Diverse threats posed by avian E. coli

In a groundbreaking study conducted by the University of Surrey and University of Bristol, in collaboration with Poultry Health Services, researchers have uncovered the underlying mechanisms that differentiate various strains of Avian Pathogenic E. coli (APEC).

While most E. coli strains are harmless, APEC is known to cause severe illness in poultry, resulting in both significant economic losses and animal welfare concerns.

Identifying the Dominant Strain

The study, published in Virulence, focused on a colibacillosis outbreak in UK turkeys, identifying a strain known as ST-101 as the primary cause, responsible for nearly 60% of the cases. This particular strain had not previously been recognized as a leading factor in turkey outbreaks within the UK.

Strain Behavior in Cells

Researchers, under the guidance of Dr. Jai Mehat, Dr. James Adams, and Professor Roberto La Ragione, compared ST-101 with several other high-risk APEC strains. The findings revealed that ST-101, along with ST-95 and ST-140, exhibited superior capabilities in invading and surviving within chicken gut cells and immune cells (macrophages) when compared to ST-23 and ST-117 strains.

Interestingly, despite its reduced effectiveness in cell invasion, the ST-117 strain showed a higher lethality in insect infection models, indicating that different strains have varying pathways of causing disease.

Limitations of Current Control Measures

According to Dr. Jai Mehat, the senior author of the study, “Our research indicates that a uniform approach to managing APEC infections fails to address the complexity of this issue. Current vaccination strategies tend to focus on specific strains, but may not offer protection against emerging threats. There’s an urgent need to develop vaccines that can effectively target a broader array of APEC strains.”

Professor Shahriar Behboudi, co-author and professor at the University of Bristol, adds, “Implementing broad-spectrum control measures that induce trained immunity in chickens could offer a more effective defense against diverse APEC strains, as current vaccines inadequately address new APEC threats.”

Dr. Sara Perez, co-author and clinical director at Poultry Health Services, emphasizes, “The threat posed by APEC infections to farmed poultry is significant. Enhancing our surveillance systems for poultry flocks will play a crucial role in understanding the evolution of APEC strains, ultimately protecting animal welfare and ensuring food safety.”