A new federal analysis shows that antibiotic-resistant infections in the U.S. are climbing at a troubling pace. Between 2019 and 2023, cases of carbapenem-resistant infections — often referred to as “nightmare bacteria” — rose by nearly 70%, according to the U.S. Centers for Disease Control and Prevention (CDC).
These infections are particularly dangerous because they resist nearly every available treatment, including carbapenems, the last-resort antibiotics. Doctors are left with only two costly intravenous drugs as options for patients.
Role of the NDM Gene
The surge has been driven largely by bacteria carrying the NDM gene (New Delhi metallo-beta-lactamase), which confers powerful resistance. The CDC reported that infections tied to NDM rose from 0.25 per 100,000 people in 2019 to 1.35 in 2023 — a staggering 460% increase.
In 2023 alone, researchers identified 4,341 carbapenem-resistant infections across 29 states, including 1,831 cases linked to NDM.
Why Resistance Is Growing
Experts point to several factors behind the rise:
- Misuse of antibiotics, including taking them when unnecessary or not completing prescribed courses.
- Increased antibiotic use during the COVID-19 pandemic, which likely accelerated resistance trends.
“This is very worrisome,” said David Weiss, an infectious disease researcher at Emory University, who was not involved in the study.
Public Health Risks
The spread of resistant bacteria poses major challenges for routine health care. According to CDC epidemiologist Dr. Maroya Walters, even common illnesses such as urinary tract infections could become far more difficult to treat.
Dr. Jason Burnham of Washington University emphasized that the pandemic-driven surge in antibiotic use “likely is reflected in increasing drug resistance.”
True Numbers May Be Higher
The CDC acknowledged that its analysis likely undercounts the real scope of the problem. Many hospitals lack the tools to test for resistant strains, and the dataset excluded several of the most populous states, including California, Florida, New York, and Texas.