By Suzanne Millman, Ph.D.

Conditions in factory farms have led to the routine overuse of antibiotics, which produces antibiotic-resistant bacteria dangerous to humans and animals alike. But humane alternatives to factory farms make antibiotic use on the animals unnecessary—protecting humans from untreatable diseases and animals from crowded, unsanitary conditions.

There is little doubt that antibiotics have changed our lives for the better, making once life-threatening infections—from meningitis to pneumonia—treatable. But a disturbing trend is emerging: The number of bacteria that fail to respond to antibiotic treatment is increasing.

One cause of this increasing resistance dramatically stands out and can be corrected: the routine overuse of antibiotics on farm animals. The Union of Concerned Scientists estimates that 70 percent of the antibiotics used in the United States are fed to healthy livestock and poultry to promote growth and prevent the outbreak of disease in crowded, unsanitary factory farms. And many of the same antibiotics prescribed to humans—penicillin, tetracycline, and erythromycin—are used in these factory farms.

People can become infected with resistant bacteria while caring for farm animals who have been fed antibiotics. In turn, farm workers can pass those bacteria to others. And waterways and groundwater can become contaminated with resistant bacteria leaking from manure lagoons or manure-spread fields. These resistant bacteria can then infect people nearby who use untreated water for drinking or recreation.

Most meat sold in U.S. supermarkets now comes from factory-farmed animals, so another significant threat arises from antibiotic-resistant bacteria that infect people who eat undercooked meat or other foods contaminated with raw meat juices. But some family farmers avoid antibiotics and instead use more sustainable and humane methods, such as raising animals outdoors in small groups or in "hoop barns" that provide fresh air, space for exercise, and comfortable bedding for rest.

Because the number of antibiotic drugs is limited and few new antibiotics are available, the Food and Drug Administration and the Centers for Disease Control have cautioned that without effective action "drug choices for the treatment of common infections will become increasingly limited and expensive and, in some cases, nonexistent." As a result, antibiotics should be used prudently to prolong their effectiveness.

In 1997, the World Health Organization called for a ban on using antibiotics to promote growth in animals. In 1998, the European Union banned adding human-use antibiotics to animal feed, citing human health concerns. And the American Medical Association opposes the nontherapeutic use of antibiotics in factory-farmed animals.

The HSUS is actively involved in raising awareness about the public health issues of factory farm antibiotic use in livestock and poultry and encourages regulation of this practice.

Suzanne Millman is Director of Scientific Programs for the The Farm Animals and Sustainable Agriculture section of The HSUS.