Cystic Fibrosis: Defeating Chronic Lung Infections

Clearing the Airways

Dr. Luke Hoffman studies how different bacteria interact to improve treatment for chronic lung infections.

Brianna Oas Fall 2011 Connection

Brianna Oas is living proof of how research has improved the quality of life for patients with cystic fibrosis. The former Seattle Children's patient is now a college student (pictured with her dad and niece) who helps organize the annual CF Walk in Poulsbo, Wash.

Brianna Oas was diagnosed with cystic fibrosis when she was 3, but never felt that growing up with the disease was a liability. She appreciated how it made her life richer despite repeated lung and sinus infections that sent her to the hospital three or four times a year.

“Having cystic fibrosis taught me compassion, brought our family closer together and enabled me to meet so many wonderful doctors, nurses and patients,” Oas says.

Twenty years later, the aspiring veterinarian and current Washington State University student retains her positive outlook, but it’s tempered with a new reality. Coping with cystic fibrosis (CF) as an adult is different than dealing with it as a child. “You can’t have your mom call your boss and say you have to miss two weeks because you’re sick,” says the former Seattle Children’s patient.

Cystic fibrosis is an inherited disease that causes the body to produce unusually thick and sticky mucus. The mucus clogs the airways, creating a fertile breeding ground for bacteria that cause chronic infections and usually lead to repeated hospitalizations. There is currently no cure for CF. All doctors can do is target the bacteria with various treatments – including antibiotics – that knock them down but can’t seem to knock them out completely.

But a host of researchers are doing their best to end bacteria’s winning streak. Children’s Dr. Luke Hoffman is working to identify new and potentially better ways to treat the bacteria. The pulmonologist is researching how bacteria interact when other types of bacteria are present, which could lead to a remedy for the repeated infections that cause permanent – and eventually life-threatening – damage to the lungs of patients like Oas.

Bacteria behave differently together

Luke Hoffman Fall 2011 Connection

Dr. Luke Hoffman's decision
to study how bacteria behave
in the presence of other
bacteria may lead to more
effective treatments for lung
infections in CF patients.

Typically, several types of bacteria are present when a CF patient has a lung infection. Most research, however, has focused on one bacterium, Pseudomonas aeruginosa, because it is common in lung infections of CF patients, inflicts the most damage and is tough to eradicate.

“If Pseudomonas was on the TV show ‘Survivor’ it would win every time,” says Dr. Bonnie Ramsey, a pediatric pulmonologist who leads cystic fibrosis research at Children’s. “Once it gets established, it’s almost impossible to completely clear from a patient’s lungs.”

In the past, researchers studied Pseudomonas in isolation despite the fact that it rarely infects people with cystic fibrosis on its own. Hoffman decided to study how Pseudomonas and Staphylococcus aureus – the other bacterium commonly found in the lungs of CF patients – behave when the two are grown together.

“If Pseudomonas was on the TV show ‘Survivor’ it would win every time.”

Dr. Bonnie Ramsey

He discovered that Pseudomonas produces a compound that causes Staphylococcus (aka “staph”) to grow more slowly, making it more difficult to detect. The compound also makes staph highly resistant to the antibiotic tobramycin. This molecular interaction between Pseudomonas and staph may be just one example of how a bacterium can become more resistant to treatment as a result of adjusting to other bacteria.

That discovery is good news for Oas and others battling chronic lung infections. As researchers learn more about how bacteria interact, they can develop treatments that more effectively address how bacteria behave when they are together – as they usually are in CF lung infections – rather than as they behave alone.

“I haven’t had to go to the hospital for a while, but I still get bad infections about once a year and have to stay home for two weeks,” Oas says. “It’s exciting to hear better treatments could be on the way.”

Legacy of breakthroughs

Arnie Smith and Bonnie Ramsey Fall 2011 Connection

The breakthrough research
of Drs. Arnie Smith and
Bonnie Ramsey has made
incredible differences in
the lives of patients with CF.

Hoffman’s findings are among the latest breakthroughs made by researchers at Children’s in the fight against cystic fibrosis and chronic lung infections. Developing TOBI, an inhalable form of the antibiotic tobramycin, in the 1980s and 1990s was one of the first. Now a standard treatment for cystic fibrosis, TOBI has helped double the life expectancy of CF patients to nearly 40 years.

Ramsey, who worked with Dr. Arnie Smith and others to develop TOBI, has continued the quest to improve treatments for chronic lung infections. Now, after training under both Smith and Ramsey, Hoffman is looking for answers in the lab to questions his mentors are raising in the clinic. He’s currently leading three studies to further explore how bacteria interact in the lungs of CF patients.

“This won’t cure cystic fibrosis,” Hoffman says, “but we hope to reduce the lung damage caused by repeated infections."