Antibiotics in Environment Fuel Drug Resistance?
Antibiotics in Water and Soil May Contribute to Rising Rates of Antibiotic Resistance
May 8, 2012 -- Antibiotics found in river sediment, farmed soil, and other sources are polluting the environment and contributing to the rising rates of antibiotic resistance, a new report suggests.
Antibiotic resistance occurs when a bacteria grows immune to the effect of an antibiotic or class of antibiotics. It has been called one of the world's greatest health threats by the CDC, the FDA, and the World Health Organization.
New research in Environmental Health Perspectives analyzed how antibiotics in the environment affect illness-causing bacteria including E. coli. The researchers found that antibiotic pollution in the environment has led to the proliferation of resistant bacteria.
"This ... reinforces previous studies which highlight that antibiotic contaminants in the environment may be leading to the development of antibiotic resistance," says researcher Alfredo Tello in a news release. He is a PhD student from the University of Stirling's Institute of Aquaculture in Scotland. "Antibiotics are being overused and we're seeing the emergence of resistance to infections that we used to be able to treat."
Their overuse has caused what's called "selective pressure." When exposed to antibiotics, bacteria can either die or survive. Selective pressure occurs when these bacteria survivors replicate and their offspring quickly become the dominant type of bacteria. As a result, an army of hard-to-treat germs can arise and spread to humans.
"This adds more science to the fact that antibiotic resistance doesn't just happen at the animal level," says Gail Hansen, DVM, MPH. She is a senior officer with the Pew Charitable Trusts in Washington, D.C. "It gets get into lagoons or the environment, in general, and has an additive effect on antibiotic resistance."
She adds that "even lower levels of antibiotics can get into the environment and be high enough to cause resistance."
Sometimes, antibiotics are given to food animals to speed growth and compensate for less-than-hygienic conditions. The FDA recently gave the food industry three years to voluntarily stop using antibiotics to make food animals grow faster.
The bottom line? "Antibiotics are having an effect even after they are outside of the animal," Hansen says. "It doesn't stop."