Rising Threat of NDM-CRE: CDC Epidemiologist Highlights Urgent Infection Prevention Priorities

Carbapenem-resistant Enterobacterales (CRE) carrying New Delhi metallo-β-lactamase (NDM) are on the rise across the US, posing a growing challenge for hospitals, infection preventionists, and public health officials. In a recent interview, Danielle Rankin, PhD, MPH, CIC, an epidemiologist with the CDC, discussed her recently published study, which underscored the scale of the problem and the need for coordinated action.

“NDM is a type of carbapenemase, which is an enzyme that can inactivate carbapenems and other beta-lactam antibiotics,” Rankin explained. “Carbapenemase, like NDM, can share [its] genetic code with other bacteria, even if they were previously susceptible, rapidly spreading resistance.” Transmission most often occurs in health care settings, through direct contact, contaminated medical equipment, or environmental reservoirs such as sink drains and toilets.

CDC surveillance data revealed a dramatic rise in NDM-CRE. “Through the Antimicrobial Resistance Laboratory Network data, we recognized that NDM was actually increasing,” Rankin said. The CDC created a cohort of 29 states to analyze CRE isolates and track carbapenemase trends systematically. Results show NDM-CRE incidence has surged by more than 460%.

For clinicians, these shifts complicate empiric therapy. “There’s really not a one-size-fits-all approach,” Rankin noted. Facilities must foster close collaboration among microbiology labs, pharmacists, infectious disease specialists, and public health departments to adapt local guidelines.

Testing capacity also remains a bottleneck. Carbapenemase mechanism testing is often unavailable at the local level, leading to delays. “Clinical laboratories that perform inhouse testing have a marked advantage, with turnaround times around 6 days faster than public health labs,” she said. “By enhancing local testing capabilities, we can improve the timeliness of results and facilitate more effective and targeted patient care in the face of multidrug-resistant organisms.”

Infection preventionists must prepare for what Rankin described as a “poly-carbapenemase landscape,” where multiple resistance mechanisms, including OXA-48, may coexist. Vigilance is essential: “It’s important to remain suspicious if you’re seeing a rise in a single mechanism, even across different organisms.”

Environmental hygiene is another critical front. Rankin warned that sink biofilms can serve as hidden reservoirs: “If a faucet is directly over a sink drain, it can splash into that drain and then onto items around the sink,” enabling horizontal transmission to patients.

As NDM-CRE becomes more common, outbreak detection strategies must evolve beyond case-by-case responses. Whole genome sequencing and targeted screening of high-risk patients are among the tools CDC is piloting. “To prevent outbreaks,” Rankin emphasized, “facilities should continue monitoring hand hygiene, [personal protective equipment] use, and environmental cleaning and disinfection as well as sink hygiene.”

Read Rankin and her colleagues’ study published in the Annals of Internal Medicine here.

Enterobacterales bacterium

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