April 2, 2012

Poultry Campylobacter vaccine presented in Ireland

A vaccine against the Campylobacter species is being presented in Ireland, as an alternative to reduce cases of human food poisoning, according to an expert.

The preliminary work on a Campylobacter vaccine was presented at the Society for General Microbiology's Spring Conference in Dublin, Ireland.

"It has been shown that about 65% of chickens on retail sale in the UK are contaminated with Campylobacter," explained Mike Konkel (Washington State University, Pullman), the researcher, in a press statement.

"Ideally, the best way to prevent contamination is to stop chickens on the farm from becoming colonised with this microorganism in the first place, which could be achieved by vaccination. Our goal within the next six months is to test a vaccine for chickens that will reduce Campylobacter colonization levels."

Campylobacter species are one of the most common causes of bacterial gastroenteritis in humans, accounting for an estimated 400-500 million cases worldwide each year. Acute illness in humans is associated with C. jejuni invasion of intestinal epithelial cells; by contrast, the intestinal tract of chickens can be colonized without any ill-effects.

To investigate the mechanisms underlying this difference, Konkel's group analysed the maternal antibodies that are passed from hens to their chicks, protecting the chicks from becoming colonised by Campylobacter in the first week of life.

They found that the maternal antibodies attack specific proteins expressed on the surface of C. jejuni, known as CadF and FlpA. These proteins are needed to facilitate binding of the bacteria to the extracellular matrix component fibronectin, which in turn "sets the stage for the invasion of human intestinal cells," explained Konkel.

Thus, CadF and FlpA are potentially useful components in a vaccine designed to reduce C. jejuni colonization of poultry, he said.

Controlling food-borne illness through vaccination would have a significant impact in both developing and developed countries, said Konkel, who stressed that a safe food supply is central to human health.

"A 1% reduction in the number of cases of food-borne illness would save the UK around GBP20 million (US$32 million) per year. In developing countries, where people and food animals often share the same environment, diseased animals also pose a direct public health risk; vaccination would help mitigate this risk," Konkel concluded.