A Pennsylvania woman developed a urinary tract infection cased by Escherichia coli bacteria that were found to be resistant to colistin, an antibiotic that is seen as the last line of defense.
Nature's Geometry/Science Source
Cattle graze in a field near Sacramento, Calif. California Gov. Jerry Brown, along with many health advocacy groups, has called the overuse of antibiotics "an urgent public health problem."
Patients receive treatment at the Chest Disease Hospital in Srinagar, India. The country has one of the highest rates of drug-resistant tuberculosis in the world, in part because antibiotics for the disease are poorly regulated by the government.
Tyson Foods says it has already reduced its use of human-use antibiotics by 80 percent over the past four years. Here, Tyson frozen chicken on display at Piazza's market in Palo Alto, Calif., in 2010.