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  • From: Norma Sutton <sweetspringfarm@gmail.com>
  • To: Healthy soil and sustainable growing <livingontheland@lists.ibiblio.org>
  • Subject: Re: [Livingontheland] troubling potential source of resistant pathogens: the American farm
  • Date: Sat, 20 Jun 2009 20:37:46 -0400




Farmacology
http://www.cornucopia.org/2009/06/farmacology/#more-1510
Johns Hopkins researchers are investigating a troubling potential source of
resistant pathogens: the American farm

Johns Hopkins Magazine
By Dale Keiger

Ellen Silbergeld, Eng ‘72 (PhD), recalls that she did not want to go to
the seminar. She was a professor of epidemiology at the University of
Maryland School of Medicine in 1999 when her department’s chairman needed
an audience for the seminar’s presenter, a candidate for a faculty
position. Silbergeld recalls the chairman saying, “Please, just sit in
the room. You can come to lunch.” So she sat in the room, and something
caught her attention. The seminar was on hospital-acquired infections, but
the presenter mentioned in passing that some drug-resistant infections came
from food.

That seemed odd. Silbergeld knew you could pick up Salmonella from, say,
tainted chicken salad. But how would that Salmonella have become resistant
to antibiotics? She turned to a colleague and asked. Because, he said,
factory chicken farms routinely feed antibiotics to their flocks, to
accelerate growth, and the drugs generate resistance.

Ten years later, Silbergeld, now a professor of environmental health
sciences at the Bloomberg School of Public Health, is one of several
researchers at Johns Hopkins and around the world assembling evidence that
the industrial farming of chickens, pigs, and cattle is cultivating more
than poultry and livestock — it’s cultivating bacteria that medicine is
losing the ability to fight. Antimicrobial drugs, including antibiotics
like penicillin, ciprofloxacin, and methicillin, kill pathogenic bacteria.
But they simultaneously drive the resistance that is bacteria’s defense,
especially when administered in low, subtherapeutic doses. Scientists
estimate that 50 percent to 80 percent of all antimicrobials in the United
States are not used by doctors to treat sick people or animals but are
added to farm animal feed, mostly in such subtherapeutic dosages. Public
health researchers like Silbergeld are convinced that this nontherapeutic
use of antimicrobials is building dangerous genetic reservoirs of
resistance. If they are right, industrial agriculture is fostering and
dispersing drug-resistant bacteria that impair medicine’s ability to
protect the public from them.

The United States Department of Agriculture (USDA) estimates that livestock
and poultry produce 335 million tons of manure per year, which is one way
resistant pathogens get out of animals and into the environment. That’s
40 times as much fecal waste as humans produce annually. Farms use it for
fertilizer and collect it in sheds and manure lagoons, but those
containment measures do not prevent infectious microbes from getting into
the air, soil, and water. They can be transported off the farms by the
animals themselves, houseflies, farm trucks, and farm workers, and by
spreading manure on other fields. Out in the environment, they form a sort
of bank of genetic material that enables the spread of resistance.

Kellogg Schwab, director of the Johns Hopkins Center for Water and Health,
refers to a typical pig farm manure lagoon that he sampled. “There were
10 million E. coli per liter [of sampled waste]. Ten million. And you have
a hundred million liters in some of those pits. So you can have trillions
of bacteria present, of which 89 percent are resistant to drugs. That’s a
massive amount that in a rain event can contaminate the environment.”

He adds, “This development of drug resistance scares the hell out of me.
If we continue on and we lose the ability to fight these microorganisms, a
robust, healthy individual has a chance of dying, where before we would be
able to prevent that death.” Schwab says that if he tried, he could not
build a better incubator of resistant pathogens than a factory farm. He,
Silbergeld, and others assert that the level of danger has yet to be widely
acknowledged. Says Schwab, “It’s not appreciated until it’s your
mother, or your son, or you trying to fight off an infection that will not
go away because the last mechanism to fight it has been usurped by someone
putting it into a pig or a chicken.”

Industrial agriculture, known variously as factory farming,
concentrated-animal feeding operations (CAFOs), and industrial farm animal
production (IFAP), has produced an abundance of affordable steaks, pork
chops, and broilers for grocery shelves over the last 65 years or so. It
grew out of chicken farms on the Delmarva Peninsula, Midwestern pork
processing plants, and cattle feedlots in Kansas and elsewhere. In 2008,
the Pew Charitable Trusts and the Bloomberg School produced a report titled
“Putting Meat on the Table: Industrial Farm Animal Production in
America,” that outlined how, after the conclusion of the Second World War
in 1945, farm mechanization and the Green Revolution’s program of genetic
selection, irrigation, and chemical fertilizers combined to produce grain,
soybean, and especially corn harvests of extraordinary abundance. With all
that available corn, if you could feed it to livestock, you didn’t need
to raise animals in pastures. You could concentrate them in barns or
feedlots and raise far more animals on far less land.

Meanwhile, starting with mechanized hog slaughterhouses and Delmarva
chicken farms, canny entrepreneurs began to figure out how to take
traditional animal husbandry — grazing cattle, rooting pigs, and chickens
pecking in a barnyard — and transform it into the industrial production
of protein, with the efficiencies and economies of scale of any
manufacturing industry. They also grasped the entrepreneurial advantages of
vertical integration. On Maryland’s Eastern Shore, Arthur W. Perdue left
his job as a railroad agent in 1920 to sell eggs. By the 1940s, the company
he founded began moving into the production of broilers. Arthur’s son,
Frank, took over the company in 1950 and invested in hatcheries, soybean
refineries, feed mills, and processing plants, launching the company on a
course to become a modern integrated farming operation. The concept was
simple: If Perdue owned the hatchery, the feed production, and the
processing plants, it could gain significant efficiencies, control its
costs, establish the steady, predictable production of raw materials, and
grow into a very large company with control of a significant share of the
market. According to Perdue, by 2007 it was processing 633 million chickens
per year and had total sales of $4.1 billion.

In July 1946, the Journal of Biological Chemistry published a research
paper out of the University of Wisconsin that detailed the results of
feeding three antimicrobials to chickens. The summary included a crucial
sentence: “Sulfasuxidine and streptomycin singly or in combination lead
to increased growth responses in chicks receiving our basal diet
supplemented with adequate amounts of folic acid.” That is, feeding
antimicrobials to chickens made them grow faster. Agribusiness, eager to
increase profits by minimizing how long it took to get a chicken breast or
pork roast from the farm to your dinner table, was about to become a major
customer for pharmaceutical products.

How major is disputed. In 1999, the Animal Health Institute (AHI), a trade
association representing 17 companies including Abbott Laboratories, Bayer,
Dow AgroSciences, Monsanto Company, and Pfizer, released a study that
estimated 17.8 million pounds of antimicrobials were used each year, for
all purposes and for all animals, including pets. For its 2001 report,
“Hogging It: Estimates of Antimicrobial Abuse in Livestock,” the Union
of Concerned Scientists (UCS) mined data on antimicrobial production and
concluded that AHI’s figures were much too low; UCS estimated that 24.6
million pounds are applied annually just for nontherapeutic purposes —
primarily growth promotion — in only three types of farm animals —
cattle, swine, and poultry. A 2003 paper published by Poultry Science
questioned both figures and stated, “No unbiased estimates of
antimicrobial use in animals exist at the present time.” Any estimate
becomes problematic as soon as one understands what UCS called “the
dismal absence of information” about both production and consumption of
antimicrobials. The federal government does not collect figures on how much
product comes out of the pharmaceutical industry, nor does it require
agricultural corporations to disclose how much they use.

In his 1945 Nobel Prize address, Alexander Fleming warned that it was easy
to produce microbes resistant to his discovery, penicillin: Simply expose
them to concentrations of the drug insufficient to kill them. Possibly the
first warning that antibiotics could produce drug-resistant pathogens in
poultry came as far back as 1951, when two bacteriologists at the
University of California, Davis named Mortimer P. Starr and Donald M.
Reynolds published a paper that noted in its summary: “The use of
streptomycin as a growth-promoting supplement in turkey poults results in
the appearance within three days of streptomycin-resistant coliform
bacteria.” But little apparent attention was paid to Starr and Reynolds,
or to Fleming. During ensuing decades, tens of millions of pounds of
tetracycline, penicillin, and other antibiotics were fed to animals on
American and European farms. In some cases, the drugs were used to treat
sick animals, in amounts that killed the bacteria. But most were fed to
cattle, pigs, turkeys, and chickens in exactly the subtherapeutic dosages
that Fleming warned would only make bacteria stronger.

After Silbergeld first heard about farmers feeding antibiotic additives to
broiler chickens, she asked two faculty members in Maryland’s poultry
science program to show her the school’s chicken barns on the Eastern
Shore. As soon as she walked into one, she thought, “This is really
serious.” There were thousands of chickens crowded in tight confines. She
says, “They are raised — how can I put this nicely? — they are raised
on top of their own shit. They walk around on litter, which is sawdust or
some kind of substrate, covered in feces. It’s the most unhygienic thing
you can imagine.” The air was hot and full of dust. Periodic partial
removal of litter from the barns created large piles of manure that were
stored outside with minimal containment measures. Any farm worker laboring
in such a facility had to be exposed to microbes, Silbergeld thought. If
the chickens had been fed antibiotics, then some of those microbes had to
be drug resistant.

While still at the University of Maryland, Silbergeld decided her first
farm project would be to study whether poultry workers and people in farm
communities were at risk of carrying the same strains of drug-resistant
bacteria found in chickens, a study she finished after she came to Johns
Hopkins in 2001. In Eastern Shore communities like Pocomoke City, Princess
Anne, Smyrna, and Salisbury, she enrolled three groups of subjects: workers
whose job was to catch chickens in the barns to load onto trucks for
transport to processing plants, chicken hangers who attached live birds to
the mechanized line at the plant, and community residents who did not work
in the industry but lived near it. She found that 41 percent of the chicken
catchers had been colonized by Campylobacter jejuni, which is commensal in
poultry — it derives benefit from the chicken without harming it — but
pathogenic in people, where it’s the second-leading cause of
gastrointestinal disease in the United States. Among the workers at the
poultry processing plant, the rate of colonization was 63 percent. Of the
nine people who lived near but did not work in the industry, 100 percent
had been colonized.

Carole and Frank Morison became contract growers for Perdue 22 years ago on
a farm near Pocomoke City. Drive down U.S. 13 toward the Morisons’ place
and you will see the land become flat as a plank and ideal for farming. The
roads around Pocomoke City lead past one chicken farm after another, each
marked by a sign displaying the name of the farm and the company that
provides its chickens: Aydelotte Farm — Tyson; Sheep House Farm —
Tyson; Poor Boy Farm — Mountaire; Meatball Farm — Tyson. You will see
long, closed barns vented by giant fans. What you will not see anywhere is
a chicken. They are there, hundreds of thousands of them, but they are all
enclosed in the barns. From the road, you don’t even hear a cluck.

In 1987, Frank Morison, a second-generation Eastern Shore farmer,
approached Perdue to get into the chicken business. There was no such thing
as becoming a poultry farmer by simply buying some chickens to raise. If
you did not have a contract with a processor like Perdue, Tyson, or
Mountaire, you would have great difficulty buying chicks, buying feed, or
finding a place to sell your broilers after they’d reached market weight.
Basically, Morison says, anything but doing business with a big processor
was impossible. So Morison borrowed $200,000 against his house and his land
to build a pair of 20,000-square-foot barns. Perdue specified every aspect
of the construction.

After the barns were built, one day a truck pulled up to the farm and
delivered 54,400 chicks, plus the feed that Morison, by stipulation of his
contract with Perdue, was to feed them. Perdue dictated the number and type
of chicks, which they owned and merely consigned to Morison; the amount,
price, and composition of feed; and the date, 51 to 53 days later, on which
workers would be back to pick up the grown birds for processing. Whenever
the chickens from his farm were processed, Perdue informed Morison how much
they weighed, how much it would pay him per pound, and how much the company
was deducting for feed and other supplies it had required him to use.
Morison says in the end he typically cleared 2 percent to 3 percent per
flock, not counting his labor.

Neither federal nor state regulations require processors to divulge the
exact contents of the feed they furnish their growers; the government
allows the processors to treat that information as proprietary. So the
Morisons say they never knew the quantity of heavy metals like selenium,
copper, arsenic, and zinc, or the amount of drugs like tetracycline and
penicillin, that were going into, and eventually coming out of, the birds
on their farm. But they began to notice how often their farm neighbors
complained of not feeling well. Carole says, “There are a lot of
sarcastic jokes among farmers. You’d be talking to someone and he’d
say, ‘Yeah, I’m not feeling too good this week, I got vaccinated along
with the chickens.’ It was just a routine thing. But people were having
‘the bug’ too often. Kind of like flu symptoms: achy body, upset
stomach, bronchial issues.” The Morisons exhibited the same symptoms.
Around 1995, Carole recalls, she became intolerant of antibiotics, which
began to give her hives, upset her stomach, and worsen her asthma. “To
this day, I still have problems.”

Last July, the Morisons got out of the chicken business. They say that
Perdue had notified them that to continue growing for the company, they
would need to make $150,000 worth of upgrades to their facilities. They
balked at the expense and decided they’d had enough of farming. They are
now employed by the Socially Responsible Agriculture Project, working to
link farmers all over the Chesapeake Bay watershed and create local markets
and local distribution systems. “Going back to raising food the way it
used to be raised,” Carole says.

At Hopkins, Silbergeld decided to concentrate her initial research on the
occupational health aspects of factory farming. With five co-authors from
the Bloomberg School and the School of Medicine, she published the first
U.S.-based study of poultry workers colonized by resistant microbes,
reporting that 50 percent of surveyed workers carried E. coli that was
resistant to the antimicrobial gentamicin, compared to only 3 percent of
community members who did not work with poultry. She studied the
association between occupational contact with live chickens, Campylobacter
jejuni, and peripheral neuropathy, and found a significantly elevated
presence of anti-Campylobacter antibodies in poultry workers, indicating
colonization; many of those workers also reported symptoms of neurological
disorders associated with the pathogen.

Researchers at other institutions around the world reported similar
associations. At industrial poultry or swine farms, there were
drug-resistant bacteria colonizing farm workers and their families. In 2003
and 2004, Kellogg Schwab sampled the air at a factory farm that housed
3,000 hogs in two buildings. The samples contained enterococci, staph, and
streptococci, and 98 percent of the bacterial isolates were resistant to
two or more common antimicrobials. In a paper published in Environmental
Health Perspectives, Schwab suggested that one way bacteria could travel
from animals to humans was by workers breathing that air. In another study
from 2002 to 2004, Schwab sampled surface and ground water upgradient and
downgradient from a pig farm. He and his co-researchers found the
downgradient water — that is, water in the direction of flow from the pig
barns — contained 17 times as much enterococci, 11 times as much E. coli,
and 33 times as much fecal coliforms as water upgradient from the facility.
The downgradient pathogens also were much more likely to be antibiotic
resistant.

One day, a Bloomberg School colleague down the hall from Silbergeld came
back from a weekend on the Eastern Shore complaining about how disgusting
she’d found having to drive behind a truck hauling chickens to a
processing plant. Silbergeld remarks, “When somebody says
‘disgusting,’ I say, ‘Wait a minute, there’s got to be something
going on here.’” She and two of her students, Ana Rule and Sean Evans,
designed what they called the “baby-you-can-drive-my-car” study. They
loaded passenger cars with sampling equipment, figured out that an
intersection on the Eastern Shore near the Virginia border would have a lot
of poultry trucks passing through on the way to Perdue and Tyson processing
plants, and drove to an adjacent shopping center parking lot. Whenever a
poultry truck stopped at the traffic light, the researchers would slide in
behind and follow it to the processors. Afterward, they sampled the air
inside the car, as well as the car’s exterior door handles and an
unopened soda can they had placed in the car’s cup holder. They found
that the air in the car and both surfaces showed increased levels of
enterococci after they’d driven behind the chicken trucks. Samples
obtained before the car followed the trucks contained no resistant
enterococci; a quarter of the bacteria isolated after the trucks showed
resistance to antimicrobials, including tetracycline, erythromycin, and
streptomycin.

This was not the only study that involved a car. Jay Graham, formerly one
of Silbergeld’s grad students and now at the United States Agency for
International Development, was studying issues of waste disposal on the
Eastern Shore. He noticed that every time he came back to Baltimore, his
car was covered with flies, and this led him to wonder if flies might be
capable of dispersing resistant bacteria from factory farms. Graham told
Silbergeld that he wanted to do a study. “I said, ‘That’s OK, so long
as you don’t bring any flies here.’ The next thing I knew, we had these
two big jars full of flies in the lab and I thought, ‘So much for
that.’” Graham had trapped the flies near poultry farms on the Eastern
Shore and found resistant staph and enterococci on them. He analyzed both
pathogens for drug-resistance genes and found matches in bacteria taken
from the flies and bacteria taken from farm litter, a strong indication
that flies are a potential source of exposure to the resistant bacteria
lurking in farm wastes.

Scientists know that resistant pathogens can travel from farms by air,
water, bird, housefly, chicken truck, or manure spreader, but they do not
yet have a good answer to how far they can travel or how long they can
remain viable. Just because a researcher detects drug-resistant staph in an
air sample doesn’t prove it’s likely to make anyone sick. But one means
of transmission that can cover significant distances is person-to-person
— a farm worker, for example, picks up bacteria in a chicken barn and
passes it to a family member, who passes it to a member of the community,
who brings it into a health clinic or hospital, where it takes up residence
and begins causing antibiotic-resistant infections in surgical patients and
the immuno-compromised. For years, scientists, physicians, and the public
have regarded increasingly prevalent drug-resistant infections as a
hospital problem (see “Bugs vs. Drugs,” Johns Hopkins Magazine,
February 2008). That’s where dangerous microbes like vancomycin-resistant
enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA)
lurk and spread. But then hospitals began to report more and more people
who had never been near a health care facility coming through their doors
already colonized by resistant bacteria. Where were people picking up bugs
like MRSA, which now kills more than 20,000 people each year, more people
than die from AIDS?

About three years ago, Silbergeld began thinking about MRSA and industrial
agriculture. She was not the only one. In November 2006, Dutch researchers
reported the case of a young mother treated for mastitis in October 2004.
Cultures taken by her general practitioner revealed MRSA, which was then
found in her husband and baby daughter. Her husband was a farmer with 8,000
pigs, and when researchers tested 10 chosen at random from the farm, they
found genetically identical MRSA in eight of them, and the same bug in
three other workers from the farm. In another case, also from Holland, a
63-year-old woman had been admitted to a hospital with MRSA-caused
endocarditis. When scientists typed her infection, they found it did not
match hospital-acquired strains of MRSA, nor the strains causing
community-acquired MRSA skin infections in the United States. What it did
match was MRSA isolated from Dutch pig farms. Yet another study from
Holland found the rate of MRSA colonization among pig farmers to be 760
times that of the general public. A year later, Canadian research published
in Veterinary Microbiology was the first to find MRSA in North American
pigs and pig farmers; scientists studied farms in Ontario and found MRSA in
25 percent of tested pigs, and 20 percent of workers from farms that had
colonized animals. On farms that were free of colonized pigs, there were no
human cases. Finally, last January, a study out of the University of Iowa
sampled 299 pigs and 20 workers from two farms in Iowa and Illinois. The
researchers found MRSA in 49 percent of the animals and 45 percent of the
people. This was the first such finding in the United States, and the
strain, ST398, was identical to what had been found in Canada and Holland.

Silbergeld has begun a MRSA study of her own, trying to establish
attributable risk — that is, how much exposure to industrial agriculture
contributes to the overall prevalence of MRSA in people coming into
hospitals. The crux of the matter, she believes, comes down to molecular
biology. Bacteria have a remarkable capability for sharing genes, through
what is known as horizontal gene transfer. The old view of resistance was
Darwinian: In the presence of antibiotics, a mutation would be naturally
selected if the mutated gene helped a microbe survive application of the
drugs. “That underestimates the brilliance of microbes,” Silbergeld
says. Molecular biologists now understand that within a microbial
community, one microbe can acquire genetic material from another microbe,
even a microbe of a much different type, then incorporate it in its own
genome and thus acquire resistance to an antibiotic it has not yet even
encountered. It’s as if bacteria are capable of downloading resistance
from a gene database.

What’s more, microbes carry genes in what are called resistance
cassettes, which can be thought of as kits that contain a variety of genes
for fighting off different drugs. So, a germ resistant to tetracycline may
have a resistance cassette that contains not only the gene for fighting off
that drug, but genes resistant to other drugs, as well. The result? A
person could be colonized by a tetracycline-resistant germ that does her no
harm, but lurks in her system and contains, in its cassette, resistance to
methicillin. If this unlucky person then acquires a simple staph infection,
and that staph encounters the first microbe and taps its resistance
cassette, her routine staph infection has now become MRSA and she could be
in real trouble. Silbergeld’s biggest concern is that factory farms are
building reservoirs of these resistance cassettes in animals, in the
environment, and in humans.

The trade association for the Eastern Shore’s poultry producers is
Delmarva Poultry Industry, Inc. The day before Earth Day 2009, the headline
on DPI’s Web site read, “Every Day is Earth Day for Delmarva’s
Chicken Industry.” The agriculture industry argues that removing
antibiotics will result in more sick animals, that there is insufficient
data to prove that resistant pathogens from farms are making people sick,
and that there needs to be better drug-specific risk assessment. For its
part, Perdue states that it does not use antibiotics for growth promotion,
“nor do we use any antibiotics continuously for any reason,” according
to a statement on its Web site. In a 2006 USA Today story, Tyson’s chief
veterinarian said that his company had reduced its antibiotic use from
853,000 pounds in 1997 to 59,000 pounds in 2004, and now applied
antibiotics to less than 1 percent of its broilers. (A Perdue spokesperson
said the company would not consent to an interview for this story. Neither
Tyson nor DPI returned calls from Johns Hopkins Magazine.)

The May 2009 issue of For the Record, “straight talk about antibiotic
use,” published by Alpharma Animal Health, a division of King
Pharmaceuticals, cites four studies that state the risk of transmission of
drug-resistant pathogens from farm animals to humans is negligible, as
would be the benefit of withdrawing antibiotics such as virginiamycin from
agricultural use. Three of the studies were conducted by Cox Associates, a
consulting firm that does health-risk analysis for the USDA and for a
variety of corporations and industry associations, including the American
Petroleum Institute, the Chemical Manufacturer’s Association, Monsanto,
and Mobil Oil. One Cox study, published in Environment International, says
that “it appears very probable that such a withdrawal [of virginiamycin
from agricultural use] would cause many times more human illnesses than it
would prevent.” That study acknowledges use of a quantitative assessment
tool that was developed with financial support from AHI, the agricultural
pharmaceutical trade association.

Liz Wagstrom, assistant vice president of science and technology for the
National Pork Board, disputes the premise — she calls it “a kind of
urban legend” — that subtherapeutic dosages of antibiotics drive
resistance. She says, “When you go out looking for hard data, you can
find examples where that may be true, and you can find examples where
that’s not demonstrated. So the fact that subtherapeutic use is
automatically going to be more selective for resistance than any other use
of antibiotics — I’m not sure that I’m willing to say that that’s a
hard and fast rule.”

Wagstrom makes a similar argument in regard to MRSA: “There’s been a
lot of fingers pointed at the potential contribution of pigs to the U.S.
epidemic of MRSA, and it’s been based on very little data. I think it’s
been positioned to try to put fear in people about modern agricultural
practices, and that’s probably not scientifically justified.”

Defenders of industrial agriculture cite studies from Purdue University,
Ohio State University, and Iowa State University that found no proof
linking MRSA in pigs to the pathogen in humans, that pigs reared without
antibiotics are more likely to carry Salmonella and parasitic disease, and
that 96 percent of antibiotic resistance should be attributed to human, not
agricultural, use of drugs.

The National Pork Producers Council’s communications director, Dave
Warner, says, “We don’t believe we are the main cause of antibiotic
resistance. The American Veterinary Medicine Association says that on a
per-pound basis people and their pets use 10 times as much antibiotics as
livestock production does. Every bathroom and kitchen in America has
antibacterial soap in it.”

He adds, “We are not saying, ‘There is no connection, leave us
alone.’ We certainly are concerned about it. But I don’t think that use
of antibiotics in livestock ought to be singled out, and if we do something
about that all the problems are taken care of. But that’s probably an
easier problem to go after. There are only 67,000 pork producers [in the
U.S.]. How many doctors are out there? And how many people?”

The whole debate exasperates Silbergeld, who says, “These are feed
additives. It’s like using antibiotics as hair dye.” She adds, “We
have this practice of permitting the addition of almost any antibiotic that
you can think of to animal feed, for no therapeutic purpose, under
conditions that absolutely favor the rise of resistance. We have no
controls or management of the wastes. Our food safety system is a shambles.
This is a situation that is widely recognized by the World Health
Organization, the American Medical Association, and by others, and nothing
happens! It’s astounding to me!”

Silbergeld and Schwab support the use of drugs to treat sick animals but
believe all antibiotics should be banned from animal feeds. They have
followed the debate over cefquinome, a fourth-generation cephalosporin
antibiotic. A Delaware company, InterVet Inc., wants FDA approval to use
cefquinome to treat bovine respiratory disease. But the antibiotic is
chemically related to cefepime, one of the few remaining options for
treating deadly infections in cancer patients. Scientists fear that if
pathogens develop resistance to cefquinome, that resistance could quickly
ruin cefepime for human use. The American Medical Association, several
other health groups, and the FDA’s own advisory group have all urged the
agency to reject the drug for use on farm animals, but it has yet to do so.
Silbergeld is appalled.

“Sometimes I think we’re such a dumb species, we don’t deserve to
survive on this planet,” she says. “I mean, how many times do we have
to do this?”

Dale Keiger is associate editor of Johns Hopkins Magazine.

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