Does lack of oxygen help Pseudomonas aeruginosa survive antibiotic treatment in cystic fibrosis?

Professor Iain Lamont
University of Otago, Dunedin

What is the problem and who does it affect?

Cystic fibrosis (CF) is the most common inherited disease, with around 500 New Zealanders, including many children, living with this condition. CF results in the malfunctioning of many bodily organs including the digestive tract and lungs. Characteristic of CF is the presence of excessive mucus build-up in the lungs, which creates a rich breeding ground for bacteria; in particular, the bacterium, Pseudomonas aeruginosa.

Most children are infected by P. aeruginosa by the age of ten, and it usually remains there for the rest of their lives, greatly reducing lung function, quality of life, and potentially leading to premature death. Antibiotics do the best they can to keep the nastiest elements of the infections at bay, however, increased resistance by the bacteria is rendering antibiotic treatment less effective.

Professor Iain Lamont hypothesises that Pseudomonas is more resistant to antibiotics when faced with oxygen-deprived environments; these are the very conditions that are present in the CF lung. This matters because when antibiotics are tested and refined, this is done under oxygen-rich conditions present in the lab.

 

What is this project hoping to achieve?

Prof Lamont and his team will compare the effectiveness of antibiotics on P. aeruginosa when grown in a lab in oxygen-replete conditions and oxygen-starved conditions; in addition, they will analyse sputum samples from CF patients to gain a greater understanding of the changes in gene expression when the bug experiences oxygen-starved environments such as in the CF lung.

Ultimately, it is hypothesised that bugs in the CF lung can manifest in many different ways when subjected to different oxygen levels and depending on the severity of disease state. Better knowledge around how these bugs are fostered in their growth – and the genes facilitating this – could allow for more targeted treatments, improving the quality of life for the hundreds of Kiwi children and adults living with the condition, while informing care worldwide.