Each year, approximately two million Americans become sick because of their resistance to antibiotics. Not only are humans becoming resistant to these drugs, but now birds and other wildlife have become susceptible.


Scientists recently tested crow feces at Coes Pond in Worcester, Mass., and discovered that the crow’s genes are now  resistant to antibiotics. Crow feces were also studied in three other states confirming that antibiotic resistance has spread to wildlife, worrying some experts.

Drug resistant infections are steadily on the rise, mainly due to overuse of antibiotic drugs in medicine and livestock. Experts, including Julie Ellis, a researcher at Tuft’s University, now worries about the spread to wildlife.

Ellis said, “We’ve documented human-derived drug resistance where it shouldn’t be – in wildlife and the environment. But we know very little about how this may impact public health. There just isn’t that smoking gun.”

The resistance genes were also discovered in other animals including houseflies, moths, gulls, foxes, sharks and whales.


These bacterias are able to swap genes and pass it on to the next generation to halt an antibiotic assault, spreading the resistance between microbes around the world. According to Lance Price of George Washington University the bacteria that “pick up resistance genes survive better in an environment where antibiotics are being used. They can outcompete all the other bacteria.”

During the research conducted on the crows, scientists were able to gather 600 fecal samples in four states: Massachusetts, Kansas, New York and California. In about 2.5 percent of the samples, genes that were resistant to vancomycin, a drug used in hospitals as a last resort, were found. Since the vancomycin resistant gene is so rare, researchers were surprised to find genes that were resistant to the drug in wildlife.

Tracing the resistance back to the source can be very difficult and sometimes the source cannot be determined. Researchers suspect that waste sites may have played a role in being the source of the crow’s bacteria. In the past, research on drug resistance has been mostly focused on hospitals, but now has shifted attention to the environment as the source of drug resistance. Currently, about 30,000 tons of antibiotics are sold and used each year for livestock and food-producing animals, leading many people who consume these foods, to become antibiotic-resistant.

Image Source: Joi Ito/Flickr