September 3, 2008

US scientists are studying vaccines that act on multiple pathogens and are hoping to expand the list of pathogens the vaccines could act on.

With funding from USDA's Cooperative State Research, Education, and Extension Service (CSREES) National Research Initiative (NRI), scientists in Arizona are developing a new vaccine for Avian Pathogenic Escherichia coli (APEC), hoping it would improve animal and human health.

APEC caused an estimated US$80 million in losses in 2002 and has the potential to be as harmful as E. coli O157:H7.

The genetic similarity between APEC and human E. coli has led scientists to suspect poultry as a source of Extra-intestinal Pathogenic E. coli (ExPEC), which is associated with urethral infections, sepsis, and meningitis.

Dr. Roy Curtiss and colleagues at Arizona State University began by identifying how E. coli evaded the host's immune system. The researchers used the E. coli bacterial genome to identify the specific genes responsible for triggering its harmful effects.

The vaccine produced during this project may lead to additional protection for humans against another pathogen, Salmonella.

One challenge for vaccine production for E. coli and Salmonella groups is that the effort is complicated by the genetic diversity of each bacterium.

Curtiss has already developed three vaccines that are effective against multiple strains of Salmonella in livestock. The vaccines, which were approved by the FDA for use in swine and poultry, are currently on the market.