What Is Antibiotic Resistance and How Is It Harmful to People With CF?

Antibiotics are vital medicines for many people. They are drugs that fight infections caused by bacteria, by either killing the bacteria or making it harder for the bacteria to multiply and grow in the body. People with cystic fibrosis (CF) often take antibiotics for various repeated infections. This brings up not only the question of antibiotic resistance, but also the fact that these antibiotics kill beneficial bacteria in the lungs.^1,2

What is antibiotic resistance?

Antibiotic resistance is when bacteria are able to overpower the drugs that are supposed to kill them. When drugs are not effective, the bacteria can continue to multiply and spread. This is dangerous because it can lead to:¹

• Previously controlled illnesses becoming untreatable
• Serious infections
• Dangerous illnesses becoming harder and more expensive to treat
• Significant disability or death

How does antibiotic resistance occur?

Antibiotic resistance happens when antibiotics are misused or overused. When a person takes an antibiotic, sensitive bacteria are killed by the medication. But there are some resistant bacteria that remain that the drugs were not able to kill. Repeated use of antibiotics builds up the number of resistant bacteria and changes the way the bacteria respond to the antibiotics.¹

For example, antibiotics are unable to kill viruses. If a person has a virus and is improperly prescribed antibiotics, the bacteria become used to the medication and become resistant. This is why it’s important to use antibiotics only when necessary.

Antibiotics and CF

The thick buildup of mucus in the lungs that is a hallmark of CF makes people with CF more susceptible to infections. Antibiotics can help control these infections. People with CF often take antibiotics as part of their daily medication routine. During periods of illness, people with CF sometimes get antibiotics into a vein (intravenously or IV) in addition to their regular medications. This means that for those with cystic fibrosis, the bacteria in their bodies have been exposed to a large number of antibiotics, possibly increasing the risk of antibiotic resistance.³

We all have a variety of bacteria in our lungs. Not all of them are bad. When you take antibiotics, they can also kill harmless and good bacteria in the lungs, especially if you take large amounts or many different types of antibiotics (as in CF). This decreases the diversity of the bacteria in the lungs. This decrease has been linked to CF disease progression.²

Antibiotic resistance and cystic fibrosis

A small study was done to see how antibiotic resistance affects the relationship between the diversity of lung bacteria and pulmonary function in people with CF. The researchers studied samples from 6 children with CF:²

• During well visits
• After periods of infection
• After courses of IV antibiotics
• After illness and antibiotics

Participants in the study who had the bacteria methicillin-resistant Staphylococcus aureus, which is known to be hard to treat, or other antibiotic-resistant bacteria had significantly lower bacterial diversity in their samples, as well as more aggressive CF. These participants were also more likely to have bacteria from the genus Alcaligenes, but it’s not yet known what this means for CF.²

The answer for those with cystic fibrosis isn’t to cut back on antibiotic usage, but to use medications in a more targeted, safer way to lower the risk of antibiotic resistance. This will help to ensure that the antibiotics that are given retain their effectiveness. More research needs to be conducted to see how this can be done and to develop more focused ways to treat pulmonary exacerbations and infections in people with CF.