The Health Threat
Scientists developed the first antibiotics, like sulfa and penicillin, six decades ago. Devastating diseases like pneumonia and tuberculosis, often fatal before, suddenly were treatable. From the beginning, bacteria steadily evolved resistance to these miracle cures. Due to widespread antibiotic overuse, however, the spread of resistance has intensified. Today, some bacterial strains are resistant to a number of previously effective drugs.
Resistant bacteria may cause longer illnesses and increase the risk of dying from infection. For some infections, only one or two medicines "of last resort" are now effective. For example:
- Staphylococcal bacteria are common causes of infection, including life-threatening infections such as toxic shock syndrome, and infections of the heart valves. In the U.S., nearly every strain of the bacteria Staphylococcus aureushas become resistant to treatment with penicillin. Many strains also are resistant to newer medicines related to the drug methicillin. Even vancomycin, which for years has been the only treatment uniformly effective against S. aureus, has been losing its effectiveness since 1997.
Campylobacter bacteria are the most common cause of bacterial food-borne illness, with over 2 million such cases of "food poisoning" annually. Most Campylobacter infections do not require treatment. But of those that do, one in six (18%) are resistant to a fluoroquinolone antibiotic, the treatment of choice for food poisoning. Ten years ago, such resistance was negligible.
While medical use of antibiotics is a major contributor to the emergence of antibiotic resistance, agricultural uses also pose a significant problem since they promote the development of resistant bacteria that can reach humans through several different pathways - directly via contaminated food or indirectly via environmental contamination.
U.S. meat producers routinely put low levels of antibiotics into feed given to non-sick animals, both to spur faster growth and to compensate for raising animals in the crowded industrial-scale conditions which now predominate in the US. Many of the 17 antibiotics used to promote livestock growth are identical or closely related to those used to treat sick people.
Antibiotic treatments of choice for humans also are being used to treat infections in food animals. In some cases there is direct evidence that this non-human use is compromising the medicine's effectiveness in people. In 1999, for example, an estimated 38,000 pounds of fluoroquinolone antibiotics were used to treat respiratory infections in poultry; fluoroquinolones are the empiric treatment of choice for severe cases of foodborne illness. In 1997, 14 percent of the U.S. domestic chickens sampled were found to contain Campylobacter bacteria resistant to fluoroquinolone antibiotics. In 2000, the American Public Health Association issued an interim policy calling on manufacturers to withdraw their fluoroquinolone products used in poultry, saying that it "constitutes the quickest, most responsible way to address the public health threat."
The useful life of antibiotics for treating human disease should be extended as long as possible through careful use. This is especially critical because very few new antibiotics are being developed, and the development process often takes many years. Unnecessary antibiotic use must be curtailed in the meantime, wherever it occurs. In June 2001 the American Medical Association went on record opposing the use of antibiotics in healthy food animals. Other groups of health professionals have taken a similar stand.