Open Collections

Investigating the synergistic antimicrobial effect of carvacrol and zinc oxide nanoparticles against Campylobacter jejuni

University of British Columbia

Foodborne illness is a growing concern world-wide, and Campylobacter in particular has been reported to cause approximately 145,000 foodborne illness cases every year in Canada. A recent annual report from the Canadian Integrated Program for Antimicrobial Resistance Surveillance reveals an increasing trend of antibiotic-resistant Campylobacter isolated from poultry sources across Canada. The large number of foodborne illnesses and emergence of the resistant strains of Campylobacter pose a serious threat in the agri-food industry. Hence, there is increasing urgency to find alternatives to conventional antimicrobials to reduce the prevalence of Campylobacter in the food supply chain while reducing the likelihood of resistance. Combining antimicrobials is a potential intervention strategy to reduce the growth of pathogens by expanding the spectrum of antimicrobial activity. In this study, carvacrol and zinc oxide nanoparticles (ZnO NPs) were investigated in regards to their synergistic antimicrobial effect against C. jejuni. The combination of these two agents for treatment is based upon current evidence of their individual antimicrobial activity. The objectives of this thesis project were to (1) determine the synergistic antimicrobial effect of carvacrol and ZnO NPs against C. jejuni, (2) investigate the macromolecular fingerprints and gene expression profile of C. jejuni after the combinational treatment, and (3) explain the potential mechanism of the synergistic antimicrobial effect. In this work, a macrobroth dilution method was used to test the antimicrobial effect of the compounds against C. jejuni. The macromolecular fingerprints of C. jejuni cells treated with carvacrol and ZnO NPs were investigated using confocal micro-Raman spectroscopy, whereas Real-Time Quantitative Polymerase Chain Reaction (RT-qPCR) was employed to study the variation in bacterial gene expression after the antimicrobial treatment. The synergistic antimicrobial effect of carvacrol and ZnO NPs against C. jejuni was clearly demonstrated using the time-kill curve. The macromolecular fingerprints and gene expression profile revealed the role of carvacrol in the synergistic antimicrobial effect against C. jejuni. The results of this study provide fundamental knowledge about bacterial stress in response to the synergistic antimicrobial effects. This antimicrobial combination may be utilized as an intervention strategy to reduce the prevalence of C. jejuni in agri-foods.

Text

2017-01-21

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/60248

Food Science

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/