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Cystic Fibrosis Trust

Cystic fibrosis bugs

People with cystic fibrosis are vulnerable to lung infections, or bugs, which can be picked up from the environment or by coming into direct or indirect contact with other people with the condition (called cross-infection). While these bugs are usually harmless to people who don't have CF, they can settle in the lungs and cause permanent lung damage for those who do. Read about some of the most well-known bugs, and find out what we’re doing to combat them.

Pseudomonas aeruginosa

There are many strains of Pseudomonas, which people with CF most often acquire from the environment, and they can usually be gotten rid of or kept under control with early antibiotic treatment. However, if it takes root and starts to become resistant to antibiotics (also known as ‘antimicrobial resistant’), it can cause problems.

There is concern that people with CF are more likely to pick up particular strains of Pseudomonas from each other that are harder to treat than strains contracted from the environment. This is why CF centres should offer separate clinics for people with CF according to whether or not they have Pseudomonas.

Pseudomonas is the most common lung infection in people with CF over the age of 16. 27% of people with cystic fibrosis are living with chronic Pseudomonas infection, according to 2018 data by theUK CF Registry, 12% fewer than 10 years ago.

What are we doing about it?

Several Trust-funded Strategic Research Centres (SRCs) have been investigating Pseudomonas. An SRC run by Professor Jane Davies at Imperial College investigated better detection, understanding and treatment of Pseudomonas, and Professor Davies is now leading a new SRC, investigating ways to tailor the treatment of Pseudomonas to the individual.

A new SRC will begin in autumn 2019 at the University of Cambridge led by Dr Martin Welch looking at why Pseudomonas specifically adapts to the CF lungs, and how this knowledge might be applied to the development of new treatments. We are also co-funding a number of Venture and Innovation Awards in the area of Pseudomonas research.

Mycobacterium abscessus

Mycobacterium abscessus (M. abscessus) is the most common strain of non-tuberculous mycobacteria (NTM). M. abscessus is distantly related to tuberculosis and can cause lung infections in people with cystic fibrosis. The bug is very difficult to treat, and people with CF who develop M. abscessus can become ineligible for lung transplant until they are clear of it.

7% of people with CF are living with a strain of NTM according to 2018 data by the UK CF Registry, 5% more than 10 years ago.

Read the guidelines on NTM infection issued by Thorax, the international journal for health professionals working in respiratory medicine. These guidelines were developed as a result of Trust-funded research into NTM. Find out more here.

What are we doing about it?

A Trust-funded Strategic Research Centre, led by Professor Andres Floto, worked to discover how M. abscessus spreads and how this can be prevented, why some strains of NTM cause more lung damage than others, and how new drugs might be developed to treat M. abscessus more effectively. A second SRC is now underway that is taking the learnings from the previous research centre to help develop new treatments for people with CF who are infected with M. abscessus.

Burkholderia cepacia complex

Burkholderia cepacia complex (B. cepacia) is a rare bacteria that lives in damp or wet places like soil. It was first discovered by Walter Burkholder, a plant scientist, in 1950, who identified it on the skin of onions. It is called a ‘complex’ because there are many species of Burkholderia bacteria, some of which are more harmful than others.

B. cepacia was the first bug discovered to be passed between people with CF, leading to guidelines to minimise person-to-person infection, later becoming known as ‘cross-infection rules. In the mid to late 1990s, following research into the rise in incidences of B. cepacia it was decided that people with the bug should be kept apart from others with CF because they could be passing it between each other. Later it was found that there are several types of B. cepacia complex, some more serious than others because of the treatment-resistant nature of the bug, and so people with B. cepacia were further separated when attending outpatient clinics according to which strain they had.

4% of people with CF are living with chronic B. cepacia infection according to 2018 data from the UK CF Registry, 1% more than 10 years ago.

Other strains of B. cepacia complex include Burkholderia cenocepacia (B. cenocepacia) and Burkolderia multivorans (B. multivorans).

What are we doing about it?

Bacteria use clever defences against the body’s immune system. When they have been ‘engulfed’ by immune cells, they shoot out a defensive toxin. This kind of chemical warfare is a common defence by bacteria. As the toxin is specific to the type of bacteria, to develop effective treatments it is important to identify the nature of the toxin. The Trust funded research by Professor Miguel Valvano at Queen’s University Belfast that led to the identification of the defensive toxin that B. cepacia uses to protect itself. In follow-on funding from the Medical Research Council, Professor Valvano is exploring the damage B. cepacia causes the immune cells in more detail. It is hoped that this research will lead to treatments being developed to prevent or correct the toxin damage, in turn reducing inflammation and lung damage in people with cystic fibrosis.

Find out more about B. cepacia and what is being done to combat it here.

Aspergillus fumigatus

As well as infections from bacteria, people with CF are susceptible to developing fungal infections, including the fungus Aspergillus fumigatus. Some of these people will develop more severe conditions as a result of the infection including Aspergillus bronchitis (AB) and allergic broncho-pulmonary aspergillosis (ABPA).

Aspergillus infection can lead to accelerated lung damage in people with CF, and the current anti-fungal treatments, which the fungus is also becoming resistant to, have side effects. In addition, having Aspergillus infection will be taken into account during transplant discussions, as it may get worse post-transplant.

15% of people with CF are living with chronic Aspergillus infection according to 2018 data from the UK CF Registry, 7% more than 10 years ago.

What are we doing about it?

A new SRC investigating Aspergillus fumigatus will begin in the autumn. Dr Darius Armstrong James from Imperial College will be investigating the potential of alternative treatment approaches for Aspergillus infection. He and international colleagues working within this SRC will also be seeking to understand more about AB and ABPA, to identify those people who might be susceptible to developing these complications, and to gain clues for effective treatment strategies.

Other bugs

There are a number of other bugs that can affect people with cystic fibrosis. Some of these include:

  • Staphylococcus aureus (S. aureus)
  • Methicillin-resistant Staphylococcus aureus (MRSA)
  • Haemophilus influenzae (H. influenzae)

We are funding millions of pounds worth of research into fighting dangerous infections. Take a look at the Venture and Innovation Awards that we are co-funding to understand and treat infections and read about our Innovation Hub, which is harnessing multidisciplinary world-class research to prevent lung damage in cystic fibrosis.

Research we're funding


What is cystic fibrosis?


More information
