Fall 2009 » Research Briefs » Poultry Scientists Use Viruses to Fight Bacteria

Poultry Scientists Use Viruses to Fight Bacteria

March, 2009

Scientists at the University of Arkansas and the USDA Agricultural Research Service are updating century-old technology to fight illness-causing bacteria in poultry by infecting them with viruses.

"There has been growing concern that use of antibiotics has been causing an increase in antibiotic-resistant strains of bacteria that cause diseases," ARS researcher Bill Huff said. "We felt it was important to find alternatives to antibiotics. These viruses, called bacteriophages give us another tool to battle disease-causing bacteria and reduce pressure on bacteria to develop resistance to antibiotics."

"Bacteriophages are very specific viruses," UA poultry scientist Billy Hargis said. "They don't harm people, animals or plants - only a narrow range of bacteria."

Hargis works with bacteriophages that attack salmonella, and Huff works with bacteriophages that attack E. coli. In both studies, they use them to protect poultry from respiratory infections.

Bacteriophages are much smaller than the bacteria they attack. When one comes into contact with a target bacterium, the phage attaches to a site on the cell's surface. It penetrates the cell wall and injects its DNA into the host. The DNA rewrites the cell's reproductive programming to replicate bacteriophage. It also produces an enzyme that "lyses" the cell - bursts it open, kills it and releases new virus.

The entire life cycle takes about 30 minutes to complete.

Both scientists found aerosol spray worked best for delivering the phages to large numbers of chickens or turkeys. The birds needed large doses for effective and consistent protection, but researchers can grow large quantities in the lab.