A new study from CDC scientists shows that a dangerous strain of what some researchers have nicknamed a “superbug” is on the rise.
The study, published on September 22 in the Annals of Internal Medicine, examines a bacteria called NDM-producing carbapenem-resistant Enterobacterales (NDM-CRE). Researchers found that, between 2019 and 2023, NDM-CRE infections surged by more than 460% in the U.S. These infections, which range from pneumonia to bloodstream and urinary tract infections, are extremely hard to treat and can be deadly due to their antibiotic-resistant properties—hence the name “superbug.”
What is a “superbug”?
A “superbug” is a colloquial term for a strain of bacteria that has developed resistance to the drugs that were once able to kill it, particularly one that is spreading at a concerning rate.
According to a January article from the CDC, antimicrobial resistance develops when drugs—like antibiotics and antifungals—pressure bacteria and fungi to adapt. These germs then develop resistance mechanisms in order to survive. Alarmingly, the CDC adds, “antimicrobial-resistant germs can share their resistance mechanisms with other germs that have not been exposed to antibiotics or antifungals.”
Essentially, “nightmare bacteria” lead to infections that are very difficult for doctors to treat.
What is NDM-CRE?
NDM-CRE is a sub-group of the bacteria known as carbapenem-resistant Enterobacterales (CRE), which are resistant to some of the strongest antibiotics available. A 2022 report from the CDC, COVID-19: U.S. Impact on Antimicrobial Resistance, showed that, in 2020 alone, CRE was responsible for 12,700 infections and 1,100 deaths in the U.S.
The second part of the acronym, “NDM,” represents this strain’s particular properties. It stands for “New Delhi metallo-β-lactamase,” which, per the CDC, is “an enzyme that makes these bacteria resistant to nearly all available antibiotics, leaving few treatment options.”
Why is an NDM-CRE infection so serious?
NDM-CRE infection is dangerous for a number of reasons. To start, due to the strain’s former obscurity, many doctors may not suspect it when diagnosing CRE infections. Once it is identified, though, researchers told NBC News that there are just two antibiotics that work against the infection, though both are expensive and have to be administered by IV. Because of how difficult they are to treat, NDM-CRE infections are associated with high risks of morbidity and mortality.
Why is it spreading?
According to a September 23 article from the CDC, the exact reasons for the surge in NDM-CRE infections is unknown. However, the agency believes it may be related to “gaps in infection control” (like hand hygiene, wearing gloves, and proper disinfection in healthcare settings) and limited testing may be to blame.
“Many hospitals and clinics do not have the tools to rapidly detect NDM-CRE infections or the presence of these dangerous germs in patients who aren’t yet sick,” the article explains. “Delayed identification leads to slower treatment, increased transmission, and missed opportunities for infection control.”
What can be done?
The CDC recommends four courses of action for healthcare providers to help contain the spread. These include staying informed about the rising threat of NDM-CRE; testing carbapenemase strains as quickly as possible in infected patients; prescribing antibiotics carefully; and following infection control protocol as closely as possible. The full breakdown can be found here.