A new superbug is on the rise in the United States, and it’s a big one. Dubbed the “phantom menace” by scientists, the carbapenem-resistant Enterobacteriacae (CRE) has the potential to become widespread thoughout the country.

The CRE family is known to be resistant to most antibiotics, and therefore very difficult to treat. The bacteria can also be quite deadly — up to 50 percent of infected patients die, according to the Centers for Disease Control and Prevention (CDC). Health officials say CRE is one of the country’s most urgent health threats.

The specific bacteria that earned a report from the CDC on Thursday is a relatively new brand of the bacteria. Unlike the other, more common types of CRE, the superbug carries a plasmid — a mobile piece of DNA capable of breaking down antibiotics with an enzyme. It gets worse; the bacteria also has the ability to transfer that plasmid and its antibiotic resistance to normal bacteria present within our bodies.

Currently, this type of CRE is rare and hasn’t been a focus of testing due to the fact that it is actually less antibiotic-resistant than other, more common types of CRE. For this reason, health officials gave it its ominous nickname.

“This is a tricky drug-resistant bacteria, and it isn’t easily found,” CDC Director Thomas Frieden told The Washington Post. “What we’re seeing is an assault by the microbes on the last bastion of antibiotics.”

One example of the problems CRE bacteria are capable of causing is a recent incident in China, where plasmids gave the bug’s resistance to an antibiotic called colistin. Many health professionals consider colistin one of the last lines of defense against certain dangerous bacteria such as this.

These bacteria “are of greatest public health concern because of their potential for rapid global dissemination," the report said.

It is important to note, however, that these infections are not something the general populace needs to worry about quite yet. Dr. William Schaffner, an infectious disease specialist and professor of preventative medicine at Vanderbilt University Medical Center in Nashville told Live Science that microbiologists, public health officials, and infectious disease experts are paying close attention for everyone.

Schaffner explained that even if bacteria are only resistant to certain types of antibiotics, its concerning to experts because this reduces the number of treatments doctors can use to take out the infections. Doctors need several types of antibiotics available, he said, and the more options there are, the better.

Source: Lyman M, Walters M, Lonsway D, Rasheed K, Limbago B, Kallen A. Notes From The Field: Carbapenem-resistant Enterobacteriaceae Producing OXA-48-like Carbapenemases—United States, 2010-2015. Morbidity and Mortality Weekly Report, Centers for Disease Control. 2015.