutants were screened using this model to determine their virulence. This model was used to screen two type six secretion system mutants constructed in this study. The results obtained showed that one of the mutants, Cj1DtssM(syn)::kanR_cas, was attenuated in the ZFE model. Subsequent competitive index challenges performed in piglets with C. jejuni wild-type and the two T6SS mutants, also showed that Cj1DtssM(syn)::kanR_cas was attenuated. Both T6SS mutants had shown increased adherence to macrophages and Cj1DtssM(syn)::kanR_cas also showed increased cell invasion. Together, these findings suggested that the T6SS is involved in establishment of infection in ZFE and piglet and as well as in adhesion and invasion of macrophages.
PhD in Biological Sciences