CDC data show 69% rise in nightmare bacteria in the US; NDM gene infections surge

Nightmare bacteria that resist multiple antibiotics rose about 69% in the United States from 2019 to 2023, according to a Centers for Disease Control and Prevention study published in the Annals of Internal Medicine. The rise was driven largely by infections caused by bacteria that carry the NDM gene, which makes them harder to treat. In 2023, researchers counted 4,341 carbapenem-resistant infections across 29 states that perform the necessary testing and reporting, of which 1,831 were the NDM variety.

Two antibiotics remain effective against NDM infections, but they are expensive and must be given intravenously, researchers said. The drugs are not widely available in all settings, and treating NDM infections can require lengthy hospital care and monitoring.

David Weiss, an infectious diseases researcher at Emory University, said the rise represents a grave danger and is worrisome. He noted that many people may be unrecognized carriers of the drug-resistant bacteria, which could fuel community spread, according to the report.

Maroya Walters, one of the study's authors, said infections once considered routine and easy to treat—such as urinary tract infections—could become chronic problems if resistant strains spread. Researchers cautioned that antimicrobial resistance occurs when germs gain the power to outsmart antibiotics, a consequence of factors including past misuse of prescriptions.

Dr. Jason Burnham, a Washington University researcher not involved in the study, suggested the COVID-19 pandemic may have contributed to the rise by expanding antibiotic use. He said the CDC's count is likely a partial picture because many states do not test or report all cases, and even in those that do, testing for certain genetic forms of resistance is not universal.

The CDC acknowledged that several large states were not included in the data, and that the national total is probably higher. The absence of information from California, Florida, New York and Texas means the reported figures underestimate the true burden, especially among hospital patients who warrant specialized testing.

This is not the first study to document a rise in NDM infections. A separate CDC report published in June noted an uptick in NDM cases in New York City between 2019 and 2024, underscoring that the trend may extend beyond the states in the current study.

Antimicrobial resistance remains a global public health threat, driven in part by the ability of bacteria to share resistance genes and spread across borders. Health officials have repeatedly warned that the misuse and overuse of antibiotics accelerate the emergence of nightmare bacteria, reminding clinicians and patients that common infections could become harder to treat if resistant strains take hold in communities.