Antibiotic-resistant bacteria has been a growing concern in the United States, leading to thousands of deaths each year. Doctors prescribing antibiotics unnecessarily is a big contributor to the problem, and now a new analysis of government data [has] found that an estimated 30 percent of outpatient oral antibiotic prescriptions in the U.S. from 2010 to 2011 may have been unwarranted. According to the Centers for Disease Control and Prevention, antibiotic-resistant infections affect 2 million people and lead to about 23,000 deaths annually. "Antibiotic resistance is one of the most urgent public health threats of our time," Dr. Katherine E. Fleming-Dutra, of the CDC, told CBS News. "The use of antibiotics is the single most important factor leading to resistance." For the study, Fleming-Dutra and her team analyzed two CDC national surveys. The results showed that about half of the antibiotics prescribed for acute respiratory infections, including the common cold, bronchitis, and viral sore throat, may have been unnecessary. Across all conditions, about 30 percent of antibiotic prescriptions were inappropriate from 2010 to 2011. "This equates to about 47 million unnecessary antibiotic prescriptions written every year in the United States," Fleming-Dutra said. The strategy to improve outpatient antibiotic prescribing is twofold. Doctors need to be more cautious about prescribing antibiotics unnecessarily. Patients can play a role in stopping antibiotic misuse, too, [by expressing] their concerns about antibiotic overuse to their clinicians.