Newly discovered mechanism in bacteria can prevent chronic infections

Wednesday 20 May 15

Pseudomonas aeruginosa

Is a widespread soil bacterium which at one point jumped to humans. It is one of the bacterial strains causing most chronic infections in humans with, for example, cystic fibrosis and chronic wounds. Over the past 40 years, Rigshospitalet has collected mucous samples from cystic fibrosis patients.

The researchers have mapped all the changes that have occurred in special variants of Pseudomonas aeruginosa in the past 40 years, but they still need to find and analyse the original strain which 'jumped' from the environment and into the lung of cystic fibrosis patients.

Antimicrobial resistance is one of the most serious health problems in the world. The World Health Organization, WHO, warns that we are heading for a post-antibiotic era where our existing antibiotics are no longer effective because the bacteria have become resistant to them. World-wide research is therefore conducted to identify new ways of fighting the bacteria.

By Mette Haagen Marcussen

One of the researchers is PhD student Juliane Charlotte Thøgersen who has spent the past three years at DTU Systems Biology and DTU Biosustain (the Novo Nordisk Center for Biosustainability) to understand how pathogenic bacteria develop during chronic infections in humans. And she has discovered something entirely new.

By using the Pseudomonas aeruginosa bacterium in cystic fibrosis patients as model system, she has discovered a mechanism which enables the bacterium to change its metabolism to be able to absorb carbon dioxide. This mechanism most likely contributes to its resistance to both antimicrobial agents and the immune system.

"When you want to find new treatment options to fight chronic infections caused by bacteria, it is essential to have an in-depth understanding of how the bacteria's metabolism changes during the infection."

Providing new knowledge about what the bacterium does to resist the immune system and antimicrobial agents, the discovery also opens up for new ways in which we can fight it. According to Juliane Charlotte Thøgersen, her discovery may also hold great potential for controlling other types of serious diseases.

"It is very likely that other bacteria use similar mechanisms to survive the immune system and antimicrobial agents, and it is possible that also cancer cells use a similar mechanism during their development. If this is the case, blocking these metabolic responses could help to prevent the cancer cells from developing further. It would be incredibly interesting to investigate this further."

On 21 May, she will defend her thesis Metabolic adaptation of a human pathogen during chronic infection—a systems biology approach. Her dream is to continue using her strong academic foundation from DTU in the biotech or pharmaceutical industry.