Antibiotics have saved more human lives than almost any other scientific discovery ever made. They have been one of the most powerful weapons against the disease the world has ever known.

Unfortunately, antibiotic-resistant diseases are on the rise, thanks largely to widespread misuse of antibiotics, which speeds the evolution of antibiotic-resistant bacteria.

One of the most common types of antibiotic misuse is feeding antibiotics to healthy livestock in order to make them gain weight faster and keep them healthy in the stressful, overcrowded conditions prevalent in many factory farms and other CAFOs.

An estimated 70% of all antibiotics used in the United States are fed to healthy livestock. Some organizations place the figure even higher, as much as 78%.

Widespread use of antibiotics in livestock feed has already been fingered as a major contributing factor to the rise of MRSA, a form of antibiotic-resistant flesh eating bacteria that was once nearly unknown outside hospitals and nursing homes. Today, MRSA is growing increasingly common in otherwise healthy individuals - and it is especially prevalent among workers on large-scale hog farms, with the rate of MRSA colonization estimated to be about 25-35%, compared to 1-2% in the general population.

The hogs themselves are also susceptible to MRSA. One study in Louisiana found MRSA bacteria in about 5% of grocery store pork samples tested.

Use of routine, low dose antibiotics on hog farms is of particular concern because 95% of the 10 million pounds of antibiotics fed to hogs every year are human-use drugs.

Though there have been periodic attempts to outlaw the use of non-therapeutic antibiotics on livestock farms, they have always been blocked by the powerful agribusiness lobby.

On March 17, 2009, New York Congresswoman Louise M. Slaughter introduced the Preservation of Antibiotics for Human Treatment Act, the latest attempt to outlaw non-therapeutic use of antibiotics on livestock farms. Edward Kennedy introduced a similar bill in the Senate.

There is expected to be strong opposition from the agribusiness and pharmaceutical lobbies. In fact, the National Pork Producers Council is already calling the bill "irresponsible."

However, with the greatest life-saving drugs the world has ever known growing less effective by the day, I feel that the cost of inaction would be far greater.