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phage therapy
Organic production will probably find phage therapy an acceptable
replacement for antibiotics. It might be useful to stress the need for
research funds from USDA to promote this application , funds are
presently lavish for GM products but the phage application could be more
economic in the long run.
Science Oct 25 2002: 730
Food and Agriculture: Testing Grounds for Phage Therapy
Richard Stone
Last month, the U.S. Food and Drug Administration tightened another
screw in its effort to curb the spread of antibiotic resistance from the
burgeoning use of agricultural drugs. The agency aired draft regulations
requiring manufacturers to test potential livestock pharmaceuticals for
their ability to help pathogens acquire resistance to human drugs. But
farmers are concerned that they could be left with fewer weapons to
combat Listeria and other food-borne pathogens that cause several
hundred deaths each year in the United States alone. "When farmers are
told they can't use any antibiotics used in humans, they say, 'What do
we use?'" says Toney Ilenchuk. His firm, Biophage Pharma in Montreal,
Canada, believes it has part of the answer: bacteriophages against
Salmonella and pathogenic strains of Escherichia coli.
Ilenchuk and other advocates are also eyeing the use of phages--viruses
that attack bacteria--in food processing. The Baltimore, Maryland-based
firm Intralytix already has a permit from the U.S. Environmental
Protection Agency to test a phage against the bacterium Listeria
monocytogenes in a food-processing plant, although in this trial the
phages cannot be applied to surfaces that come into contact with food.
The company hopes to have its anti-Listeria phage on the market by early
next year. Intralytix is also developing phage preparations to spray on
eggs to reduce Salmonella contamination. It would be too daunting to go
after all 2400 or so Salmonella serogroups, "but we can target the five
or six serogroups most commonly associated with human illness," says
Intralytix co-founder Alexander Sulakvelidze, who directed the State
Microbiology Laboratory in Tbilisi, Georgia, before emigrating to the
United States a decade ago
Fresh-cut produce might also be candidates for phage treatment: A team
at the U.S. Department of Agriculture (USDA), working with Intralytix,
has found that phages are more effective than chlorine at ridding cut
fruits and vegetables of Salmonella. At least two dozen other phage
firms worldwide are hoping to get a foothold in the food and livestock
market.
Shadowing the corporate push is surging academic interest in using
phages to improve food safety. For example, a team led by
microbiologists Donna Duckworth and Paul Gulig of the University of
Florida, Gainesville, has isolated phages against Vibrio vulnificus, a
bacterium sometimes found in raw oysters that can trigger severe illness
in people. The researchers have used these phages to cure infected mice
and are trying to harness the phages for depurating oysters for human
consumption. In a similar vein, Elizabeth Kutter's team at Evergreen
State College in Olympia, Washington, is working with USDA to find
phages that can clear the deadly E. coli O157:H7 from cattle guts. The
strain doesn't seem to bother cows, but outbreaks traced to undercooked
hamburgers and unpasteurized fruit juices have killed scores of people.
All these potential applications would require regulatory approval. But
enthusiasts hope that the very ubiquity of phages will make them an easy
sell. They are "the ultimate clean, green, ecofriendly disease-control
system," pitches Tony Smithyman of SPS, a phage-therapy firm in Sydney,
Australia. "We're working in tune with nature."
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