Unraveling aerotolerancy of campylobacter jejuni and campylobacter coli using a transcriptomic approach

Campylobacter spp. cause foodborne illness on a global scale. Despite their sensitivity to atmospheric oxygen, Campylobacter spp. often survive O₂ exposure during meat processing. The genetic mechanisms underlying aerotolerance in Campylobacter spp. are not well understood. In this study, C. jejuni strain S2-20 and C. coli strain WA333 were subjected to atmospheric O_2, and transcriptomes were analyzed at multiple timepoints, using RNA-Seq technology. In both species, a large number of genes involved in ribosomal formation and oxidative phosphorylation were downregulated at most timepoints. Upregulation of genes associated with iron acquisition was noted in C. coli but not C. jejuni. Several genes involved in molybdate and tungstate uptake were upregulated in C. jejuni. Molybdate is important for enzymes that allow the use of alternate electron acceptors instead of O₂. This finding, along with the downregulation of genes involved in oxidative phosphorylation, suggests a shift in C. jejuni from aerobic to anaerobic respiration during aerobic conditions, possibly reducing oxidative stress. Our results also suggest that C. jejuni and C. coli utilize different strategies to survive aerobic conditions. To our knowledge, this is the first study to use RNA-Seq to investigate C. coli aerotolerance on a genome-wide scale.