Attachment, invasion, and translocation of Campylobacter jejuni in pig small-intestinal epithelial cells

Campylobacters are susceptible to environmental conditions such as starvation, temperature, and oxidative stress. Species such as Campylobacter jejuni have developed a number of mechanisms for responding to these conditions. We conducted a study to investigate whether survival of C. jejuni and pathogen-host cell interactions such as adherence, invasiveness, and intraepithelial survival in pig small-intestinal (PSI) epithelial cells are altered in response to starvation, changes in temperature, and atmospheric oxygen concentration. We assessed the ability of C. jejuni to translocate across polarized intestinal epithelial cell monolayers by measuring transepithelial electrical resistance (TER). Following heat stress, we observed loss of C. jejuni culturability but not viability. Heat-stressed C. jejuni adhered efficiently to pig intestinal epithelial cells, but their invasiveness was significantly impaired when compared with unstressed C. jejuni. Prolonged exposure to atmospheric oxygen reduced the ability of C. jejuni to adhere to intestinal epithelial cells, whereas brief exposure increased invasiveness and intraepithelial survival. By comparison, nutrient limitation reduced adherence, invasiveness, and intracellular survival of C. jejuni. Adherence of C. jejuni strongly affected the pig intestinal epithelium, as reflected by a significant decrease in TER of polarized intestinal epithelial cells. No correlation between TER and the translocation capacity of C. jejuni was observed. Additionally, campylobacters were detected in the basal chamber of a functional small-intestinal epithelial cell model at 3 hours post infection, without a significant reduction in the TER value, suggesting transcellular transport of C. jejuni into the body.