Superbugs: What They Are and How You Get Them

Medically Reviewed by Hansa D. Bhargava, MD on April 17, 2015

April 17, 2015 -- Imagine being sick in the hospital with a bacterial infection and doctors can't stop it from spreading. This so-called "superbug" scenario is not science fiction. It's an urgent, worldwide worry that is prompting swift action.

Every year, about 2 million people get sick from a superbug, according to the CDC. About 23,000 die. Earlier this year, an outbreak of CRE (carbapenem-resistant enterobacteriaceae) linked to contaminated medical tools sickened 11 people at two Los-Angeles area hospitals. Two people died, and more than 200 others may have been exposed.

The White House recently released a comprehensive plan outlining steps to combat drug-resistant bacteria. The plan identifies three "urgent" and several "serious" threats. We asked infectious disease experts to explain what some of them are and when to worry.

But First: What's a Superbug?

It's a term coined by the media to describe bacteria that cannot be killed using multiple antibiotics. "It resonates because it's scary," says Stephen Calderwood, MD, president of the Infectious Diseases Society of America. "But in fairness, there is no real definition."

Instead, doctors often use phrases like "multidrug-resistant bacteria." That's because a superbug isn't necessarily resistant to all antibiotics. It refers to bacteria that can't be treated using two or more, says Brian K. Coombes, PhD, of McMaster University in Ontario.

Any species of bacteria can turn into a superbug.

Misusing antibiotics (such as taking them when you don't need them or not finishing all of your medicine) is the "single leading factor" contributing to this problem, the CDC says. The concern is that eventually doctors will run out of antibiotics to treat them.

"What the public should know is that the more antibiotics you’ve taken, the higher your superbug risk," says Eric Biondi, MD, who runs a program to decrease unnecessary antibiotic use. "The more encounters you have with the hospital setting, the higher your superbug risk."

"Superbugs should be a concern to everyone," Coombes says. "Antibiotics are the foundation on which all modern medicine rests. Cancer chemotherapy, organ transplants, surgeries, and childbirth all rely on antibiotics to prevent infections. If you can't treat those, then we lose the medical advances we have made in the last 50 years."

Here are some of the growing superbug threats identified in the 2015 White House report.

Urgent Threat: Carbapenem-Resistant Enterobacteriaceae (CRE)

What is it?It's afamily of bacteria normally found in your gut. But many types of CRE are resistant to all antibiotics, including carbapenem, which is usually the last resort. E. coli is an example.

How do you get it? Healthy people usually don't get this type of infection. Most cases are in people who are in the hospital or a medical care facility, like a nursing home. The bacteria can be hard to remove from medical tools that are placed into the body, such as catheters, breathing tubes, or viewing scopes, even after cleaning. That’s what happened in California, after doctors unknowingly used contaminated endoscopes on patients.

Why is it a concern?They can cause life-threatening blood infections. "There are no effective treatments," Coombes says. Some research says that up to 50% of patients who are sick from CRE die because of it, according to the CDC.

Urgent Threat: Neisseria gonorrhoeae

What is it? This strain of bacteria causes gonorrhea, a sexually transmitted disease (STD).

How do you get it? Anyone who has sex can get this infection. It commonly spreads during oral, anal, or vaginal contact. If you are pregnant, you can pass this infection to your baby during childbirth.

Why is it a concern? Every year, hundreds of thousands of people get gonorrhea. Some people do not have symptoms. That means you can spread it without knowing. It used to be treatable with antibiotics. But the bacteria are becoming more resistant to current drugs, says Eric Biondi, MD, of the University of Rochester in New York. Untreated, gonorrhea can lead to infertility in men and women. It also increases your risk for HIV and other STDs. Rarely, it can cause life-threatening blood infections.

Urgent Threat: Clostridium difficile (C. diff)

What is it? It's a type of bacteria that can live in your intestines. Usually, it does no harm. But some things can cause it to overgrow, triggering serious problems.

How do you get it? Most people who get a C. diff infection are getting medical care. The biggest risk factor is taking antibiotics. While antibiotics may cure the bacteria that are making you sick, the drugs can also knock out the healthy bacteria in your digestive tract. Then C. diff takes over.

Why is it a concern? A C. diff infection can cause life-threatening diarrhea. About 14,000 people a year die from it, most of them older adults. In severe cases, you may need surgery to remove part of the infected intestine.

Particles of the bacteria, called spores, can be left behind in bathrooms, on linens, or on clothing. They can be passed from person to person. In the past, doctors used antibiotics called fluoroquinolones to treat C. diff. But these drugs don't always work. From 2000-2007, deaths spiked 400% when a new drug-resistant strain of C. diff appeared.

Serious Threat: Multidrug-Resistant Acinetobacter

What is it? It is a bacteria found in soil and water, which can also live on your skin for days. It doesn't always make you sick. A superbug strain that doctors worry about is Acinetobacter baumannii.

How do you get it? People outside the hospital usually don't get sick from this germ. It's most often seen in people who are already ill and in the hospital for another reason. Having a breathing tube raises your risk.

Why is it a concern? Doctors call this a "significant" hospital germ. It "can develop antibiotic resistance more rapidly than many other bacteria," Coombes says. It "can cause serious illness and can infect the sickest patients." These bacteria cause dangerous lung, brain, and urinary tract infections, among others. About 12,000 people get this infection in hospitals every year. Most are resistant to multiple antibiotics.

This superbug is considered a "survivor" because it forms a protective shield against antibiotics. It is tough to treat because it can easily spread between people.

Serious Threat: MRSA

What is it?MRSA stands for methicillin-resistant Staphylococcus aureus. It is a type of bacteria that cannot be treated with penicillin.Many healthy people have staph on their skin and in their nose and it doesn't make them sick. But you can spread it to others.

How do you get it? This infection most often happens to people in the hospital, often after surgery. It can infect a wound and spread to surrounding tissues and your blood. But new strains have emerged outside medical settings. There have been recent concerns about MRSA outbreaks among athletes, including in schools. The bacteria can spread easily with skin-to-skin contact. Your risk is higher if you have a cut.

Why is it a concern? MRSA can cause life-threatening lung and blood infections. "MRSA is a major problem, although there are pretty good drugs to treat it now," Calderwood says. Rates of life-threatening MRSA have been declining thanks to improvements in medical procedures.

Show Sources


Brian K. Coombes, PhD, Canada Research Chair in Infectious Disease Pathogenesis, McMaster University, Ontario, Canada. "Clostridium difficile Infection."

CDC: "Clostridium difficile Infection."

Stephen Calderwood, MD, president, Infectious Diseases Society of America; chief of infectious diseases, Massachusetts General Hospital, Boston.

Tripathi, P. Advanced Biomedical Research, Jan. 9, 2014.

CDC: "Acinetobacter in Healthcare Settings."

The White House: "National Action Plan For Combating Antibiotic-Resistant Bacteria."

News release, The White House.

Eric Biondi, MD, pediatric hospitalist, University of Rochester Medical Center, Rochester, NY.

CDC: "Carbapenem-resistant Enterobacteriaceae in Healthcare Settings.'

CDC: "Gonorrhea - CDC Fact Sheet."

CDC: "Facts about C. diff."

CDC: "General Information About MRSA in Healthcare Settings."

CDC: "STDs and HIV – CDC Fact Sheet."

Miller, K. American Family Physician, May 15, 2006.

CDC: "Prevention Information and Advice for Athletes."

American Society for Gastrointestinal Endoscopy: "FDA Issues Important Safety Communication: Design of Endoscopic Retrograde Cholangiopancreatography (ERCP) Duodenoscopes May Impede Effective Cleaning."

© 2015 WebMD, LLC. All rights reserved. View privacy policy and trust info