Persistent Intestinal Colonisation and Systemic Immune Activation Following Experimental Campylobacter jejuni...

Area of Science:

• Food safety
• Veterinary immunology
• Microbial pathogenesis

Background:

• Campylobacteriosis is a major foodborne bacterial illness globally, with poultry meat being the primary source of human infection.
• Broiler chickens act as a significant reservoir for Campylobacter jejuni, where it persists asymptomatically in the gastrointestinal tract.

Purpose of the Study:

• To investigate the persistent colonization of Campylobacter jejuni in broiler chickens.
• To analyze the systemic immune responses, including antibody and cytokine profiles, following experimental C. jejuni infection.

Main Methods:

• Broiler chickens were orally challenged with the virulent ST-403 strain of C. jejuni.
• Caecal bacterial loads were quantified at multiple time points post-infection.
• Serum total and antigen-specific IgY levels, cytokines, and chemokines were measured using ELISA and multiplex assays.

Main Results:

• C. jejuni rapidly colonized the cecum and persisted throughout the study, with gradually declining but still high bacterial loads.
• Total IgY levels increased early post-infection, and antigen-specific antibodies were elevated in infected chickens.
• Distinct temporal patterns in cytokine profiles were observed, including increased IL-6 and MIP-1β, decreased IL-2 and MIP-3α, and persistently low IFN-γ.

Conclusions:

• Campylobacter jejuni establishes stable intestinal colonization in broiler chickens.
• A detectable, yet non-clearing, systemic immune response occurs in infected birds.
• These findings reinforce the role of broiler chickens as a persistent reservoir for human C. jejuni exposure, emphasizing food safety concerns.