Anglo/Irish breakthrough in the development of fungal drug resistance

Research Lead

Biologists at Nottingham University and University College Dublin have made a breakthrough in understanding of the reproductive cycle of the fungal pathogen Aspergillus fumigatus, a major cause of death in immune deficient patients and a cause of severe asthma.

The discovery of a sexual cycle in the pathogen sheds new light on its ability to adapt to new environments and develop resistance to antifungal drugs. The scientists say the research will lead to new ways of controlling A. fumigatus, and improved treatments for patients infected with it.

Although it was first described 145 year ago, until now the fungus was thought to reproduce by the production of asexual spores only. The researchers have shown,for the first time, that A. fumigatus possesses a fully functional sexual reproductive cycle.

Dr Paul Dyer said, “This discovery is significant for providing both good and bad news. The bad news is that we now know that Aspergillus fumigatus can reproduce sexually, meaning that it is more likely to become resistant to antifungal drugs in a shorter period, and the sexual spores are better at surviving harsh environmental conditions.”

“The good news is that we can use the newly discovered sexual cycle as a tool in laboratory experiments to try to work out how the fungus causes disease and triggers asthmatic reactions.

The spores of A. fumigatus, which feeds on dead or decaying organic matter, are widespread in the atmosphere. It has been estimated that everybody inhales around 200 spores each day, but these are normally eliminated by the innate immune response.

However, the fungus has become the most prevalent airborne fungal pathogen due to its ability to cause infections in those with a weakened immune system, with at least a 50 per cent mortality rate in humans. Four per cent of patients in modern European hospitals have invasive aspergillosis; it is the leading infectious cause of death in leukaemia and bone marrow transplant patients. The fungus is also associated with severe asthma and sinusitis.