Atlanta — The Centers for Disease Control and Prevention is warning that a stubborn class of drug resistant bacteria is spreading faster across the United States than hospitals and laboratories can track. Infections caused by New Delhi metallo beta lactamase producing carbapenem resistant Enterobacterales, known as NDM CRE, have climbed sharply, according to a new federal analysis and public health alert from the agency. The warning arrives as clinicians report more hard to treat infections across intensive care units, long term care facilities, and emergency departments, and as surveillance systems struggle to keep pace with shifting resistance patterns. CDC’s media notice spells out why the trend matters now.
The numbers are stark. Overall rates of carbapenem resistant Enterobacterales infections rose across the country between 2019 and 2023. Within that rise, the subset driven by the NDM enzyme accelerated the fastest. NDM CRE infections, once tied to care outside the United States, multiplied severalfold over that period and are now documented widely inside American health care. In New York City, for example, NDM positive cases increased from dozens to hundreds in only a few years, a local picture that mirrors the national curve. The data come into focus in a recent Annals of Internal Medicine analysis and in a separate city level bulletin published in the CDC’s journal MMWR that details the rapid shift from KPC to NDM as a dominant mechanism. That MMWR note is a reminder that mechanism level data, not just organism names, now drive both patient care and outbreak control.
Carbapenems are among medicine’s most reliable antibiotic classes for the sickest patients. The NDM enzyme breaks them. Patients with NDM CRE can develop bloodstream infections, ventilator associated pneumonia, complicated urinary tract infections, invasive wound infections, and central nervous system infections. Outcomes vary with the site of infection and the timing of effective therapy, yet mortality rises when treatment is delayed or when organisms carry multiple resistance mechanisms. For readers who need a primer, see CDC’s overview of carbapenem resistant Enterobacterales.
What changed is not the biology alone but the ecosystem surrounding it. Hospitals face chronic staffing gaps that complicate labor intensive isolation and cleaning protocols. Many clinical laboratories still do not run routine mechanism testing on every carbapenem resistant Enterobacterales isolate. That gap delays targeted therapy and slows containment. The CDC’s Antibiotic Resistance Lab Network offers mechanism testing for facilities that cannot perform it in house, but uptake and speed remain uneven. The result is a widening gap between the spread of resistance and the capacity to detect it fast enough to slow transmission. Clinicians, laboratorians, and health departments all point to the same hinge point in 2025, namely rapid carbapenemase testing that specifies whether resistance is driven by KPC, NDM, VIM, OXA 48 like, or IMP enzymes.
Clinicians still have options, but they are narrow, costly, and technically demanding. Newer agents with activity against metallo beta lactamase producers frequently require careful dosing, close monitoring, and stewardship oversight. Some regimens rely on pairing a beta lactam beta lactamase inhibitor with aztreonam for NDM producers, while others turn to siderophore cephalosporins. Treatment choices should follow formal guidance rather than improvisation at the bedside. The Infectious Diseases Society of America guidance lays out mechanism informed pathways for NDM and other carbapenemases, with practical notes on when to escalate and when to de escalate as susceptibility data return. One drug that often enters the discussion is cefiderocol. For labeling, breakpoints, and safety language, see the Food and Drug Administration’s cefiderocol information page. For a broader view of innovation and discovery, readers can also look at how artificial intelligence is reshaping the search for antimicrobials. Our earlier report on an AI discovered compound illustrates where the pipeline could go next, even if clinical use remains years away. Link that context from the phrase “newer agents” to this internal explainer: an antibiotic found with AI kills superbugs.
NDM is not new to scientists. The enzyme was first described in 2008 in Klebsiella pneumoniae isolated from a patient with recent travel to South Asia. What is new is how embedded the enzyme has become within the American microbial landscape. The gene that encodes NDM often resides on mobile DNA that passes among species in the Enterobacterales order, including E coli and Klebsiella. That mobility accelerates spread in hospitals, dialysis units, rehabilitation centers, and nursing homes where patients may share devices, rooms, or staff.
Geography used to offer a line of defense. For years, many NDM cases in the United States were tied to prior health care abroad, and hospitals were told to screen patients admitted after overseas care. That pattern is fading. Epidemiologists now see sufficient domestic transmission that international travel is no longer a reliable proxy for risk. The shift complicates triage in emergency departments and on admission to medical wards. It adds pressure to make mechanism testing routine in any Enterobacterales isolate that resists carbapenems, regardless of travel history. For global situational awareness and how other regions are adapting, see the World Health Organization’s GLASS AMR dashboard and the European Centre for Disease Prevention and Control’s 2025 risk assessment.
Even the surveillance story carries caveats. National tallies undercount because reporting and diagnostic capacity are uneven across states. Some of the largest states still do not submit complete mechanism level data, obscuring the true burden. That matters for policy and patient safety, because resources tend to follow official numbers. Where laboratory detection is patchy, outbreaks can smolder unrecognized. Hospitals that wait days for a reference lab carbapenemase result can inadvertently seed NDM CRE into downstream facilities during routine transfers. The lesson from this spring’s European variant headlines applies here too. When genomic and clinical surveillance fall behind, trend lines will surprise decision makers. Our coverage of the fast spreading Stratus variant underscored that blind spots in surveillance invite avoidable spread. The same logic applies to bacteria that do not make the evening news.
Behind the curves are patients. A middle aged man recovering after abdominal surgery spikes a fever and becomes hypotensive on day five. Blood cultures flag Enterobacterales resistant to standard drugs. The lab sends the isolate for additional testing. The team starts broad empiric therapy and contact precautions. Forty eight hours later, the carbapenemase result comes back as NDM. The regimen changes to a targeted therapy that is both expensive and logistically complex. The fever breaks after three days, yet the length of stay doubles. The unit screens roommates and recent staff contacts. In a system at capacity, each such case ripples outward through staffing, beds, and budgets.
Outpatient medicine is not insulated. Primary care and urgent care clinicians report more complicated urinary tract infections that do not respond to first line oral agents. Patients bounce between clinics and emergency departments, accumulating prescriptions while symptoms persist. Without robust local laboratory support and a culture first reflex, the mechanism that underpins the resistance can be missed, which adds selective pressure that favors the organisms clinicians are trying to suppress. The longer a resistant infection persists, the more opportunities it has to move through households and community facilities.
What actually slows NDM CRE is not one silver bullet but a playbook. It starts with fast, reliable diagnostics to identify carbapenemase production. It proceeds to standard contact precautions that are executed consistently at the bedside. That means gowns and gloves used correctly, strict hand hygiene that is measured and supported, and thorough room cleaning with agents that work on the organisms at hand. It means decontaminating shared equipment between patients and checking hard to clean reservoirs such as sink drains, splash zones, and portable imaging devices where biofilms thrive. It also means cohorting colonized patients when feasible and ensuring that staff assigned to their care do not float between high risk and lower risk units during the same shift. Practical steps are laid out in CDC’s infection control guidance for CRE and in multisociety recommendations.
The hinge is information flow. When patients move between hospitals, nursing homes, and rehabilitation centers, their resistance profiles should move with them. Too often, transfer paperwork collapses complex microbiology into a single word such as resistant. The receiving facility then has to start over. Regional coalitions that share mechanism level data allow infection preventionists to get ahead of NDM CRE rather than chase it from ward to ward. States that have built such collaboratives with seed funding after prior outbreaks have contained secondary spread faster.
Antimicrobial stewardship is the quiet lever. During early COVID surges, antibiotic prescribing spiked even though the disease is viral. That surge in unnecessary use set the stage for resistance to regain ground. Stewardship is as much about culture as rules. Clinicians need time and support to de escalate therapy when lab results return. Patients need clear explanations for why an antibiotic is not always appropriate. Health systems need pharmacists and data systems that make optimization the easiest path during a busy shift. The AR Threats program and related CDC resources summarize why that work pays off and measure progress over time. See CDC’s facts and stats on AMR.
The economics are not trivial. Mechanism testing costs money. Newer drugs are expensive. Environmental services require more time and supplies when organisms persist in wet reservoirs. But the bill for not spending is larger and harder to see. Resistant infections extend hospital stays, increase readmissions, and demand broader diagnostic workups. Families absorb the costs of missed work and prolonged caregiving. Payers cover expensive courses of intravenous antibiotics given in infusion centers or at home. A narrow focus on line item costs can obscure the systemwide expense of letting resistance run. For facilities without in house capacity, the AR Lab Network is designed to close that diagnostic gap. Details on access and supported assays are posted on CDC’s AR Lab Network profile for CRE.
Laboratories occupy the pivot between clinical care and public health. The technical capability to detect carbapenemases is widely available, yet adoption is uneven. Some hospital labs still send isolates to reference centers and wait days for results. Wider deployment of rapid phenotypic screens and molecular assays can shorten that window, but labs need funding, training, and staffing to run them consistently. National guidance helps, yet mandates without money rarely transform practice on the ground.
This story is also about the physical spaces where microbes live. The design of sinks and drains, the proximity of splash zones to patient care areas, and the plumbing in older facilities all influence how Enterobacterales move. Infection prevention teams that partner with facilities management can find and remediate reservoirs that are not obvious on a floor plan. Small architectural shifts, for example separating soiled utility rooms from medication preparation counters, produce outsized gains when organisms thrive in wet environments.
What should patients and families do when they read headlines about nightmare bacteria. The advice is practical. Ask whether a hospital tests for carbapenemases when a serious infection is suspected and whether the result will guide therapy. When a loved one is on contact precautions, take the signage seriously and resist nudging staff to cut corners. Wash hands before and after visiting and avoid handling shared medical equipment. If an infection starts in the community and does not respond to the first antibiotic, ask whether a culture was done and whether a different class of drug is indicated rather than repeating the same prescription. For a general audience summary, PBS offers a plain language explainer of the new federal findings.
For clinicians, the map of risk is changing. Travel history still matters, yet it no longer decides who needs screening on admission. Any recent stay in a hospital, rehabilitation center, or long term care facility should lower the threshold for testing when serious infection is present. When NDM CRE is identified, mechanism informed therapy should start promptly and infection prevention should be notified early. Communication at transfer is not a courtesy. It is a control measure. The IDSA guidance and CDC recommendations align on that point.
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There is reason for guarded confidence. The same public health network that learned to monitor and manage Candida auris has tools to slow NDM CRE. States that funded regional response teams, created data pipelines between facilities, and supported laboratory upgrades have documented declines after initial spikes. Hospitals that embed isolation and cleaning protocols into daily workflow, rather than treating them as emergency measures, sustain low transmission even when admitted case numbers rise.
Progress over the next year would look like this. More hospitals running routine carbapenemase testing in house. More states requiring mechanism level reporting and supporting labs accordingly. Transfer forms that include a clear section for resistance mechanisms. Pharmacy and therapeutics committees that align formularies with agents needed to treat metallo beta lactamase mediated resistance and ensure availability beyond academic centers. Public messaging that treats antimicrobial resistance as the chronic emergency it is, not a story that disappears after a news cycle. For readers interested in how foundational advances can accelerate the field, see how protein structure prediction is being used in antimicrobial design. Our report on the Nobel in chemistry and the impact of AlphaFold shows why modeling matters. Link the phrase “protein modeling advances like AlphaFold” to this internal backgrounder: AlphaFold and antibiotic research.
The CDC’s alert is a reminder that the pandemic’s collateral damage includes a backslide in everyday infection prevention. Reversing that slide requires diligent hand hygiene, exacting environmental cleaning, rapid diagnostics, and thoughtful antibiotic use. The updated multisociety hand hygiene recommendation outlines what to do and how to measure it. See the citation for the 2022 update on hand hygiene. If hospitals and laboratories rebuild those capacities with urgency, the next set of curves can bend in the other direction.
Media coverage has already amplified the signal, yet the substance sits in the data. Readers who want a narrative overview can consult the Washington Post’s report, which captures how the rise of NDM CRE affects care today.
Finally, a note on institutions and public trust. When regulators balance risk communication and practical guidance, the language can sound cautious. The Food and Drug Administration is central to that balance. For a case study in communicating uncertainty without undermining care, our recent explainer on acetaminophen during pregnancy shows how agencies and medical societies navigate public anxiety. Link the phrase “public health messaging” to this internal context piece: what FDA and others actually say.
For baseline definitions, prevention steps, and why patients should care, this CDC page remains a useful bookmark: CDC on antimicrobial resistance.
