Antibiotics have been battling bacteria and saving lives since the 1940's. Fast forward several decades, however, and the war is changing.
"Superbugs" are strains of bacteria that have become resistant to antibiotics, and they have been gaining strength and shifting the tide in their favor.
"This is really a frightening situation," Dr. Beth Bell of the CDC told CNBC's "On The Money" in a recent interview, "and really one of the most serious infectious disease threats of our time. "
CDC data show superbugs cause infections in at least two million people in the U.S. each year, and kill 23,000. Barely a week ago, in a landmark meeting, the United Nations General Assembly voted to take a coordinated approach to antibiotic resistance as a global health crisis.
By 2050, superbugs could kill 10 million people, according to the Review of Antimicrobial Resistance.
Bell, who oversees the CDC's emerging infectious disease programs, told CNBC that "in other parts of world, there are bacteria that are resistant to all known antibiotics."
If current antibiotics become ineffective, doctors will be unable to stop infections, she added.
"Antibiotic resistance and the rise of superbugs really [do] put modern medicine at risk," Bell explained.
"If you think about some of the main advances in medicine over the last number of decades, for example, cancer chemotherapy, organ transplantation, joint replacements, the success of all these innovations is really based on our ability to treat infections," she added.
The CDC says nearly one-third of all prescriptions for antibiotics are unneeded, or incorrectly prescribed by doctors, which is part of the problem. Bell told CNBC that "47 million unnecessary antibiotic prescriptions are given every year in the United States."
Antibiotic drugs that fight bacterial infections will not help viral infections like colds, flu bugs and bronchitis.
Meanwhile, most antibiotics are also used in animal agriculture to promote faster live stock growth—an overuse of antibiotics that Bell said is a "major driver" of drug resistance.
Scientists are looking for new drugs to treat evolving bacteria, but the last new class of antibiotics was discovered in the 1980's. While pharmaceutical companies led the development of new antibiotics decades ago, that has changed.
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According to the National Institutes of Health, "of the 18 largest pharmaceutical companies, 15 have abandoned the antibiotic field due to economic and regulatory obstacles."
Meanwhile the war continues, as bacteria keeps evolving.
"Superbugs are always changing and the more they change and the more antibiotics we use, the more dangerous the situation is." warns Dr. Bell.