April 25, 2011

Study on Drug-Resistant Staph and Store-Bought Meat: What Most News Reports Are Missing

Ralph Loglisci

Ralph Loglisci

Food and Health Policy Writer

Staphylococcus aureus, Image Courtesy: CDC

Staphylococcus aureus, Image Courtesy: CDC

According to a recently published nationwide study of grocery store meats, the next time you handle a piece of meat or poultry bought at your local supermarket there is nearly a 50 percent chance that it will be carrying drug-resistant Staphylococcus aureus (Staph). The Translational Genomics Research Institute study determined that the majority of those bacteria are likely resistant to several classes of antibiotics. Antibiotic-resistant strains of Staph are to blame for a host of illnesses, ranging from simple skin infections to life-threatening diseases, such as pneumonia and sepsis. Staph infects an estimated 500,000 patients in U.S. hospitals annually and more deathsdeaths are blamed on Methicillin-resistant Staphylococcus aureus (MRSA)infections every year than HIV/AIDS. Infectious disease experts warn the consequences of rendering antibiotics useless would be disastrous to modern medicine, which depends on antibiotics for everything from organ transplant surgeries and cancer therapies to the care of patients with trauma or battlefield injuries.

The frequency of detection of resistant bacteria on meat purchased in grocery stores is alarming.  Despite this, most of the news coverage we’ve seen this week misses a key message that can be gleaned from the conclusions of the study. The study does not point directly to new or heightened food-safety risks to the consumer, rather, it serves as verification that one of human medicine’s strongest safeguards against disease is quickly losing its efficacy, in part due to inappropriate use of antibiotics in the industrial food animal production system.

Reports that the meat and poultry we bring into our homes everyday to eat are contaminated with bacteria that can make us sick are not revelatory.  In fact, the government has been warning us for decades that safe food handling and preparation in the kitchen is an effective strategy for mitigating the risks of foodborne illness. While the idea that multidrug-resistant Staph could easily drip off a piece of raw meat onto our countertops is not a reassuring thought, the truth is they’ve probably been there for quite some time. Now that we know the drug-resistant Staph are there, it is critical to determine whether their presence have been affecting public health all along.

One critical message from the study is that most of these drug-resistant Staph had unique genetic signatures, which would suggest that they derive from animal production sites.  Lance Price, Ph.D., the lead author of the study and a former Center for a Livable Future (CLF) fellow, tells us that the study, “showed that chicken, turkey, beef and pork all had different DNA fingerprints for the different Staph, which is indicative of animals being the main source. So, when you see resistance, that’s a result of antibiotic use on the farm.”

The food animal industry is responsible for the majority of domestic antibiotic use. Using new data from the U.S Food and Drug Administration, the CLF determined 80% of the antibiotics available for both people and animals were sold for use in livestock and poultry. The majority of these antibiotics are administered to food animals routinely in low-doses to promote growth and purportedly to prevent disease stemming from overcrowded unsanitary conditions. The science to support the effectiveness of low-dose antibiotics for disease prevention is lacking, however, the overwhelming evidence that shows it is leading to the selection for the promotion of resistant bacteria is not. This unwise practice opens new pathways for antibiotic-resistant bacteria to be mobilized into the environment.

These resistant bacteria are not only finding their way onto the meat that we buy- they are also infecting food animal production site workers and people who live and go to school in communities near these production facilities. Consumers can reduce their risk of exposure to these resistant pathogens by taking precautions when they handle uncooked meats, or elect not to eat them altogether.  Unfortunately, the same is not true for workers and residents of communities near food animal production facilities and may be exposed to air, water, soils, or other media contaminated with these bacteria.  Numerous CLF-supported research projects have demonstrated that these drug-resistant bacteria can easily find their way out into the environment. Some transport pathways are less obvious, but still have the potential to increase infection risks to surrounding communities; one study confirmed flies can carry drug-resistant bacteria reaching communities miles away from facilities that routinely administer antibiotics to their animals, and another demonstrated that food animal transport trucks can serve as a means to distribute animal-originated resistant microorganisms into the environment.

It is important to recognize the social justice issues stemming from the use of antibiotics in food animal production.  In the majority of cases, the people operating and working in food animal production facilities are not responsible for the decision to use antibiotics to raise animals. These decisions are made by companies, or integrators, that contract with food animal growers to house and feed their animals. This misguided practice places the health of these contract growers, their workers, and surrounding communities at heightened risk; these risks are far greater than those faced by the general public as a result of the presence of resistant bacteria on meat.

Food animal industry groups and trade associations often claim drug-resistant bacteria that originate from farms do not pose risks to animal production workers, agricultural communities and the general public. Price bristles when he hears that claim. “I would say that they are basing that on zero data,” he says. “What this shows is that there is a risk, now we need to quantify it. This should serve as an alarm, and really begs for changes in the way that we produce our food animals in this country.”

-Ralph Loglisci

-Keeve Nachman, PhD, MHS

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