How do bacteria become resistant to antibiotics? 7 questions with infectious disease specialist Mark Dowell, M.D.

By Kristy Bleizeffer Nov 14, 2016

In America, at least 23,000 people die every year from infections caused by antibiotic-resistant bacteria, according to the Centers for Disease Control and Prevention. Another 2 million become sick from resistant bacteria.

Antibiotic use (or misuse) is the No. 1 factor leading to antibiotic resistance. That’s why the CDC designated this week Get Smart About Antibiotics Week.

“It is an effort to make people realize that everyone loses when we overuse antibiotics,” said Dr. Mark Dowell, medical director of infection control at Wyoming Medical Center. “We are trying to teach the public not to demand antibiotics, especially for their kids who have colds, and to urge physicians not to over-prescribe them.”

Below, Dr. Dowell, who is also the Natrona County health officer, answers seven questions about antibiotic resistance.

1. How do bacteria become resistant to antibiotics?

Resistance is a natural byproduct of evolution. When you prescribe an antibiotic, it may kill most of the bacteria causing the trouble. But bacteria that survive, perhaps through a genetic mutation protecting them from the antibiotic, will multiply and pass on their protective mutations. Overtime, the protected bacteria outnumber the vulnerable bacteria and it is resistant to that particular antibiotic.

So, when antibiotics are over used, or prescribed for infections that they will not be effective against in the first place, it can lead to bacteria becoming resistant. Overuse can happen in a number of ways. Sometimes physicians don’t stand their ground because they don’t want to displease their patients. Sometimes worried moms will look for doctors who will give them antibiotics for fear that their child will not get better, even when their child has a viral infection and antibiotics have zero effect on viruses.

2. On which infections do antibiotics work?

Antibiotics are used to treat infections caused by bacteria. Examples for young children include a documented case of strep throat or an ear infection, especially if the infection is on one side, the child is quite ill and you’ve tried ibuprofen but the child is getting worse. In older children, a bacterial pneumonia or a urinary tract infection could be candidates for antibiotics.

3. What kinds of infections do not respond to antibiotics?

Antibiotics do not work against any kind of virus. There are medications called antivirals that are useful for some viruses, but not many.

That means antibiotics are not effective for most cases of sinusitis, the common cold and more than 50 percent of sore throats. A lot of ear infections are viral. The classic illness most parents want an antibiotic for is bronchitis, but 95 percent of bronchitis in children is viral. Antibiotics have no effect. Bronchitis lasts up to two weeks and, frankly, parents get tired of listening to their kids cough all night long. They might demand an antibiotic and get this false idea that the antibiotic worked because their child got better. But in fact it was the natural course of the disease. The next time their child gets sick, they go in looking for the antibiotic they think cured their child’s bronchitis. 

4. How does agriculture contribute to antibiotic resistance?

The majority of antibiotic use in the United States is in agriculture. Up until lately, there has not been a lot of collaboration between use of antibiotics in humans and use of antibiotics in agriculture and how they are really related. When you start to see resistance in bacteria that live in animals, and then you’re starting to see some of those bacterial patterns show up in humans, then you have to start talking in a different way.

What they’ve found is that antibiotics were being utilized in too much of a cavalier fashion in agriculture. The goal was keeping food animals healthy, fattening them quickly and getting them to market by giving them antibiotics basically after they were born until they are slaughtered. That is really a bad idea. The bugs will develop resistance to survive. And the bugs get into the soil and they get into our food and they get into our mouths and, suddenly, some of them survive in humans, and you can hear the stories. What is encouraging is that there has been a lot more dialogue.

5. What are some of the life-threatening resistant strains?

These are seen most often in people with weak immune systems. They can be seen in very large hospitals and in large cities where antibiotic use has been high. These include some severe urinary tract infections, some meningitis and, most classically, pneumonia infections that break off into the blood stream. And we are seeing some very, very bad genetic exchanges, if you will, of bacteria coming out of countries where antibiotic use is not regulated. In many of these countries you can buy antibiotics over the counter.

There are some that I would call wicked bugs out there, but we aren’t seeing them in Wyoming yet. It doesn’t mean that they cannot be imported and pose serious health risks.

The caveat is that while there is antibiotic resistance, we still have several choices of antibiotics remaining to use on most infections. There’s antibiotic resistance which is very serious and there’s life-threatening antibiotic illness. The very concerning part is that there’s increasing high-level antibiotic resistance developing, threatening the population, yet antibiotic development has not been funded properly and has fallen way behind. So we are losing ground. And that’s a big national issue that’s really not talked about. 

6. Explain Wyoming Medical Center’s antibiotic stewardship program. 

One of the things we do with our antibiotic stewardship program is regulate what drugs we choose for certain infections. We look at the antibiotic patterns of the bugs, and we look for changes in what we are seeing in our patients, and then we apply what we’ve found within the hospital. We also talk about it in the community so physicians in their offices are choosing appropriate antibiotics. We try to really do it as collaboration.

For patients, we ask if they really need an antibiotic or if their own immune systems will be able to fight off the infection.

7. What role do vaccines play in cutting down antibiotic resistance?

If you develop vaccines against bacteria that would develop resistance over time, and your vaccine is effective in cutting down the incidence of disease in humans, then by definition you are cutting down the risk of development of resistance to antibiotics, or at least slowing it down.

That’s one of the reasons we vaccinate people. Not just to keep them from dying, but trying to cut down on antibiotic resistance. We don’t win the game, we just want to stay on the playing field.

Mark Dowell M.D.

Dr. Dowell is an infectious disease specialist with Wyoming Medical Center and Rocky Mountain Infectious Diseases (RMID), 1450 E. A St. He is the Natrona County health officer and is board certified in infectious disease and internal medicine. RMID offers a full-breadth of outpatient infectious disease care and is looking to expand its outreach clinics. For more information, appointments or referrals, call RMID at (307) 234-8700. 

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