On April 3, a Vital Signs report released by the U.S. Centers for Disease Control and Prevention said that more than 200 rare antibiotic-resistant genes were found in “nightmare” bacteria studied in 2017.

According to Dr. Anne Schuchat, principal deputy director of the CDC, about two million Americans get infections from antibiotic-resistant bacteria and about 23,000 die from the infection each year.

The CDC tested isolates of antibiotic-resistant germs from hospitals and nursing home. They found that about one in every four germs had a gene that helped to spread its resistance to antibiotics.

"This wasn't just a problem in one or two states," Schuchat said, adding that the 221 rare genes were found in isolates gathered in 27 states from infection samples that included pneumonia, bloodstream infections and urinary tract infections.

The CDC also concluded that 11 percent of people tested for the superbug carried the antibiotic-resistant gene even though they did not have any symptoms.

These bacteria evolve quickly and develop mutations that let them avoid the effects of antibiotics. If the bacteria are not stopped, the DNA can be carried via plasmids to other species of bacteria.

“Once antibiotic resistance spreads, it is harder to control—like a wildfire,” said the CDC.