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What You Need to Know About MCR-1 and Antibiotic-Resistant Superbugs


When a Pennsylvania woman was found to be carrying the MCR-1 gene—a gene that makes bacteria highly resistant to a last-resort class of antibiotics—talk of a “superbug” spread through the media. While this should serve as yet another wake-up call for all of us, there is no reason for public panic over MCR-1. Here is what you need to know.

What is MCR-1?

MCR-1 is not bacteria or a virus, but rather a gene—a piece of genetic material that allows a bacteria to become resistant to the antibiotic Colistin. Colistin is an old drug which today is used as a last resort to treat infections with bacteria that are already highly resistant to most other antibiotics.

The MCR-1 gene has spread from China to many other parts of the world, and will likely continue to do so. Similar to a handshake, it is passed from bacteria to bacteria when they are in close proximity.

The Importance of MCR-1 is Two-fold

  1. The report of this gene in a bacteria in the U.S. is a first, and has come much sooner than expected.
  2. When MCR-1 is present in bacteria called CREs (carbapenem-resistant-enterobacteriaceae), which are already highly resistant pathogens, it can make the bacteria resistant to all currently available antibiotics. That is the so-called “superbug.” For patients with serious infections, that means there may be no treatment available, taking us back to the early part of the 20th century before the discovery of antibiotics, when infection was a major cause of death in all age groups.

Why Did This Happen?

Overuse of antibiotics is certainly a major driver of the problem. One third of antibiotic use in humans has been estimated to be unnecessary. However, about 80% of the tonnage of all antibiotic use in the U.S. and around the world is in animals used for human food production. When humans are in close contact with animals on antibiotic feeds, they can acquire the resistant germs.

What You Can Do

The good news? There is no evidence so far that MCR-1 is spreading in the U.S. But there are things you can do to keep yourself as safe as possible against all germs.

  • Don’t ask for an antibiotic when your doctor says it isn’t necessary. Be relieved when you’re told you do not need an antibiotic for your cough, cold, sinus symptoms, or other viral infection.
  • Wash your hands frequently during the day.
  • Properly cook all meats, and maintain good hand washing and cleanliness, especially during food preparation.
  • Encourage your legislators to pass laws that limit or eliminate antibiotic use in the livestock industry.
author name

Joseph M. Kontra, MD

Joseph M. Kontra MD, Chief, Division of Infectious Diseases, is a physician with LG Health Physicians Infectious Diseases.

Education: Medical School–University of Pittsburgh School of Medicine; Residency–Medical College of Virginia; Fellowship–University of Pennsylvania.

Call: 717-544-3517

About LG Health Hub

The LG Health Hub features breaking medical news and straightforward advice to help individuals of all ages make healthy choices and reach their wellness goals. The blog puts articles by trusted Lancaster General Health clinical experts, good 'n healthy recipes, videos, patient stories, and health risk assessments at your fingertips.


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