Oestrogen promotes presence of 'mucoid' form of P. aeruginosa in women with CF

Researchers from the Respiratory Research Division of the Department of Medicine, Royal College of Surgeons in Ireland (RCSI) have published a study which represents a major breakthrough in understanding why females with cystic fibrosis do worse than males. The study is the first to show that the female hormone oestrogen promotes the presence of a particular form of bacteria which results in more severe symptoms for female cystic fibrosis patients. In addition, females who were taking the oral contraceptive pill, which decreases the amount of naturally occurring oestrogen in their bodies, were found to have lower levels of the problematic bacteria.

The paper is published today in the prestigious New England Journal of Medicine.

The research found that oestrogen promoted the presence of a 'mucoid' form of the bacterium Pseudomonas aeruginosa in the lungs of women with cystic fibrosis. These mucoid type of Pseudomonas aeruginosa bacteria are coated in a slimy layer which makes them more difficult to treat with antibiotics and more difficult to clear with the body's own natural defences which leads to significant lung inflammation, explaining, at least in part,  why females with cystic fibrosis often have a worse outcome.

Professor Gerry McElvaney, Director of the Respiratory Research Laboratory RCSI/Beaumont Hospital and joint senior author on the paper commented: "This study opens the way to a new understanding and potentially new therapies in the treatment of cystic fibrosis, a condition in which Ireland has the highest incidence in the world. This research study is among the first examples which shows the effects of gender hormones on infections and therefore has major implications for conditions beyond cystic fibrosis including other respiratory diseases such as asthma."