Iain Lamont

Improving outcomes for cystic fibrosis sufferers with bacterial infections

What exactly happens to the bacteria in the lungs of cystic fibrosis patient when they’re treated with common antibiotics, and can antibiotic treatment be improved to better fight infection?

These questions, faced globally by researchers and clinicians treating cystic fibrosis, are being addressed right here in Dunedin by Professor Iain Lamont at the University of Otago’s Biochemistry Department in collaboration with Associate Professor Greg Walker and Dr Pummy Krittaphol Bailey at the School of Pharmacy.

Iain, who’s had a lifelong interest in understanding the interactions between bacteria and human health, has worked over many years at the University of Otago to build invaluable knowledge on the physiology of bacteria.

Using funds from the Otago Medical Research Foundation and OceanaGold, Professor Lamont has been looking at the bacteria Pseudomonas aeruginosa.

He explains infection from P. aeruginosa doesn’t affect healthy lungs, but is a common cause of chronic infections in cystic fibrosis sufferers. Unfortunately, tobramycin, an antibiotic widely used to treat the infection, is currently more effective when tested in laboratory conditions than it is in eradicating these bacteria when it reaches a patient’s lungs.

“It should work, but there is clearly barriers to its effectiveness in mucus-filled lungs and that needs to change to make a difference for the outcomes for cystic fibrosis patients; clinicians would like a better predictor of the clinical effectiveness of antibiotic treatment,” he said.

Mucus samples from the lungs of patients show low levels of oxygen, indicating that P. aeruginosa bacteria are oxygen-deprived during infection. This could explain why the antibiotic isn’t as effective as it should be.

The key to knowing what is occurring and why is understanding bacterial physiology under different growth conditions.

Professor Lamont and his team showed that P. aeruginosa contains less tobramycin when it is deprived of oxygen, explaining why the antibiotic is less effective during infection. Having more accurate information on P. aeruginosa activity will now open the doors for others to develop more targeted treatments for patients, perhaps such as using hyperbaric oxygen in conjunction with antibiotics.

A scientific paper to be published is expected to create international interest.

Further OMRF-funded research is now looking at the genetics of different strains to explain what is going on in much more detail. Understanding gene expression has the potential to provide a powerful next-generation tool for managing life-threatening bacterial infections.

Iain said Dunedin has proved a great place to build a network between the School of Pharmacy, Dunedin Hospital clinicians and an active group of Cystic Fibrosis sufferers. “We really appreciate the support from the Otago Medical Research Foundation – it simply allows us to do work we wouldn’t otherwise be able to do.”