UK – Researchers at the London School of Hygiene & Tropical Medicine (LSHTM) have launched a new investigation into how Campylobacter jejuni, a leading cause of foodborne illness worldwide, competes with other bacteria and adapts to different host environments.
The project is supported by a £850,000 (US$988,711.50) award from the UK Research and Innovation Biotechnology and Biological Sciences Research Council through its responsive mode funding scheme.
The study focuses on molecular mechanisms that allow C. jejuni to persist in poultry while causing illness in humans, a contrast that continues to challenge food safety and public health systems.
Pathogen common in food systems, severe in humans
Campylobacter is among the four most common global causes of diarrheal disease. While it typically colonizes the intestines of poultry without causing symptoms, ingestion of as few as 100 bacterial cells can trigger illness in humans.
Symptoms may include diarrhea, fever, and abdominal pain, with severe cases involving bloody stools.
In low-resource settings, infections are especially prevalent among young children and are linked to high levels of illness and death. The bacterium is most often transmitted through contaminated poultry meat, unpasteurized milk, and untreated water.
Investigating bacterial competition at the molecular level
The project is led by Dr. Ozan Gundogdu and the Enterics Research Team at LSHTM, in collaboration with Dr. Ezra Aksoy of Queen Mary University of London and Professor Amirul Islam Mallick of the Indian Institute of Science Education and Research Kolkata.
The researchers are examining a structure known as the Type VI Secretion System, or T6SS, which has been identified in many disease-associated strains of C. jejuni.
The T6SS acts as a microscopic delivery system that injects toxic proteins, known as effectors, into neighboring bacteria. This allows Campylobacter to eliminate competitors and secure space and nutrients within the gut.
Recent work by the LSHTM team has shown that this system may play a role in how the bacterium adapts to complex gut environments, including those of chickens and humans.
Studying poultry and human gut environments side by side
The new research will explore how the T6SS functions differently in poultry and human intestinal settings. By comparing these environments, the team aims to understand how bacterial competition shapes gut microbial communities and influences infection outcomes.
The study will also examine how these molecular tools affect the balance between Campylobacter and other microbes, shedding light on why the bacterium remains largely harmless in poultry but causes disease in humans.
Implications for antimicrobial resistance and food safety
The rise of antimicrobial resistance in Campylobacter has increased pressure on food safety systems to find alternatives to traditional antibiotics. Resistance to commonly used antimicrobials has been reported in multiple regions, complicating treatment and control efforts.
By clarifying how C. jejuni survives and spreads within the food chain, the researchers aim to identify new points of intervention. Understanding how bacterial toxins function could inform the development of targeted antimicrobials or vaccine strategies designed to limit transmission from poultry to humans.
Dr. Gundogdu noted that, compared with other gastrointestinal pathogens, the mechanisms by which Campylobacter causes disease remain less well characterized. The project is intended to address that knowledge gap by focusing on bacterial survival strategies rather than clinical symptoms alone.
As poultry remains one of the primary sources of human Campylobacter infection, insights from this work may inform future risk reduction strategies across farming, processing, and public health surveillance systems.