CRKP is a word that fell out of use, and that tells you something
In 2011 the acronym in every headline was CRKP, carbapenem-resistant Klebsiella pneumoniae. You will barely see it now. Laboratories and public health agencies talk about CRE instead, carbapenem-resistant Enterobacterales, a family that includes Klebsiella along with E. coli, Enterobacter, Serratia and their relatives in the gut.
The rename happened because the species turned out to be the least interesting part. Resistance here rides on plasmids, small loops of DNA that one organism hands to another. A carbapenemase gene sitting in Klebsiella one week can be in E. coli the next, inside the same patient. The useful question stopped being which bug and became which gene. CDC now sorts these isolates by carbapenemase: KPC, NDM, OXA-48-like, VIM, IMP.
The World Health Organization’s 2024 Bacterial Priority Pathogens List puts carbapenem-resistant Enterobacterales in the critical category, the top tier, next to carbapenem-resistant Acinetobacter baumannii and rifampicin-resistant tuberculosis (1). MRSA sits a rung lower, in the high category (1). That is a distinction worth keeping. The organism most people have heard of ranks below the one they have not.
What the current US numbers actually say
CDC published a five-year analysis in Annals of Internal Medicine in September 2025, drawing on 29 states that require submission of carbapenem-resistant isolates, covering about 35 percent of the US population (2). Carbapenemase-producing CRE went from 2,267 cases in 2019 to 4,341 in 2023. Age-adjusted incidence up 69 percent. The subgroup driving that rise was NDM, up 461 percent across the same five years (2).
The NDM figure is the one I pay attention to. NDM stands for New Delhi metallo-beta-lactamase, and it matters because most of the newer agents built for CRE were built against KPC, the carbapenemase that used to dominate here. In CDC’s own Emerging Infections Program laboratory data, published in Emerging Infectious Diseases in May 2026, the share of carbapenemase-producing CRE isolates carrying blaNDM climbed from 5.4 percent in 2016 to 39.8 percent in 2023 (3). By 2023, NDM was present in 27 percent of carbapenem-resistant E. coli (2).
Now the scale. Unadjusted incidence of carbapenemase-producing CRE in that 29-state cohort was 3.67 per 100,000 people in 2023 (2). Roughly four isolates per hundred thousand residents in a year.
MRSA is far more common, and its curve is flatter than the headlines suggest. Six surveillance sites counted 43,921 MRSA bloodstream infections between 2005 and 2022 (4). Incidence dropped from 32.6 per 100,000 in 2005 to 15.7 in 2016, and then the decline stopped and reversed upward through 2019, before the pandemic (4). Worldwide, deaths directly attributable to MRSA rose from 57,200 in 1990 to 130,000 in 2021 (5).
If you are reading this at home and feeling fine
Here is what the 2011 coverage never gave you. CRE is a healthcare organism. In CDC population-based surveillance across eight US sites, 1,499 CRE cases were identified and only 149 of them, 10 percent, occurred in someone with no healthcare risk factor at all (6). Overall CRE incidence in that surveillance was 2.96 per 100,000 per year. For the community-associated cases it was 0.29 (6). Of those community cases, 98 percent came from urine cultures (6).
MRSA bacteremia has the same shape. Of those 43,921 bloodstream infections, 62.3 percent were healthcare-associated community-onset, meaning the person was not an inpatient when the culture was drawn but had dialysis, recent surgery, a catheter or a recent admission behind them. Another 18.7 percent started in the hospital. That leaves 18.2 percent with no healthcare link (4), and the group driving the rise in that last category before 2020 was people who inject drugs (4).
The median age of a CRE patient in Tennessee’s 2016 to 2022 surveillance was 69.5 years (7).
So if you have not been hospitalized, have no indwelling device, are not on dialysis, do not live in a long-term care facility, have not had an overnight hospital stay or a procedure outside the United States or Canada in the past year, and have not been through repeated courses of broad-spectrum antibiotics, your CRE risk sits near that 0.29 per 100,000. I am going to say that without hedging, because hedging it does you no favors. The people who genuinely need to worry about CRE mostly already know they are seriously ill.
The one about care abroad is worth spelling out, because most people would not recognize it as a risk factor at all. Minnesota’s health department, to take one state’s version of a rule many run, tells hospitals to ask every patient on admission whether in the previous twelve months they have had an overnight stay in a healthcare facility outside the United States or Canada, or surgery or dialysis there. Anyone who has is tested for a carbapenemase-producing organism and kept in contact precautions until the result comes back negative (10). It is not a rule about travel in general. It is about having been a patient somewhere else.
The boil you had is a different problem
You may have had a hot red lump that got drained and cultured out as MRSA. That is community-associated MRSA skin infection, and it is a separate clinical animal from the resistant gram-negatives that make the news.
The May 2026 American Family Physician review on skin and soft tissue infections lands where practice has sat for years. Drainage is the treatment. Antibiotics after drainage lower the chance of failure and recurrence, and do not substitute for the procedure (8). Trimethoprim-sulfamethoxazole or clindamycin covers community MRSA (8). One detail worth having if anyone offers you a nasal swab: a negative nasal MRSA PCR does not rule out MRSA as the cause of a cellulitis or an abscess (8).
I send a suspected abscess out for same-day drainage rather than treating it empirically and waiting. Drainage is what cures an abscess, and an antibiotic on its own is neither necessary nor sufficient.
There is a second reason I do not send the prescription, and it has more to do with what people actually do than with what the guideline says. If I hand someone an antibiotic, most of them will not then go and get the incision and drainage done. They will take the pills and wait to see what happens. That is a completely human response and I understand it. It also means the prescription has quietly replaced the treatment while the abscess is still sitting there. So I say the same thing every time, which is that this needs to be looked at in person today, at an urgent care or an emergency department.
Having had a MRSA boil does not put you on a path toward CRE. Different organism, different reservoir.
For clinicians, the report line is no longer the answer
Where resistance actually surfaces in ordinary outpatient work is recurrent urinary infection, and that is the one I have a firm threshold on. If someone was treated for a UTI within the last 30 days and is back with the same symptoms, or if they are 60 or older, they go for in-person testing and a urine culture rather than another empiric course from me. A second guess at the antibiotic is how a resistant organism gets a further week to work with. The culture is the only thing that tells you what you are treating, and a video visit cannot produce one.
I also do not treat male urinary symptoms remotely at all. Bladder infection is uncommon enough in men that when it does occur the organism is more often a resistant one, and the differential runs through prostatitis and sexually transmitted infection, neither of which a course of nitrofurantoin is going to fix.
Two things should change what you do.
The word CRE on a micro report has stopped being sufficient. Treatment now depends on carbapenemase class, and the CDC authors say so plainly: carbapenemase testing is limited in clinical laboratories, public health laboratory results often arrive too late for the decision in front of you, and susceptibility testing for aztreonam-avibactam and cefiderocol, the only beta-lactam-based agents active against NDM, is not widely available (2). A ceftazidime-avibactam reflex that was defensible in a KPC-dominant era will fail against an NDM producer. Learn your local carbapenemase mix.
Admission risk prediction also works better than most of us assume. A model validated in 2025 against Atlanta public health data and then replicated inside an academic health system identified patients at high risk of carrying CRE on admission using age, prior infection diagnosis, and the number and mean length of acute care hospitalizations in the preceding year, reaching an area under the curve of 0.85 in the public health dataset; adding Elixhauser comorbidity score, antibiotic days of therapy in the prior year, diabetes and prior ICU admission improved performance within the health system (9). Antibiotic days in the prior year is the variable you can actually move.
The outcomes justify the attention. In Tennessee surveillance, carbapenemase-producing CRE carried more than double the odds of death at 90 days compared with non-carbapenemase-producing CRE (odds ratio 2.22, 95 percent CI 1.12 to 4.42) (7).
I do not routinely ask about hospitalization outside the United States when someone reports recurrent urinary tract infections. That is a description of my practice, not a defense of it. The NDM figures above, and the travel and foreign-healthcare exposure that sits behind much of that risk, are printed a few paragraphs from that sentence, and a reader who notices the gap between the two is reading correctly.
The Bottom Line
CRKP became CRE because the resistance gene travels between species and now matters more than the name of the organism carrying it. Carbapenemase-producing CRE is rising here, 69 percent higher in age-adjusted incidence from 2019 to 2023, with NDM up 461 percent (2). At 3.67 cases per 100,000 it stays uncommon, and it stays concentrated. Ninety percent of CRE cases in CDC surveillance had a healthcare risk factor (6). About 81 percent of MRSA bloodstream infections were hospital-onset or healthcare-associated (4).
If you are healthy, out of the hospital and free of devices, these organisms are a public health problem you should want funded, not a personal threat that should cost you sleep. If you are on dialysis, living in long-term care, carrying a central line, or coming off months of broad-spectrum antibiotics, the math is different. The conversation to have with your physician then is about lines and antibiotic exposure, not about hand sanitizer.
Related Reading
Why Won’t Antibiotics Cure a Viral Infection? Doctor Explains Antibiotic Resistance Could End Modern Medicine, WHO Warns I hear it almost every day now. “I think I just need a Z-Pak.” Abscesses – What to do about MRSA (Methicillin-resistant Staphylococcus aureus)Scott Rennie, D.O.
Board Certified in Obesity Medicine and Family Medicine
This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.
Sources
1. World Health Organization. WHO updates list of drug-resistant bacteria most threatening to human health. 17 May 2024. https://www.who.int/news/item/17-05-2024-who-updates-list-of-drug-resistant-bacteria-most-threatening-to-human-health and WHO bacterial priority pathogens list, 2024. https://www.who.int/publications/i/item/9789240093461
2. Rankin DA, Stahl A, Sabour S, Khan MA, Armstrong T, Huang JY, Baggs J, Spalding Walters M. Changes in Carbapenemase-Producing Carbapenem-Resistant Enterobacterales, 2019-2023. Ann Intern Med. 2025 Sep 23;178(12):1818-1821. https://pmc.ncbi.nlm.nih.gov/articles/PMC12645407/
3. Increase in blaNDM among Carbapenemase-Producing, Carbapenem-Resistant Enterobacterales, United States, 2016-2023. Emerg Infect Dis. 2026 Jun;32(6). Published online 27 May 2026. https://wwwnc.cdc.gov/eid/article/32/6/25-1404_article
4. Biggs HM, Li R, Jackson KA, Nadle J, Petit S, Ray SM, Lynfield R, Como-Sabetti K, Dumyati G, Gellert A, Walsh M, Schaffner W, Baggs J, See I. Trends in Incidence and Epidemiology of Methicillin-Resistant Staphylococcus aureus Bacteremia, Six Emerging Infections Program Surveillance Sites, 2005-2022. Open Forum Infect Dis. 2025;12(6):ofaf282. https://pmc.ncbi.nlm.nih.gov/articles/PMC12125674/
5. GBD 2021 Antimicrobial Resistance Collaborators. Global burden of bacterial antimicrobial resistance 1990-2021: a systematic analysis with forecasts to 2050. Lancet. 2024;404(10459):1199-1226. https://pubmed.ncbi.nlm.nih.gov/39299261/
6. Bulens SN, Reses HE, Ansari UA, et al. Carbapenem-resistant Enterobacterales in individuals with and without health care risk factors, Emerging Infections Program, United States, 2012-2015. Am J Infect Control. 2023 Jan;51(1):70-77. https://pmc.ncbi.nlm.nih.gov/articles/PMC10881240/
7. Muleta D, Nouer SS, Tolley EA, Villegas RM, Taylor J, Harriott MM. Epidemiology of carbapenem-resistant Enterobacterales infections in Tennessee, 2016-2022. Epidemiol Infect. 2025 Sep 8;153:e119. https://pmc.ncbi.nlm.nih.gov/articles/PMC12529416/
8. Chambliss ML, Rumball A, Brown CM. Skin and Soft Tissue Infections. Am Fam Physician. May 2026. https://www.aafp.org/afp/2026/0500/skin-soft-tissue-infections
9. Prakash-Asrani R, Bower C, Robichaux C, Chan B, Jacob JT, Fridkin SK, Howard-Anderson J. Identifying patients at high risk for carbapenem-resistant Enterobacterales (CRE) carriage on admission to acute care hospitals: validating and expanding on a public health model. Infect Control Hosp Epidemiol. 2025 Apr;46(4):398-403. https://pmc.ncbi.nlm.nih.gov/articles/PMC12015620/
10. Minnesota Department of Health. Health Advisory: Hospital Admission Screening for CPO and C. auris. 26 August 2021. https://www.health.mn.gov/communities/ep/han/2021/aug26cpo.pdf