Symptoms and Signs of NDM-1 Bacteria

Medical Author:
Medically Reviewed on 9/12/2022

Doctor's Notes on NDM-1 Bacteria

NDM-1 stands for New Delhi metallo-beta-lactamase, an enzyme discovered in 2009, which can be produced by some types of infectious bacteria that cause the bacteria to become resistant to many commonly used antibiotics. The beta-lactamase enzymes affect older antibiotics such as penicillins and cephalosporins and newer carbapenem antibiotics, such as imipenem, that contain a beta-lactam ring.

The main symptom of NDM-1 bacterial infection is the failure of antibiotic treatments (oral or IV) to improve a patient's condition, especially if the patient is infected with a gram-negative bacterial type and is being treated with an antibiotic that contains a beta-lactam ring structure. NDM-1 can be carried by several types of gram-negative bacteria, so symptoms of a disease are usually of little in determining whether the patient has an organism expressing the enzyme until antibiotic treatments fail. Gram-negative bacteria are known to cause many diseases (including gastrointestinal problems, urinary tract infections (UTIs), pneumonia, and some wound infections), so patients with these conditions that require antibiotics and do not recover appropriately with treatment need the gram-negative bacteria isolated and tested for antibiotic resistance.

What are the treatments for NDM-1 (New Delhi metallo-beta-lactamase)-containing bacteria?

Since most bacteria that carry the gene for NDM-1 are resistant to most or all commonly used antibiotics, treatments center on less-common antibiotics for monotherapy and/or multi-antibiotic therapy. For example:

  • Monotherapy – cefiderocol
  • Multi-antibacterial therapy – ceftazidime-avibactam plus aztreonam

The examples are recently suggested antibiotics; however, bacterial genes may rapidly change and resistance to multiple other antibiotics may emerge.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.