Oooo, I was glad to find a ProMED posting on this, for I'd spotted it
in the /NY Times/ and was wondering how to get the poop
(journalistically speaking) to you all. And so. Thought this might
interest some of you. I'll bet this story is making certain
management-intensive rotational graziers sigh and say "amen." PS,
graziers, I'm not currently subbed to GRAZE-L--I'm digging out from
FDA REVISING ANTIBIOTIC GUIDELINES FOR ANIMALS
A ProMED-mail post
Date: Mon, 08 Mar 1999 16:49:30 -0500
From: Robert A. LaBudde
The Food and Drug Administration [FDA] has begun a major revision of
its guidelines for approving new antibiotics for animals and for
monitoring the effects of old ones because they are faced with
mounting evidence that the routine use of antibiotics in livestock may
diminish the drugs' power to cure infections in people.
The goal of the revision is to minimize the emergence of bacterial
strains that are resistant to antibiotics. Such resistance makes them
difficult or even impossible to kill. Drug-resistant infections, some
fatal, have been increasing in people in the United States, and some
scientists attribute the problem to the misuse of antibiotics in both
humans and animals. Of concern to scientists is recent studies found
bacteria in chickens that are resistant to fluoroquinolones, the most
recently approved class of antibiotics and one that scientists had
been hoping would remain effective for a long time.
A crucial component of the new guidelines will be the requirement that
manufacturers test certain new livestock drugs for a tendency to
foster the growth of resistant bacteria that could prove harmful to
people. Testing will be required for a drug both before and after its
approval. The antibiotics that would get special scrutiny are those
that are also used by humans or are related to drugs used by humans.
If the antibiotics are shown to foster bacterial resistance, they
could be banned from use as growth promoters in animals. If scientists
became aware of a problem with older antibiotics, they could also be
The proposed guidelines have drawn criticism from both sides of a
bitter debate, ongoing for three decades. At issue is the extensive
use of antibiotics in livestock: of the 50 million pounds of
antibiotics produced every year in the United States, about 40 percent
is given to animals, mostly as feed additives to promote growth.
On one side, the drug and agriculture industries were cited as saying
that the FDA is going too far toward restricting access to
antibiotics, which they insist are essential to produce safe and
affordable meat and poultry. The industries were cited as saying the
proposed rules will make drug development, already difficult and
expensive, even more so.
At a meeting held by the FDA in late January to discuss the proposed
changes, Dr. Brendan Fox, president of Elanco Animal Health, a
division of the pharmaceutical firm Eli Lilly and Co., said "We
believe the agency is greatly overstating the conclusiveness and the
implications of the data and has put forth a seriously flawed
On the other side, public-health and consumer advocates were cited as
saying that the FDA is not going far enough, because antibiotics are a
precious medical resource that should not be squandered to fatten
animals. On Tuesday, a coalition of 37 groups, led by the Center for
Science in the Public Interest, a nonprofit group based in Washington,
will petition the FDA to separately rule if a drug is used to treat
diseases in people, it can no longer be given to animals as a growth
The agency's [FDA] working proposal, or "framework," open for public
comment until April 6, will not be translated into new regulations for
about two years. Dr. Stephen F. Sundlof, director of the center for
veterinary medicine at the FDA, said the agency was acting now because
the nation is in a vulnerable period, with no new classes of
antibiotics expected to come onto the market for several years. That
makes it all the more important to preserve the potency of existing
The reason there are no new types of antibiotics in the pipeline is
during the 1980s there seemed to be more than enough, and drug
companies stopped making new ones, Sundlof said. They have since
resumed working on new antibiotics, but it can take 10 years to bring
a new drug to market.
The last new class of antibiotics approved, fluoroquinolones, came
into use in 1986. One of the common brand names is Ciprofloxacin, a
treatment for some infections like gastrointestinal illness caused by
salmonella bacteria. Sundlof said the agency was especially concerned
about averting the development of widespread resistance to this class
Sundlof was quoted as saying, "Resistance has always been a problem in
human medicine. The way we had avoided any catastrophic events was to
continue to develop new products. But it became apparent in the 1990s
that there weren't any new classes at the stage of development where
they'd be approved and available in the near future, and there was
great concern that if resistance developed to this last class of
drugs, it could have very bad ramifications for the public."
In the United States, 6 of the 17 classes of antibiotics given to
animals for growth promotion are also used to treat sick people.
Sundlof was cited as saying that it was beyond the authority of the
FDA to pass a blanket ban like the one advocacy groups wanted.
At the Centers for Disease Control and Prevention, researchers said
they had been detecting increases in the levels of drug-resistant
bacteria found in people with gastrointestinal illness from the
microbes _Salmonella_ and _Campylobacter_, which are most commonly
contracted from contaminated meat or eggs.
Last May, a team from the Centers for Disease Control and Prevention
[CDC] reported in the New England Journal of Medicine that the
prevalence of a _Salmonella_ strain resistant to five different
antibiotics increased from 0.6 percent of all specimens from around
country tested by the centers in 1980 to 34 percent in 1996.
Dr. Fred Angulo, a medical epidemiologist in the foodborne and
diarrheal disease branch at the CDC, said that similarly, drug
resistance in _Campylobacter_ bacteria rose from zero in 1991 to 13
percent in 1997 and 14 percent in 1998. He said epidemiologists were
"alarmed" by the _Campylobacter_ figures, because the resistance is to
fluoroquinolones, the very class of drug that the FDA is trying
hardest to preserve.
Angulo said he and his colleagues blamed much of the increase in
fluoroquinolone resistance on the FDA's approval of the drugs to treat
a respiratory infection in chickens in 1995. It was an approval the
CDC opposed, because it would lead to extensive use of the drugs on
A recent study, scheduled to appear in the New England Journal of
Medicine, was cited as offering strong evidence that people pick up
drug-resistant bacteria from chickens. In that study, researchers at
the state Health Department in Minnesota found that fluoroquinolone
resistant _Campylobacter_ had increased from 1.3 percent of cases in
1992 to 10.2 percent in 1998. The sharpest rise began in 1996, a year
after fluoroquinolones were approved for chickens.
Dr. Michael Osterholm, the former state epidemiologist in Minnesota,
said the health department also found _Campylobacter_ in 88 percent of
the chickens they bought in supermarkets in Minneapolis and St. Paul.
Twenty percent of the chickens had a resistant strain.
Osterholm said healthy people recover from _Campylobacter_, often
without even being treated. But in patients whose immunity has been
lowered by illness, AIDS or treatment for cancer, the infection could
be deadly. The proportion of society in that vulnerable category is
increasing, because of the aging population. "One of the things we're
beginning to understand is that we'll see a major change in the
implications of foodborne disease in our population. As we get a
little older, it has a much more serious implication."
Given the widespread availability of antibiotics on farms and the long
entrenched habit of using them, Angulo said regulation alone probably
would not bring about the changes that are needed, adding, "People
would have to accept that there is a problem. Many don't. It's a
societal change, and we have the same problems in human medicine."
Many people, he added, demand antibiotics for viral infections and
other problems that the drugs cannot help.
Angulo was quoted "The way we will make major progress, unfortunately,
is when there is continuing emergence of treatment problems, not just
in humans, but when these drugs don't work in sick animals. As that
increases, the realization might come."
Michele Gale-Sinex, communications manager
Center for Integrated Ag Systems
UW-Madison College of Ag and Life Sciences
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