DGGE and qRT-PCR comparison of wild-type and chitosan "adapted" isolates of Campylobacter jejuni NCTC 11168

Intro: Campylobacter jejuni is a notable burden to public health on a global scale. The biopolymer chitosan has shown various antimicrobial activities against both bacteria and fungi alike. With the ever increasing demand for more natural alternatives harbouring antimicrobial properties, as oppose to more chemically synthetic preservatives, chitosan has received attention with respect to use in food packaging and other food-related applications due to its GRAS nature. Aim: To determine differences between a wild-type and a chitosan “adapted” isolate of C. jejuni NCTC 11168 with respect to mutations and gene regulation using DGGE and qRT-PCR, respectively. Methods: DGGE analysis was performed using a DCode mutation detection system (BioRad, USA). A parallel gradient polyacrylamide gel (8%) was run for 3.5 hours at 200V after an initial 15 minutes at 20V. After staining the gel for 15 minutes, it was de-stained and visualised using a Gel Dock (G:Box, Syngene). Gene expression was analysed using qRT-PCR (StepOnePlus, Applied Biosystems) comparing chitosan- treated versus non-treated (control) for each isolate types in several genes of interest including CheY, FlaA and CmeB. Results: Preliminary studies suggest differences in gene expression in several genes when comparing the wild-type to the “adapted” isolate of C. jejuni when exposed to chitosan. Conclusion and Impact of research: Differences observed between the wild-type and chitosan “adapted” isolates highlight potential mechanisms whereby C. jejuni is able to overcome exposure to chitosan and thus remaining a problematic pathogen, despite its fastidious nature.