The superbug in your supermarket: Dangerous antibiotic-resistant microbes have been discovered in pork and other meat.

Published in Prevention magazine in August 2009.

About two years ago, dozens of workers at a large chicken hatchery in Arkansas began experiencing mysterious skin rashes, with painful lumps scattered over their hands, arms and legs. “They hurt real bad,” says Joyce Long, 47, a 30-year veteran of the hatchery, where until recently, workers handled eggs and chicks with bare hands. “When we went to the doctor and got cultured, he told us we had the worst kind of sickness—a superbug.” Its name, she learned, was MRSA, or methicillin-resistant Staphylococcus aureus. It gets its moniker because this version of the staph bacteria developed resistance to the antibiotics (including methicillin) that used to be effective against it, making it hard to treat, even lethal. According to the Centers for Disease Control, certain types of MRSA infections kill 18,000 Americans a year—more than die from AIDS.

Soon, co-workers at the nearby processing plant, where each day hundreds of thousands of chicken carcasses are prepped for sale, began finding the lumps. Dean Reeves, an 11-year plant employee, went to emergency room with an excruciating bump on her thigh that she thought was a spider bite. It wasn’t: She, too, had contracted MRSA. Since November 2007, Reeves, 50, and her husband, Bill, 46, who also works at the processing facility, have experienced relapses every single month. Even the safety glasses, gloves, and smocks workers wear—along with additional cleaning of the plant’s equipment instituted by its owner—aren’t enough to protect them from the pathogen, says Bill. “We work so fast we often stick ourselves with scissors or knives, and get blood slung on us from head to foot,” he explains. When a large swelling appeared over one of his eyes, he was told he might go blind; if the MRSA infection progressed to his brain, he’d die.

Did any food-safety or public-health agency test for MRSA in this plant’s chickens, which were then sold to the public and served on American dinner tables? Did any government organization investigate the source of the two-year-long outbreak? Calls to the USDA, the CDC, and the Arkansas Department of Health yielded a “no” to both questions; the poultry company that owns the operation did not respond to multiple requests for comment. Yet in recent years, studies have found MRSA in retail cuts of chicken, pork, beef, and other meats in the United States, Europe, and Asia.

Here, Prevention takes a closer look at what this means for you and your family: We investigate how MRSA has entered our food supply, with limited government response; we consider the massive use of antibiotics in agriculture and its role in creating resistant microbes like MRSA; and we evaluate the safety of our supermarket meat and offer expert advice to help you protect yourself.

Are you at risk?
You’ve probably heard of people contracting certain strains of MRSA in a hospital or health-care facility, where it causes many types of illness: post-surgical infections, pneumonia, toxic shock, bacteremia, and more. Other people encounter different strains of the microbe in community gathering places like gyms, where skin-to-skin contact occurs and items such as sports equipment are shared; this form causes skin infections that may become systemic and turn lethal.

Then in 2008, a new source of MRSA emerged: Researcher Tara Smith, PhD, a microbiology professor at the University of Iowa, discovered the microbe in large Midwestern hog farms. The strain—ST398—had never before been seen in the United States; Smith found it in 45% of farmers and 49% of pigs in the farms she studied.

This startling report implies a close connection between animal and human health, yet even after widespread publicity and much official hand-wringing, we don’t even have a comprehensive MRSA inspection process in place, let alone a remedy to fix our sick meat-production system.

Though you may not have the close contact with meat that a processing-plant worker has, scientists warn there is reason for concern: If you’re like most Americans, you handle raw meat daily—as you bread chicken cutlets, trim fat from pork chops, or form chopped beef into hamburgers. Cooking kills the microbe, but you don’t have to eat it to catch it. MRSA thrives on your skin, so you can contract it by merely touching infected raw meat when you have a cut or scrape on your hands, explains Stuart Levy, MD, Tufts University microbiology professor and president of the Alliance for the Prudent Use of Antibiotics. MRSA also flourishes in nasal passages, so even absentmindedly touching your nose before washing your hands gives the pathogen another pathway into your body, adds Smith.

In the past year, researchers have begun taking a closer look at meat sold to the public: Scientists at Louisiana State University Agricultural Center tested 120 cuts of locally purchased meat and found MRSA in 4% of the pork and 1% of the beef. A University of Maryland scientist found the drug-resistant pathogen in 1 of 300 pork samples from the Washington, D.C. area. And a study in Canada (from which we import tons of meat annually, according to the National Pork Board) found MRSA in 10% of 212 pork samples. 

Think of the billions of servings of meat available to the public at any one time, says Steven Roach, director of public health programs of Food Animal Concerns Trust and a food-safety advocate. The USDA puts the total U.S. consumption of all meat at 27 million tons per year. “When you consider the tiny number of samples in the meat studies, the fact that they found any contamination at all is amazing,” says Roach. 

In some cases, the MRSA-tainted meat probably came from infected animals; in other situations, already-infected humans or equipment could have contaminated the meat while it was being processed. Regardless of where the microbe originated, even just a small proportion of contaminated meat could mean a tremendous amount of MRSA out there, says Roach. Extensive research in Europe found ST398 in most species of food animals and their meat. “We need more US research to figure out what’s going on,” says Roach.

MRSA is so common in the United States that it accounts for more than half of all soft-tissue and skin infections in ERs. The CDC estimates that invasive MRSA infections (those that have entered the bloodstream, including pneumonia, bacteremia, and more) number about 94,000 a year. Even more troubling, if you add up other types of illnesses MRSA can cause, including in-patient skin infections, the total is 8 to 11 times higher, according to a study by epidemiologist William Jarvis, MD, for the Association of Professionals in Infection Control and Epidemiology (APIC). The number is high, but also rising. From 1999 to 2005, MRSA-related hospitalizations increased 10-fold.

Individuals who contract MRSA need ever-more-powerful medications. “Staph-related infections, which once responded to an oral course of penicillin, have become serious illnesses that can require hospitalization and stronger drugs,” says Georges C. Benjamin, MD, director of the American Public Health Association. For Long, from the Arkansas chicken hatchery, doctors prescribed vancomycin, the antibiotic of last resort for MRSA. Though the swellings would subside for awhile, they’d soon reappear. She also experienced prolonged side effects. “I was tired, got headaches, and felt sick to my stomach,” she says. “And every time I went back to work, I got it again, for a total of 10 times. My doctor says I’ll never be free of it.”

Animal pharm
Scientists are beginning to examine the relationship between antibiotic use in industrial agriculture and the MRSA. “We know that antibiotic overuse in humans caused ordinary staph to become resistant, and that the large amounts used by agriculture caused other bacteria—E.coli, salmonella, and more—to develop resistance,” says Levy. “Now we’re looking at MRSA.”

It’s an important endeavor, because industrial agriculture is the country’s largest antibiotic user. The Union of Concerned Scientists estimates animals consume nearly 70% of these medications—perhaps 24 million pounds a year. The drugs compensate for unsanitary conditions in the country’s 12,000-some factory farms—often called contained-animal feeding operations, or CAFOs—where about half our meat is produced nowadays. Long gone are many of yesteryear’s family farms, with chickens pecking in the yard and animals grazing on pastureland, says Robert Martin, senior officer of the Pew Environment Group. “Instead, animals are packed into cramped quarters, never going outdoors, living in their own waste.” A swine factory farm can have hundreds of thousands of hogs in several barns; a large poultry operation may have millions of chickens. “As a result,” says Martin, “you need to suppress infection.”

The amounts of antibiotics used in CAFOs are high, but also important, some of the drugs are critical for curing human illnesses, according to Martin. Read the ingredient list for pre-mixed animal feed, and you’ll see names you recognize: tetracycline, penicillin, cephalosporin (which you may know as Keflex), and flouroquinolone (Cipro is a familiar brand). You can also buy a 50-pound bag of antibiotics at a feed store to add to your animals’ chow, confirms Amy Meyer, executive director of the Missouri Farmers Union. No prescription necessary.

The antibiotics given to CAFO animals do more than kill infection. For reasons that are not understood, small continual doses of medication stimulate growth, getting the animals to market weight more quickly. The minimal amounts don’t kill all the microbes in the animals’ systems, though, says David Wallinga, MD, director of the Food and Health Program of the Institute of Agriculture and Trade Policy. Instead, the drugs eliminate weaker bugs, leaving behind the tougher, resistant ones. This is just what your doctor wants to prevent when he tells you to take all of your antibiotic prescription within the established time. Smith, the researcher from Iowa, calls the giant operations “reservoirs” of antibiotic resistance.

In the areas surrounding CAFOs, doctors see first hand how MRSA impacts the community. Philip McClure, MD, lives and works in Trenton, Missouri, home to many hog farms. MRSA infections have risen in the past five years, as the number of pigs has grown, says McClure, who estimates he treats a MRSA-related skin problem every month. “If I’m suspicious, I’ll always culture for it,” says McClure. And it’s not just CAFO workers who get MRSA, but others as well.

That may be because MRSA spreads in what Smith calls an “insidious” way. You can contract it without showing any symptoms for perhaps years. Meanwhile, you can infect others without knowing it, even simply by sharing a towel. Kim Hudson, 44, a former hog CAFO worker in Oklahoma, fears she did just that: In 2007, her husband and teenage daughter went to the ER with skin infections that were determined to be MRSA. “I remembered my co-workers telling me about painful lumps they had and realized I could have become a carrier,” says Hudson. “I was so angry.” Hudson, who then quit the CAFO job, was never tested at the time, so she’ll never know if she unwittingly transmitted MRSA to her family.

Concerned about the risks of factory farming, the American Public Health Association (AHPA) examined peer-reviewed research and in 2007 reported that CAFOs caused many problems: increasing antibiotic resistance; air, land, and water pollution; disease outbreaks and high rates of respiratory illnesses in communities where they are sited; and evidence that factory-farmed meat offers poor nutrition. The AHPA has since called for a moratorium on building new CAFOs until we better understand how they contribute to these matters.

Whos watching out for you?
Until recently, the CDC has acknowledged the presence of MRSA in meat but downplayed the danger. In a 2008 letter to the House Committee on Agriculture, then-CDC director Julie Louise Gerberding, MD, said that foodborne transmission of MRSA is “possible” but, if it happens, “likely accounts for a very small proportion of human infections in the United States.” Liz Wagstrom, DVM, spokesperson for the National Pork Board, agrees with the CDC, saying that this kind of transmission would be “rare,” says. Neither organization could provide an estimate when queried by Prevention, but considering the high numbers of MRSA infections—perhaps a million annually, according to APIC research—even a tiny percentage could be a lot of people.

One reason the CDC and the National Pork Board must guess about transmission rates—and why we don’t know exactly how many MRSA-related infection occur annually—is that the federal government doesn’t collect data on MRSA outbreaks, says Karen Steuer, director of government operations for the Pew Environment Group. And according to the Government Accountability Office (GAO), the nonpartisan investigative arm of Congress, there’s little testing for foodborne bacteria on farms—and none for MRSA. The National Antibiotic Resistance Monitoring System tests just 40 retail cuts of meat monthly for four drug-resistant bacteria—and that does not include MRSA.

“As a result of these gaps in data, we’re in the dark,” says Steuer. Without farm-to-fork surveillance, it’s difficult to connect problems at a certain farm or meat-processing facility to MRSA outbreaks. “If we don’t fix this problem, mortality rates will go much higher,” she says. “We have an impending crisis.” •



CURES FOR SICK MEAT
Several ideas are on the table. Keep Antibiotics Working, a large national coalition of health and science organizations, calls for more federally funded and executed research to find out exactly why MRSA is appearing in our meat and how to get rid of it. Representative Rosa DeLauro (D.-CT), long-time food-safety advocate, suggests giving all supervision of food—now split up among many agencies—to just one, which may improve oversight and close the information gaps.

Representative Louise Slaughter, MPH (D.-NY), reportedly Congress’s only microbiologist, wants to trim industrial agriculture’s use of antibiotics to just those drugs that are not essential for human use. Research, including studies by Levy, show this would cause antibiotic resistance to drop in a wide range of bacteria, though how it would effect MRSA is not yet known. Earlier this year Slaughter introduced the Preservation of Antibiotics for Medical Treatment Act of 2009 (PAMTA) in the House of Representatives, and Senator Edward Kennedy (D.-MA) submitted a related bill in the Senate. PAMTA has broad support, from The American Medical Association to the Infectious Diseases Society of America, the American Academy of Pediatrics, and more than 350 other groups.

Bottom line, says Roach, of Food Animal Concerns Trust, we must look for comprehensive solutions that involve lower antibiotic use in humans as well as animals. “For those who raise livestock, it means thinking of ways to raise animals that prevent them from getting sick in the first place,” he says.

And we must move quickly, according to Slaughter. “As a scientist, mother, and grandmother, I cannot overstate the urgency of this problem. At the grocery store, we should be able to buy our food without worrying about exposing our family to potentially deadly bacteria that no longer respond to medical treatment.”
   
Consumers may worry that curbing antibiotics will drive up the price of meat, The National Research Council says it will, but not by much—consumers might pay $1.2–2.5 billion more annually, or $4–$8 per person. Think of it this way: That’s the savings obtained by having one meatless meal per year.


BUY SAFER
Follow these guidelines to reduce the chances of MRSA contamination in your meat, says Polly Walker, MD, MPH, associate director of the Johns Hopkins Center for a Livable Future:
At the supermarket. Look for “USDA Certified Organic” on the label. That means the animals have not been fed antibiotics, hormones, or animal byproducts. Other labels, such as Antibiotic Free, are not verified by independent testing.
• Alternate sources. Log on to the Eat Well Guide, eatwellguide.org, a searchable online database of stores, restaurants, and farmers’ markets; enter your zip code and the item you’re seeking, such as organic meat, to find a local supplier.
• Other forms of protein. A study by Walker and others shows that eating excess protein from meat elevates risk for chronic illnesses, such as cardiovascular disease and some cancers. Substitute beans, lentils, tofu, and other plant protein sources for meat one day per week, advises Walker. For recipes and other information, go to meatlessmonday.com, a program of the Johns Hopkins Bloomberg School of Public Health. For more ideas, visit prevention.com/recipes.


COOK SAFER
You may not know if your meat contains an antibiotic-resistant pathogen, but you can protect yourself and your family: 
• Wash your hands. Use hot soapy water before you prep your meat, and again after. Never touch raw meat and then your nose, as MRSA thrives in nasal passages.
• Keep cuts covered. If you have scrapes or open wounds, cover them with water-resistant, sealing band-aids or use rubber gloves. MRSA and other pathogens can use the openings as entry points.
• Avoid cross-contamination. When finished handling meat, use hot, soapy water to clean surfaces and utensils that came in contact with it. This will help prevent other foods from becoming infected.
• Make it well done. To kill MRSA and other foodborne bacteria, cook meat to the proper temperature, testing with a meat thermometer to be sure it is done through. For well-done pork and beef, the internal temperature should be 170°; for well-done chicken, it’s 165°.

c. Stephanie Woodard.

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