Poultry handling-related stress alters membrane composition, extracellular vesicle production, survival, and virulence in <i>Campylobacter jejuni</i> Bf

ABSTRACT We investigated the adaptation of the aerotolerant Campylobacter jejuni Bf strain to conditions mimicking the poultry slaughter process. We showed that C. jejuni Bf survives and actively multiplies under combined thermal and oxidative stress. Stress exposure induces cell rounding, loss of motility, remodeling of membrane composition, decreased membrane fluidity, and metabolic reprogramming with increased intracellular ATP levels. While maintaining the lipid composition of its plasma membrane, C. jejuni modulates the lipid composition of its extracellular vesicles when exposed to stress. Notably, stressed C. jejuni cells release extracellular vesicles with increased toxicity toward the epithelial barrier of Caco-2 cells, potentially facilitating invasion of the gut epithelium. IMPORTANCE Campylobacter infections are one of the leading causes of foodborne gastroenteritis worldwide. Campylobacter readily enters the food chain and is transmitted to humans, primarily through the consumption of contaminated poultry meat. The high prevalence of aerotolerant human Campylobacter jejuni isolates suggests a correlation between their ability to survive under aerobic conditions, virulence, and resistance to harsh stress conditions. However, the underlying mechanism remains unclear. Our results show that C. jejuni extracellular vesicles are part of a survival strategy that links environmental adaptation with pathogenicity.