A bacterial strain that disables the strongest class of antibiotics available in American hospitals is spreading faster than infection-control programs can contain it. NDM-producing carbapenem-resistant Enterobacterales, a family of gut bacteria armed with the New Delhi metallo-beta-lactamase enzyme, have surged across U.S. healthcare facilities since 2019. In New York City alone, confirmed NDM-positive CRE cases climbed from 58 in 2019 to 388 in 2024, a more than sixfold increase that reflects a broader national pattern tracked by the CDC through multiple surveillance systems.
Why NDM-CRE is outrunning hospital defenses
Carbapenem antibiotics are often the last effective option for patients with severe drug-resistant infections. NDM-CRE defeats those drugs and also resists treatments that still work against the more familiar KPC form of carbapenem resistance. The CDC has noted that NDM confers resistance to agents often used for KPC-CRE, including ceftazidime-avibactam, a combination antibiotic that many hospitals rely on as a frontline rescue therapy. That distinction matters because clinicians who treat an NDM infection with a KPC-targeted regimen risk therapeutic failure in patients who are already critically ill.
The practical result is that hospitals cannot apply a single playbook for all carbapenem-resistant infections. Each case now requires rapid identification of the specific resistance mechanism before doctors can choose an antibiotic with any chance of working. That extra diagnostic step takes time, and many community hospitals lack the molecular testing capacity to perform it on site. Samples may need to be shipped to reference laboratories, delaying results for days while patients remain on empiric therapies that may be ineffective against NDM-CRE.
A central question is whether the acceleration after 2022 reflects repeated introductions of NDM-carrying bacteria from countries where the enzyme is endemic, or whether the strains are now spreading from patient to patient within interconnected U.S. hospital networks. If domestic transmission is the primary driver, the threat is harder to manage through travel screening alone. Infection-control strategies would need to shift toward aggressive inter-facility communication, shared patient alerts, and routine carbapenemase testing at admission, particularly for patients transferring between long-term care facilities and acute-care hospitals.
NDM-CRE also presents practical challenges for day-to-day infection prevention. Patients colonized with the organism may show no symptoms but can still seed outbreaks when moved between wards or facilities. Cohorting colonized patients, enforcing contact precautions, and dedicating staff or equipment are all resource-intensive steps that many understaffed hospitals struggle to sustain. As NDM-CRE becomes more common, those extraordinary measures risk becoming routine, stretching infection-control teams that are already managing other multidrug-resistant organisms.
CDC surveillance data documents a sharp national rise
Two independent CDC surveillance platforms confirm the trend. The Antimicrobial Resistance Laboratory Network analyzed national data on carbapenemase-producing CRE from 2019 to 2023 and found sharp growth driven by NDM. That analysis showed NDM-positive isolates increasing both in absolute numbers and as a share of all carbapenemase-producing Enterobacterales, signaling that the enzyme is no longer a rare import but a growing part of the domestic resistance landscape.
Separately, the CDC’s Emerging Infections Program used its MuGSI platform to quantify the distribution of carbapenemase genes across confirmed cases from 2016 through 2023, showing that the proportion carrying the blaNDM gene rose substantially relative to the previously dominant blaKPC gene. While KPC remains common, the expanding footprint of NDM means clinicians can no longer assume that a carbapenem-resistant infection will respond to KPC-focused therapies. For stewardship teams, that shift complicates empiric treatment guidelines and forces more nuanced decision-making under time pressure.
New York City’s experience offers the most granular local picture. The city’s health department documented NDM-positive CRE cases rising from 58 in 2019 to 388 in 2024, according to a CDC field report. That trajectory did not plateau; each year brought a higher count than the last, suggesting sustained transmission rather than a single outbreak. The city’s data also showed that NDM-CRE required what the CDC called “mechanism-specific therapy,” meaning that standard CRE treatment protocols were not sufficient and that prescribers had to consider newer or less familiar agents.
At the state level, jurisdictions such as Washington have classified CRE as a notifiable condition, requiring laboratories and clinicians to report confirmed cases to public health authorities. The CDC has described the rise as a sharp increase in dangerous bacteria, framing NDM-CRE as a distinct clinical challenge that demands targeted responses rather than generic antimicrobial stewardship. That framing underscores that simply reducing overall antibiotic use, while important, will not by itself reverse the spread of this particular resistance mechanism.
Gaps in geographic tracking and patient outcomes
The available surveillance data establishes that NDM-CRE is growing, but several questions remain unanswered. Neither the AR Lab Network summaries nor the Emerging Infections Program analyses published through 2023 include facility-specific breakdowns that would reveal whether a small number of hospital clusters account for most of the increase, or whether the spread is diffuse across regions. Without that granularity, public health officials cannot easily target interventions at the highest-risk transfer corridors or understand how much of the burden falls on long-term acute-care hospitals and nursing facilities.
Patient-level outcome data is also absent from the primary surveillance reports. The CDC tracks case counts and resistance mechanisms, but published summaries do not yet link NDM-CRE infections to mortality rates, lengths of stay, or treatment success with newer agents such as cefiderocol or combination beta-lactam/beta-lactamase inhibitors that retain activity against metallo-beta-lactamases when paired with additional drugs. That gap makes it difficult to quantify the human cost beyond the count of confirmed infections or to compare NDM-CRE outcomes with those of other resistant organisms.
National incidence data beyond 2023 has not yet appeared in the primary surveillance summaries, creating a lag between what hospitals are experiencing and what the published record shows. New York City’s 2024 figure of 388 cases is the most recent data point available, and it comes from a single jurisdiction with robust laboratory capacity. Whether other major metropolitan areas are seeing comparable acceleration is not yet documented in the public record, leaving clinicians elsewhere to rely on anecdotal experience and local laboratory alerts rather than comprehensive benchmarks.
The absence of detailed epidemiologic mapping also complicates planning at the federal level. Agencies such as the Department of Health and Human Services, which coordinates national health security efforts through federal health programs, depend on timely, geographically resolved data to prioritize funding for laboratory capacity, infection-prevention training, and stockpiles of last-line antibiotics. Without clearer visibility into where NDM-CRE is most entrenched, investments risk arriving late or missing the facilities that need support most urgently.
What patients and hospitals can do now
For patients and families, the practical takeaway is direct. Anyone facing a serious hospital-acquired infection, especially after surgery, intensive care, or a prolonged stay in a nursing facility, should feel comfortable asking whether the infecting organism has been tested for carbapenem resistance and, if so, which resistance mechanism is involved. Understanding whether an infection is caused by NDM-CRE rather than another form of CRE can shape both treatment options and expectations about recovery.
Basic infection-prevention steps remain critical. Hand hygiene before and after touching a patient, consistent use of gowns and gloves when recommended, and careful management of devices such as urinary catheters and central lines can all reduce the risk of acquiring or transmitting NDM-CRE. Families can support these efforts by reminding visitors to clean their hands and by speaking up if they notice lapses in precautions around a high-risk patient.
Hospitals, meanwhile, can use the emerging data as a signal to strengthen surveillance and communication. Routine carbapenemase testing for high-risk patients at admission, rapid notification when an NDM-CRE carrier is transferred, and close collaboration with public health departments can slow spread even in the absence of perfect national maps or detailed outcome statistics. As NDM-CRE continues to expand its footprint, those local actions may determine whether the organism remains a manageable threat or becomes a fixture of American healthcare.
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*This article was researched with the help of AI, with human editors creating the final content.
